Steel Seal: what do we know to elaborated best application approach

[Weatherb]

Decided to make an account just to share my experience with Steel seal.

2010 Toyota Corolla S 1.8L

blown head gasket, back pressure (exhaust gasses bubbling through cooling system)

Tried to isolate the cylinder that had the back pressure by removing ignition coils one at a time but was unable to isolate. When the car overheated, threw a code for cylinder 2 misfire so I figured I'd lean towards cylinder 2.

Removed Thermostat (don't know if this step was completely necessary but I saw some people saying was part of their success process, so I went along with it)

Flushed radiator with distilled water until it was clear (about 4 or 5 drains and fills)

Filled radiator with bottle of steel seal and the filled the rest of the way with distilled water. Tried running the engine with spark plug #2 completely removed and fuel injector #2 with power removed but engine would not stay running. Reinstalled spark plug #2 and ran with ignition coil off spark plug and fuel injector #2 power removed. Engine was able to maintain its rough idle this way for the 30 minutes necessary. Left Radiator cap off and heat on hottest temp lowest fan setting.

Turned Car off, reinstalled ignition coil and power to fuel injector, and let sit for about 2 hours.

Leaving radiator cap off again, ran car for another 30 minutes. All cylinders firing normally, heat on hottest temp lowest fan setting. Turned car off and let it sit overnight.

Next day late afternoon took the car out on the highway, drove for about 10 miles at highway speeds. Car driving normally, nothing out of the ordinary. Parked car and let it sit another day.

Next day, went back to the car and proceeded to bleed the air out of the cooling system topping off with more distilled water. I was pleased to notice the back pressure bubbling stopped and was able to get a nice funnel in the top of the radiator with the water level remaining full.

So, I thought I was home free happy day. Not quite yet.

Flushed the radiator a few more times and filled with Toyota pink 50/50 coolant, Bled the system again and things were looking on the up and up. Using the car on small trips (maybe 10-20 miles a day), noticed coolant starting to make its way to the overflow tank and air would collect up in the system requiring me to manually drain from overflow tank and put back into radiator. Seems I had a "partial fix".

Flushed the coolant back out of the system back to distilled water as I did the first time around, leaving the thermostat in this time around. Added a new bottle of steel seal to the radiator and since there was no more back pressure, I hit the highway for 10 miles.
Parked the car, shut it off and let it sit overnight. Next day fired it up and let it run for 30 minutes with heat on low fan radiator cap closed. Have kept the water/steel seal in the system for about a week now making small trips (fortunately is not wintertime yet and temperatures have allowed it). Nothing being pushed to overflow tank and only a little water missing out of radiator every couple days.

Took a 45-minute drive yesterday and checked the radiator after letting it cool before leaving (then 45 minutes home) and radiator was full to the brim and no extra water in overflow tank. Getting ready to flush and add the coolant back.

Just figured I'd share my experience

 

[Dmitri]

Decided to make an account just to share my experience with Steel seal.

2010 Toyota Corolla S 1.8L

blown head gasket, back pressure (exhaust gasses bubbling through cooling system)

Tried to isolate the cylinder that had the back pressure by removing ignition coils one at a time but was unable to isolate. When the car overheated, threw a code for cylinder 2 misfire so I figured I'd lean towards cylinder 2.

Removed Thermostat (don't know if this step was completely necessary but I saw some people saying was part of their success process, so I went along with it)

Flushed radiator with distilled water until it was clear (about 4 or 5 drains and fills)

Filled radiator with bottle of steel seal and the filled the rest of the way with distilled water. Tried running the engine with spark plug #2 completely removed and fuel injector #2 with power removed but engine would not stay running. Reinstalled spark plug #2 and ran with ignition coil off spark plug and fuel injector #2 power removed. Engine was able to maintain its rough idle this way for the 30 minutes necessary. Left Radiator cap off and heat on hottest temp lowest fan setting.

Turned Car off, reinstalled ignition coil and power to fuel injector, and let sit for about 2 hours.

