CRC intake valve cleaner, safe to use?

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I'm thinking about using this product on my 2011 Malibu, 155k on her. Runs and drives great, burns no oil at 5-6k intervals.

I've been learning about how gunked up the intake valves can get with DI engines, and I suspect the intake valves on my 2.4L are pretty bad at this point. I have noticed a slight decrease in power and decrease in gas mileage. I would like to clean the intake valves and install a catch can.

I'm having some doubts though, it seem like a bad idea to dissolved the carbon, and potentially allow chunks of hardened carbon to essentially fall into the cylinder. Couldn't this cause damage?

I apologize if this topic has already been beaten to death.
 
Safe?
Sure

Effective?
I doubt it.... because you'll never get equal amounts of product to all of the valves, unless you remove the intake.

1 or 2 valves will receive most all of the product, with the others getting little to none.
 
Use it as directed. I too lost power/MPG in my 2012 Equinox. I used two cans about 500 miles apart. Wife said she could tell a difference. Will it clean the intake valves like new? I doubt it, but I would say it cleans around the valve seat pretty good.
 
Originally Posted by Backstache
, it seem like a bad idea to dissolved the carbon, and potentially allow chunks of hardened carbon to essentially fall into the cylinder. Couldn't this cause damage?


On paper, or in theory = yes.

In practice? = Nope.

Did you try the "Italian Tune-Up" on it first?
 
Originally Posted by Linctex
Originally Posted by Backstache
, it seem like a bad idea to dissolved the carbon, and potentially allow chunks of hardened carbon to essentially fall into the cylinder. Couldn't this cause damage?


On paper, or in theory = yes.

In practice? = Nope.

Did you try the "Italian Tune-Up" on it first?

Now you're talking! Plus you might want a couple cans of Seafoam, Gumout "Tune Up in a Can", STP restore and a bottle of methanol thrown in for good measure. Try to find an abandoned hiway so you can hold it down for 30 minutes minimum. I worked for me!
 
Originally Posted by Piston_slap
Originally Posted by Linctex
Originally Posted by Backstache
, it seem like a bad idea to dissolved the carbon, and potentially allow chunks of hardened carbon to essentially fall into the cylinder. Couldn't this cause damage?


On paper, or in theory = yes.

In practice? = Nope.

Did you try the "Italian Tune-Up" on it first?

Now you're talking! Plus you might want a couple cans of Seafoam, Gumout "Tune Up in a Can", STP restore and a bottle of methanol thrown in for good measure. Try to find an abandoned hiway so you can hold it down for 30 minutes minimum. I worked for me!


Or just drive it in a lower gear.
 
Originally Posted by Linctex
Originally Posted by Backstache
, it seem like a bad idea to dissolved the carbon, and potentially allow chunks of hardened carbon to essentially fall into the cylinder. Couldn't this cause damage?


On paper, or in theory = yes.

In practice? = Nope.

Did you try the "Italian Tune-Up" on it first?


Well, I just finished spraying the CRC intake valve cleaner into the intake, letting it heatsoak now. I'll give it an Italian Tune-up after it's done soaking for an hour. I've got a 30 minute highway drive to do anyways. I'll just down shift the transmission to keep the RPM's high for a bit.

Thanks for all the replies.
 
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Originally Posted by Linctex
[Did you try the "Italian Tune-Up" on it first?


That'll get the carbon off the piston heads and face of the valves but how will it remove deposits from the backs of the valves? If anything, it will bake them on even harder.
 
I might consider using this cleaner every 30K from the beginning, but now with 155K on the engine, I would say the only safe way to clean the valves is to remove in the intake manifold and manually clean the valves. If the car runs well, why mess with a good thing?
 
Originally Posted by Backstache
Originally Posted by Linctex
Originally Posted by Backstache
, it seem like a bad idea to dissolved the carbon, and potentially allow chunks of hardened carbon to essentially fall into the cylinder. Couldn't this cause damage?


On paper, or in theory = yes.

In practice? = Nope.

Did you try the "Italian Tune-Up" on it first?


Well, I just finished spraying the CRC intake valve cleaner into the intake, letting it heatsoak now. I'll give it an Italian Tune-up after it's done soaking for an hour. I've got a 30 minute highway drive to do anyways. I'll just down shift the transmission to keep the RPM's high for a bit.

Thanks for all the replies.


Higher RPM won't do anything, since the load will still be low.
 
Originally Posted by gathermewool
Originally Posted by Backstache
Originally Posted by Linctex
Originally Posted by Backstache
, it seem like a bad idea to dissolved the carbon, and potentially allow chunks of hardened carbon to essentially fall into the cylinder. Couldn't this cause damage?


On paper, or in theory = yes.

In practice? = Nope.

Did you try the "Italian Tune-Up" on it first?


Well, I just finished spraying the CRC intake valve cleaner into the intake, letting it heatsoak now. I'll give it an Italian Tune-up after it's done soaking for an hour. I've got a 30 minute highway drive to do anyways. I'll just down shift the transmission to keep the RPM's high for a bit.

Thanks for all the replies.


Higher RPM won't do anything, since the load will still be low.