Leaving radiator cap off again, ran car for another 30 minutes. All cylinders firing normally, heat on hottest temp lowest fan setting. Turned car off and let it sit overnight.

Next day late afternoon took the car out on the highway, drove for about 10 miles at highway speeds. Car driving normally, nothing out of the ordinary. Parked car and let it sit another day.

Next day, went back to the car and proceeded to bleed the air out of the cooling system topping off with more distilled water. I was pleased to notice the back pressure bubbling stopped and was able to get a nice funnel in the top of the radiator with the water level remaining full.

So, I thought I was home free happy day. Not quite yet.

Flushed the radiator a few more times and filled with Toyota pink 50/50 coolant, Bled the system again and things were looking on the up and up. Using the car on small trips (maybe 10-20 miles a day), noticed coolant starting to make its way to the overflow tank and air would collect up in the system requiring me to manually drain from overflow tank and put back into radiator. Seems I had a "partial fix".

Flushed the coolant back out of the system back to distilled water as I did the first time around, leaving the thermostat in this time around. Added a new bottle of steel seal to the radiator and since there was no more back pressure, I hit the highway for 10 miles.
Parked the car, shut it off and let it sit overnight. Next day fired it up and let it run for 30 minutes with heat on low fan radiator cap closed. Have kept the water/steel seal in the system for about a week now making small trips (fortunately is not wintertime yet and temperatures have allowed it). Nothing being pushed to overflow tank and only a little water missing out of radiator every couple days.

Took a 45-minute drive yesterday and checked the radiator after letting it cool before leaving (then 45 minutes home) and radiator was full to the brim and no extra water in overflow tank. Getting ready to flush and add the coolant back.

Just figured I'd share my experience

Hi Weatherb! Congratulations. Thank you for sharing this experience. It is always time consuming to apply Steel Seal. If you allow, I have a few comments:
- I am not sure about removed spark plug method: for the Steel Seal to polymerise quickly, there should be a high temperature spot at the location where it deposits (I read also about high pressure, but I cannot confirm or disproof this). Without combustion in the cylinder, there will be no such hot spot for local deposition of Steel Seal.
- I notice that you use Toyota pink SLLC. As I tried to expose above, my conclusion was that this is not the best coolant choice after Steel Seal treatment. My preference for this case is Toyota red LLC. However it requires several more engine flushes after Steel Seal (more than in case of pink SLLC) as red LLC mixing with Steel Seal has a tendency for gelling.
- Cabine heater settings during the process and while Steel Seal stays in the system: Temperature at max and fun at max to reduce temperature of heater core and hence probability to have Steel Seal in the heater core. Anyway with time, the debris of degrading Steel Seal film will be in the coolant and may clog the heater core. An air compressor flush of the heater core in reverse direction to coolant flow will be needed with time.
- Finally from now on, it is better to always drive it smoothly, without high accelerations and high rpm. Steel Seal film if very brittle. Hope it will last for long enough time. My last application made 1 year and 2.5k ago still looks good enough.

 

[Dmitri]

4. My Steel Seal application procedure on Prius gen 3 for cylinder to coolant system head gasket leak.

I assume the initial state is with Toyota coolant in the system and environmental temperature is positive .

1. Drain the coolant and flush the system with water 4-5 times. That is, each time heat the engine to thermostat opening (on idle or driving) and further until the hot coolant start to circulate through the degas (expansion) tank. That will allow to get uniform mixture of the coolant. Jack the left front wheel. Wait 10 min. Very gently open the pressure cap on the expansion tank while protecting your face (turning away) and hands (with thick gloves and rag) to release the pressure. Go in steps of 5 angular degree of rotation of the pressure cap. Drain the coolant though radiator valve on the left hand side of the care . There is no need to undo the protection. The valve knob is accessible through the opening in the bottom protection. I put a resin tube on the output nozzle through an adjacent opening. That allows to avoid splashing and safely use a receptacle for the coolant (remember it is still hot). Once it drained, close the radiator valve , un-jack the car and wait for 1.5-2 hr till the engine cools. Add water (5L) upto the Bleed mark on the degas (expansion) tank and close the pressure cap till the click.
2. After the last drain, fill the system with 2L of water , then put Steel Seal and finally top up the system with water to the Bleed mark. I use hard water as I expect it provides better result as compared to distilled water (see above). Run the engine on idle (service mode of Prius) to the temperature when coolant starts circulating via degas (expansion) tank (well after the thermostat opening) and next run it for another 15 min . In my case, the whole process is pictured in Fig. 1 and starts at the time axis label of 700 sec on the figure and at the cold engine. The onset of coolant circulating through the expansion tank can be noticed as a sudden drop in the electric water pump speed at 2000 sec axis label. It thus takes me 20 min to reach this point. After that I run it for another 15 min so as the whole 1st application process takes 35 min. Please note that if there is a strong extra pressure in the system, Steel seal manual recommends to start the process with pressure cap opened. But without pressure cap in place, it might be very long to reach the point of thermostat opening and coolant circulating through the expansion tank. Therefore it is better to close the pressure cap when the white smoke at the tile pipe starts to reduce.View attachment 262356
3. Let the layered deposition process to work through for 4-5 cycles. Each time let the engine to run till thermostat opening and coolant circulating through the expansion tank and then for another 20 min. After that stop the engine let it cooldown. I followed the approach that the whole cycle should take 1 hour. This is pictured in Fig. 2 . It shows the engine stop of the previous run (on axis label 150 sec) followed by the engine off time, when data readings were not available until till axis label 1200 sec . The straight lines connects the initial and finals state parameters. The next run process is started at 1200 sec and the coolant start to circulate through the expansion tank at about 1550 sec (just 5 min later). Since this moment I let it run for another 25 min. I repeat start/stop sequence 5 times.View attachment 262357
4. After the last run, leave the car on the same place for 24 hr to let the deposited patch to harden.
5. I followed the recommendation to make a few gentle drives with Steel Seal being in the system and drive the car for a week once per day. However it think that by this time there were no anymore sodium silicate left in the coolant (see below).
6. Flush the system with water 4-5 times (as in #1) and fill it with 50/50 red Toyota LLC /distilled water, bleed the system as per manual.

In overall the procedure is time consuming and impossible at negative environmental temperatures (or even near zero temperatures if you are well above the sea level!) because of the cooling for 24 hr without antifreeze in step #4.

In next post, as promised, I will report on the gelation of various coolants in high pH solution of Steel Seal.

5. Gelation and gel dissolving tests: how many engine coolant flushes are needed after Steel Seal

I promised to report these tests, so here they are.

5.1 Test samples
I prepared a set of different samples and conduct heated gelling and gel dissolving tests to get insight on what might go wrong in some reported cases on using Steel Seal with OAT coolants, what should be the right process to remove Steal Seal after the treatment and when to fill in the coolant, or in other words, how many engine coolant system flushes are needed. Another fundamental question was if Steel Seal application can be made at negative temperatures, with some coolant being in the system to provide antigel protection for the first 24 hours of the engine cooldown after Steel Seal application.

The sample composition (mixing ratio of coolant and high pH agent, e.g. Steel Seal) and the purpose of tests are shown in table below together with the summary of heated gelling and subsequent gel dissolving tests in water. Heating was performed in a water chamber, in the same way as discussed above.

As discussed above, my preference is given to Toyota red LLC (measured pH 8 in fresh 50/50 water solution, protection – 37°C ) as a coolant after Steal Seal treatment. Nevertheless, for completeness of this study, tests were also conducted with Toyota pink SLLC (35/65 water mixture, pH 8, protection -18°C), its mixture with concentrated red LLC as well as with the blue conventional glycol coolant officially recommended by Steel Seal for EU market. I used G11 premixed for -32°C (measured pH 8), however I never got explicit confirmation that G11 is exactly what Steel Seal quote under “blue conventional glycol coolant. ” There were no possibility to test Prestone conventional green antifreeze recommended by Steel Seal for US market (Its pH is 10 according to SDS). However you may see above a description of my experience with this coolant and spoiled Steel Seal at engine counter of 310k (metric units) .

In some cases, instead of Steel Seal (measured pH 11.2) itself, I used its solution in hard water (HW) drained after the engine treatment (measured pH 11.1). In my understanding, it is not the sodium silicate itself that may produce a coolant disaster (gelation) but the additives to Steel Seal that keep pH high. While sodium silicate has been used during the engine treatment and is gone, these additives remain in the solution after the treatment and keep the pH at values about 11.

Sample #	Composition: Coolant/high pH agent	Mixing ratio Coolant/high pH agent (protection )	Description/purpose	pH meter readings	Hardening / gelation by heat	Re-dissolving in water	Discussion section
Sample 5	Toy red LLC conc./after use HW&StSl	50/50 (-37°C)	Direct addition of Toyota red LLC to the system just after the treatment	pH 9.9	Red gel dropping	gel can be dissolved in water almost completely	5.2
Sample 6	Toy red LLC conc./ HW	50/50	Reference 1 for Samples 5&11 without Steal Seal	pH 7.8	no gel		5.2
Sample 7	After use HW&StSl	0/100	Reference 2 for Samples 5&11	pH 11.1	Thin sodium silicate film deposition indicating that almost all sodium silicate is used for engine treatment		5.2
Sample 8	Toy pink SLLC 35% /StSl	6/1 (-10 °C)	Direct application of Steal Seal in Toyota pink SLLC	pH 11.3	Lesser quantity of gel compared to #5 and #11	not dissolvable in water	5.3
Sample 9	red LLC conc & pink SLLC 35% /StSl	3+3/1 (-45°C)	Direct application of Steal Seal in a mixture of Toyota pink SLLC and red LLC	pH 11.6	Very large quantity of gel	not dissolvable in water	5.4
Sample 10	Toy pink SLLC 35% / after use HW&SS	50/50 (-8°C )	Direct addition of Toyota pink LLC to the system just after the treatment	pH 10.9	Small amount of gel	gel cannot be dissolved in water: flakes dropping out	5.3
Sample 11 (same as #5)	Toy red LLC conc./after use HW&StSl	50/50 (-37°)	To confirm results of sample 5	pH 10.7	important amount of gel	gel can be dissolved in water almost completely	5.2
Sample 12	G11 50% / after use HW&StSl	50/50 (-10°)	Direct addition of blue G11 coolant to the system just after the treatment	pH 10.7	Small amount of gel	gel cannot be dissolved ( 1 mm size clots seen)	5.5
Sample 13	Toyota red LLC conc. / used water after 4 flushes of engine	40/60 (-18°C protection)	Addition of Toyota red LLC after 4 engine flushes	pH 7.9	no gel		5.2

5.2 Toyota red LLC
Samples 5 and 11 were identical and represent addition of Toyota red LLC coolant concentrate just right after the treatment. Two samples were tested to confirm the reproducibility of results and both showed strong gelling , which however can be almost completely dissolved in water.

Sample 5 : heated gelling	Sample 11 : heated gelling
Sample 5 gel dissolving in water:	Sample 13 (after 4 flushes): heated gelling

Samples 6 and 7 were used as reference to check the effect of heating and dissolving in water of each component separately. Sample 6 contained only the red LLC coolant while Sample 7 was composed of just used Steel Seal in hard water. No gelling was observed in the two reference samples, attesting that gelling is caused by their mixture .

Sample 6: Heating of Toyta red LLC	Sample 7 Heating of used StSl

This tests clearly shows that Steal Seal engine treatment with red LLC in the system, or introduction of red LLC right after the treatment without multiple engine flushes may cause a spectacular disaster in the cooling system and engine overheating. These tests show that gel can be dissolved in water, when this experiment is conducted in an open container. By no means this may be projected on possibility of gel dissolving in water in the closed engine cooling system.

Sample 13 was used to verify that no gel may drop out of Toyota red LLC coolant after 4 engine flushes with water. Heating this sample does not resulted in gel formation.

5.3 Toyota pink SLLC
Sample 8 models the Steal Seal treatment with antigel protection by Toyota pink SLLC and Sample 11 represents introduction of this coolant right after the treatment without flushing the engine coolant system. Formation of gel was observed in lesser quantity compared with Toyota red LLC. Most importantly, in contrast to red LLC gelling, the pink SLLC gel is cannot be dissolve in water

Sample 8 heated gelling

Sample 10 heated gelling

This test shows that adding pink SLLC without engine coolant flushing or having it during the Steal Seal treatment may result in irreversible clogging of the engine coolant system.

5.4 Mixture of red LLC and pink SLLC
The red and pink coolant are compatible and can be mixed. Sample 9 mimics a situation when mixture of pink and red coolants is added to the system right after the Steal Seal treatment, or present during the treatment. Like with samples 5 and 11 utilizing red coolant, large amount of gelling was observed. However like in the tests #8, the gel cannot be fully dissolved in water. Same conclusion holds as in sec. 5.3

Sample 9 : heated gelling

5.5 Premixed G11
Sample 12 reproduces a situation of using Steel Seal with G11 coolant or adding this coolant right after the treatment. This was the case of the treatment I apply to my engine at the counter 290k discussed above. Small formation of gel was observed in the tests. The gel cannot be dissolved. In the photo, 1 mm size floating clots can be seen. This correlates well with the experience I shared above on the necessity to unclog the heater core each 2k engine counter due to solid silicates dropping caused by pH being too high.

Sample 12 dissolving in water after heated gelling

5.6 Conclusions
The summary of my findings from these tests :

• None of the tested coolants (Toyota red LLC, Toyota pink SLLC and blue G11) is compatible with Steel Seal .
• Steel Seal application should be done in water (hard water is preferred, as discussed in a post above).
• Several (at least 4 in the case of Prius 1.8L) coolant system flushes are needed to normalize pH prior to introduction of antifreeze

In case of negative temperatures, Steel Seal application can be done in G11 to allow for 24 hr cooling after the treatment (see the above post on my engine treatment at 290k), but in any case, it will require flushing the engine with water to normalize pH and switching to a more suitable coolant (my preference is given for red LLC, as I argued above). However, the coolant drain and refill can be done on a hot/warm engine, thus potentially allowing to accomplish the engine flush in cold weather. Although technically this approach is feasible, it will be extremely time consuming and expensive because G11 and Toyota red or pink coolants are not compatible and requires multiple engine flushing for coolant switch, while G11 will be needed just for treatment and will be disposed right after it.

P.S. I have some remaining data on the long-term pH measurements attempting to see the dissolving process of Steel Seal hardened films in various coolants. However, their interpretation is unclear to me. I plan to post them expecting that someone may find interpretation.

 

[Dmitri]

5. Gelation and gel dissolving tests: how many engine coolant flushes are needed after Steel Seal

I promised to report these tests, so here they are.

5.1 Test samples
I prepared a set of different samples and conduct heated gelling and gel dissolving tests to get insight on what might go wrong in some reported cases on using Steel Seal with OAT coolants, what should be the right process to remove Steal Seal after the treatment and when to fill in the coolant, or in other words, how many engine coolant system flushes are needed. Another fundamental question was if Steel Seal application can be made at negative temperatures, with some coolant being in the system to provide antigel protection for the first 24 hours of the engine cooldown after Steel Seal application.

The sample composition (mixing ratio of coolant and high pH agent, e.g. Steel Seal) and the purpose of tests are shown in table below together with the summary of heated gelling and subsequent gel dissolving tests in water. Heating was performed in a water chamber, in the same way as discussed above.

As discussed above, my preference is given to Toyota red LLC (measured pH 8 in fresh 50/50 water solution, protection – 37°C ) as a coolant after Steal Seal treatment. Nevertheless, for completeness of this study, tests were also conducted with Toyota pink SLLC (35/65 water mixture, pH 8, protection -18°C), its mixture with concentrated red LLC as well as with the blue conventional glycol coolant officially recommended by Steel Seal for EU market. I used G11 premixed for -32°C (measured pH 8), however I never got explicit confirmation that G11 is exactly what Steel Seal quote under “blue conventional glycol coolant. ” There were no possibility to test Prestone conventional green antifreeze recommended by Steel Seal for US market (Its pH is 10 according to SDS). However you may see above a description of my experience with this coolant and spoiled Steel Seal at engine counter of 310k (metric units) .

In some cases, instead of Steel Seal (measured pH 11.2) itself, I used its solution in hard water (HW) drained after the engine treatment (measured pH 11.1). In my understanding, it is not the sodium silicate itself that may produce a coolant disaster (gelation) but the additives to Steel Seal that keep pH high. While sodium silicate has been used during the engine treatment and is gone, these additives remain in the solution after the treatment and keep the pH at values about 11.

Sample #	Composition: Coolant/high pH agent	Mixing ratio Coolant/high pH agent (protection )	Description/purpose	pH meter readings	Hardening / gelation by heat	Re-dissolving in water	Discussion section
Sample 5	Toy red LLC conc./after use HW&StSl	50/50 (-37°C)	Direct addition of Toyota red LLC to the system just after the treatment	pH 9.9	Red gel dropping	gel can be dissolved in water almost completely	5.2
Sample 6	Toy red LLC conc./ HW	50/50	Reference 1 for Samples 5&11 without Steal Seal	pH 7.8	no gel		5.2
Sample 7	After use HW&StSl	0/100	Reference 2 for Samples 5&11	pH 11.1	Thin sodium silicate film deposition indicating that almost all sodium silicate is used for engine treatment		5.2
Sample 8	Toy pink SLLC 35% /StSl	6/1 (-10 °C)	Direct application of Steal Seal in Toyota pink SLLC	pH 11.3	Lesser quantity of gel compared to #5 and #11	not dissolvable in water	5.3
Sample 9	red LLC conc & pink SLLC 35% /StSl	3+3/1 (-45°C)	Direct application of Steal Seal in a mixture of Toyota pink SLLC and red LLC	pH 11.6	Very large quantity of gel	not dissolvable in water	5.4
Sample 10	Toy pink SLLC 35% / after use HW&SS	50/50 (-8°C )	Direct addition of Toyota pink LLC to the system just after the treatment	pH 10.9	Small amount of gel	gel cannot be dissolved in water: flakes dropping out	5.3
Sample 11 (same as #5)	Toy red LLC conc./after use HW&StSl	50/50 (-37°)	To confirm results of sample 5	pH 10.7	important amount of gel	gel can be dissolved in water almost completely	5.2
Sample 12	G11 50% / after use HW&StSl	50/50 (-10°)	Direct addition of blue G11 coolant to the system just after the treatment	pH 10.7	Small amount of gel	gel cannot be dissolved ( 1 mm size clots seen)	5.5
Sample 13	Toyota red LLC conc. / used water after 4 flushes of engine	40/60 (-18°C protection)	Addition of Toyota red LLC after 4 engine flushes	pH 7.9	no gel		5.2

5.2 Toyota red LLC
Samples 5 and 11 were identical and represent addition of Toyota red LLC coolant concentrate just right after the treatment. Two samples were tested to confirm the reproducibility of results and both showed strong gelling , which however can be almost completely dissolved in water.

Sample 5 : heated gelling	Sample 11 : heated gelling
View attachment 300867	View attachment 300869
Sample 5 gel dissolving in water:	Sample 13 (after 4 flushes): heated gelling
View attachment 300868	View attachment 300870

Samples 6 and 7 were used as reference to check the effect of heating and dissolving in water of each component separately. Sample 6 contained only the red LLC coolant while Sample 7 was composed of just used Steel Seal in hard water. No gelling was observed in the two reference samples, attesting that gelling is caused by their mixture .

Sample 6: Heating of Toyta red LLC	Sample 7 Heating of used StSl
View attachment 300871	View attachment 300872

This tests clearly shows that Steal Seal engine treatment with red LLC in the system, or introduction of red LLC right after the treatment without multiple engine flushes may cause a spectacular disaster in the cooling system and engine overheating. These tests show that gel can be dissolved in water, when this experiment is conducted in an open container. By no means this may be projected on possibility of gel dissolving in water in the closed engine cooling system.

Sample 13 was used to verify that no gel may drop out of Toyota red LLC coolant after 4 engine flushes with water. Heating this sample does not resulted in gel formation.

5.3 Toyota pink SLLC
Sample 8 models the Steal Seal treatment with antigel protection by Toyota pink SLLC and Sample 11 represents introduction of this coolant right after the treatment without flushing the engine coolant system. Formation of gel was observed in lesser quantity compared with Toyota red LLC. Most importantly, in contrast to red LLC gelling, the pink SLLC gel is cannot be dissolve in water

Sample 8 heated gelling View attachment 300874

Sample 10 heated gelling View attachment 300892

This test shows that adding pink SLLC without engine coolant flushing or having it during the Steal Seal treatment may result in irreversible clogging of the engine coolant system.

5.4 Mixture of red LLC and pink SLLC
The red and pink coolant are compatible and can be mixed. Sample 9 mimics a situation when mixture of pink and red coolants is added to the system right after the Steal Seal treatment, or present during the treatment. Like with samples 5 and 11 utilizing red coolant, large amount of gelling was observed. However like in the tests #8, the gel cannot be fully dissolved in water. Same conclusion holds as in sec. 5.3

Sample 9 : heated gelling View attachment 300893

5.5 Premixed G11
Sample 12 reproduces a situation of using Steel Seal with G11 coolant or adding this coolant right after the treatment. This was the case of the treatment I apply to my engine at the counter 290k discussed above. Small formation of gel was observed in the tests. The gel cannot be dissolved. In the photo, 1 mm size floating clots can be seen. This correlates well with the experience I shared above on the necessity to unclog the heater core each 2k engine counter due to solid silicates dropping caused by pH being too high.

Sample 12 dissolving in water after heated gelling View attachment 300879

5.6 Conclusions
The summary of my findings from these tests :

• None of the tested coolants (Toyota red LLC, Toyota pink SLLC and blue G11) is compatible with Steel Seal .
• Steel Seal application should be done in water (hard water is preferred, as discussed in a post above).
• Several (at least 4 in the case of Prius 1.8L) coolant system flushes are needed to normalize pH prior to introduction of antifreeze

In case of negative temperatures, Steel Seal application can be done in G11 to allow for 24 hr cooling after the treatment (see the above post on my engine treatment at 290k), but in any case, it will require flushing the engine with water to normalize pH and switching to a more suitable coolant (my preference is given for red LLC, as I argued above). However, the coolant drain and refill can be done on a hot/warm engine, thus potentially allowing to accomplish the engine flush in cold weather. Although technically this approach is feasible, it will be extremely time consuming and expensive because G11 and Toyota red or pink coolants are not compatible and requires multiple engine flushing for coolant switch, while G11 will be needed just for treatment and will be disposed right after it.

P.S. I have some remaining data on the long-term pH measurements attempting to see the dissolving process of Steel Seal hardened films in various coolants. However, their interpretation is unclear to me. I plan to post them expecting that someone may find interpretation.

6. Long-term pH measurements attempting to see the degradation process of hardened Steel Seal

6.1 Background

In difference to all previous tests, here I used fragments of Steel Seal extracted from the engine coolant system during a flush before the last application at 312k on the odometer (see above).

The samples are pictured in the figure. The typical size of fragments is around 1 mm.

Sodium silicate films produced form Steel Seal in a heated bath (see the post above Steel Seal Hardening tests: results and discussions ) and those extracted from engine looks very different. Those from engine are much thicker and are not that brittle.

From the literature, sodium silicate curing consist of two steps (see "Mechanism of Setting and Bond Formation" in https://www.specialchem.com/adhesives/guide/sodium-silicate-adhesives ). First step is exactly what was achieved with the heated bath and temperatures below 100°C.

The final curing assumes heating above 105°C (up to 200°C) and in the presence of CO2, both conditions are fulfilled at a coolant to cylinder leak. Sodium silicate reacting with carbon dioxide forms silica gel and sodium carbonate, as well as sodium bicarbonate: see Fig 13 in https://www.researchgate.net/publication/267159826 ; https://pubs.acs.org/doi/abs/10.1021/jp402850j (available at https://annas-archive.org/scidb/10.1021/jp402850j/ )). Both sodium carbonate and sodium bicarbonate, if free, would dissolve in water, rising the pH. But in hardened sodium silicate, “they are trapped inside hardened silica and/or form bounds to silica.” Although this was a quotation from Meta AI amnswer without supporting references, this statement is consistent with the observation that the extracted hardened Steel Seal fragments in the figure are not translucent as if it were a pure silica.

6.2 Motivation

Assuming that degradation of hardened Steel Seal patch is related to cracks that makes possible water to access the impurities trapped in silica, the process can be observed as an increase of pH in a coolant on a long term. If true, the rate of pH change and the final pH may be used to compare different coolants and identify the coolant which keeps the degradation slow so as the patch lasts for a longer time.

6.3 Experiment

The fragments of hardened Steel Seal from the engine were placed in an open cuvettes with Toyota red LLC (50/50 mixture), Toyota pink SLLC (35/55 mixture) and distilled water (DW). pH of the coolants was periodically measured.

First experiment was performed with Toyota red LLC , with the last point on the graph below taken directly on the car engine coolant system. At this moment I have not yet realized that a reference cuvette without test fragments of Steel Seal is needed to see a difference in pH growth due to interaction with air. The tests with Toyota pink SLLC and distilled water (DW) were conducted in parallel and were accompanied with reference cuvettes without fragments of hardened Steel Seal. Reference cuvettes were introduced once I noticed large variations in pH readings and some inconsistency in pH reading for DW. These were caused by temperature variations, and possibly some contaminations of the pH meter electrode (before each measurement it was rinsed with tap water).

In all tested samples, pH was increasing, like observed in the film dissolving tests (see above Sec 3. Steel Seal film dissolving test). However the growth rate and the final pH were much lower.

Expectation were to observe a sort of single-exponential transient process with a change for [H+] concentration in the form

[H+](time)= [H+]0- ([H+]0- [H+]f) *(1-exp(-time/T1)),

like the one shown for CO2 absorption / degassing in https://chemistry.stackexchange.com/questions/9143/approximate-time-for-pure-water-ph-to-equilibrate-in-open-air. Here the time T1 is the characteristic time of the reaction, [H+]0 and [H+]f are the initial and final concentrations of cations.

The concertation of [H+] was derived from measured pH https://en.wikipedia.org/wiki/PH . The pH meter has built-in temperature sensor and automatic temperature correction for the electrode thermal sensitivity. Additional temperature corrections was applied to measured pH to account for the water dissociation rate change with temperature using interpolation of the tabulated data from https://www.westlab.com/blog/how-does-temperature-affect-ph.

6.4 Results & discussions

The measured [H+] (data points) and numerically fitted single-exponential transient model (curves) are shown in the figure

The summary of extracted time constants, initial and final pH are shown below for red LLC, pink SLLC , reference pink SLLC (without fragments), DW and reference DW (without fragments of hardened Steel Seal)

Both from the largest reaction time constant and lowest final pH, Toyota red LLC looks to be more suitable as a coolant after Steel Seal application. However interpretation of this data is incomplete:

The time of reaction in red LLC is longest, but the difference to pink SLLC is very marginal, so these results shall be taken with caution. In addition, the assumption of single exponential process has not been validated in this study.

Surprisingly, in pink SLLC subjected only to air, pH changes much quicker compare to the case when fragments of StSl are present. Presently I have no explanations to such behavior.

Fragments of StSl has no impact on DW: nearly equal pH growth rates and final pH values are observed in DW with or without fragments of StSl. However , the origin of pH growth to the values above 8 in DW interacting with air is unclear.

6.5 Conclusions

The study is incomplete and there are many open questions and assumptions. I shared this to get the opinion of coolant chemistry experts on what was actually measured in these long-term tests.