I would think that higher RPM would definitely raise valve temps are there would be more fuel burnt during the time frame of higher rpms. VW even recommends 30 minutes of 3k+ RPMs to remove intake valve deposits.

https://patents.google.com/patent/US6866031


I pulled out the portion about driving over 3k rpm

An additional approach for reducing the formation of carbon deposits on the intake valves 20 is to increase the intake valve temperature, at least temporarily, since, surprisingly, it was found that any carbon deposits possibly present are removed at temperatures above 380° C. To this end, the intake valve unit, which comprises, among other components, the intake valves 20 and the valve stem guide 28, is designed with means that hinder heat dissipation in such a way that increased surface temperatures of more than 380° C. develop at least in the area of the neck 68 of the intake valves 20 in at least one predetermined region of the load characteristic diagram 74 of the internal combustion engine. This is illustrated in FIG. 4. The intake valve temperature is above 380° C. in the shaded region 112 b of the characteristic diagram. At these temperatures, carbon deposits on the intake valves 20 are removed. This region 112 b of the characteristic diagram occurs, for example, at speeds over 3,000 rpm, and in that speed range extends essentially to full load. Even if the internal combustion engine is not operated most of the time in the region 112 b during normal driving operation of a motor vehicle, nevertheless, carbon deposits that could adversely affect the operation of the internal combustion engine cannot build up, since their removal in the shaded region 112 b of the characteristic diagram occurs very quickly. For example, operation of the internal combustion engine in this region 112 b of the characteristic diagram for a period of, for example, 20 min., is sufficient to remove even a thick layer of carbon deposits. In other words, a routine expressway trip cleans the intake valves 20 sufficiently. In addition, this region of the characteristic diagram can be entered in the course of maintenance or repair work on the internal combustion engine in an automotive workshop.
 
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lucky you, girlfriends 60 thou 13 malibu 2.5L sucks a qt in 1500 with spec oil or even 10-30 syn lately, but now using 5-40 euro synthetic its better. she drives like the little old lady, not from pasadena. reading on the mazda it was noted valve temps are raised to help dissolve oil deposits + recommended some spirited driving as well. many non turbo engines seem to do well with less deposits.
 
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Originally Posted by oldhp
Use it as directed. I too lost power/MPG in my 2012 Equinox. I used two cans about 500 miles apart. Wife said she could tell a difference. Will it clean the intake valves like new? I doubt it, but I would say it cleans around the valve seat pretty good.

I hope you changed the oil 100-200 miles afterwards.
 
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Originally Posted by Triple_Se7en
Originally Posted by oldhp
Use it as directed. I too lost power/MPG in my 2012 Equinox. I used two cans about 500 miles apart. Wife said she could tell a difference. Will it clean the intake valves like new? I doubt it, but I would say it cleans around the valve seat pretty good.

I hope you changed the oil 100-200 miles afterwards.

You are correct in suggesting that . I had a large amount of junk in my oil after using the CRC cleaner
 
Originally Posted by dbias


I would think that higher RPM would definitely raise valve temps are there would be more fuel burnt during the time frame of higher rpms. VW even recommends 30 minutes of 3k+ RPMs to remove intake valve deposits.

https://patents.google.com/patent/US6866031


I pulled out the portion about driving over 3k rpm

An additional approach for reducing the formation of carbon deposits on the intake valves 20 is to increase the intake valve temperature, at least temporarily, since, surprisingly, it was found that any carbon deposits possibly present are removed at temperatures above 380° C. To this end, the intake valve unit, which comprises, among other components, the intake valves 20 and the valve stem guide 28, is designed with means that hinder heat dissipation in such a way that increased surface temperatures of more than 380° C. develop at least in the area of the neck 68 of the intake valves 20 in at least one predetermined region of the load characteristic diagram 74 of the internal combustion engine. This is illustrated in FIG. 4. The intake valve temperature is above 380° C. in the shaded region 112 b of the characteristic diagram. At these temperatures, carbon deposits on the intake valves 20 are removed. This region 112 b of the characteristic diagram occurs, for example, at speeds over 3,000 rpm, and in that speed range extends essentially to full load. Even if the internal combustion engine is not operated most of the time in the region 112 b during normal driving operation of a motor vehicle, nevertheless, carbon deposits that could adversely affect the operation of the internal combustion engine cannot build up, since their removal in the shaded region 112 b of the characteristic diagram occurs very quickly. For example, operation of the internal combustion engine in this region 112 b of the characteristic diagram for a period of, for example, 20 min., is sufficient to remove even a thick layer of carbon deposits. In other words, a routine expressway trip cleans the intake valves 20 sufficiently. In addition, this region of the characteristic diagram can be entered in the course of maintenance or repair work on the internal combustion engine in an automotive workshop.


Figure 4 seems to show a shaded region consisting of high pressure and RPM, not just RPM. The body of the patent doesn't specifically call out load in relation to RPM.

I don't fully understand how manually down-shifting the transmission to achieve >3k RPM will sufficiently raise valve temperatures by that much. More fuel is obviously needed, to account for the increased losses at higher RPM; however, the actual load is still the same (again, with the added load due to frictional and pumping losses).
 
On a high mileage gasser engine I would think that you run the risk of plugging the cat with all that carbon heading down stream.

Btw..."Italian Tuneups" don't work on valves because the they never get hot enough to bake off the carbon. Remember that you always have "cool" intake air hitting the valves. IIRC Engineering Explained (UTube) has a video on this very thing.

"Italian tuneups" would free stuck piston rings back in the day.


Possible Solution: Pull the intake to see if they need cleaning, then rent a walnut shell blaster to clean each valve individually. You'll have to rotate the crank so that the intake valve is in the closed position (don't want crushed shell material to get into the combustion chamber), and you'll need a shop vac so you can spray and suck w/out getting the media all over the place.
 
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I'm not sure if I'll be using this again. I sprayed this stuff right after the MAF sensor, and even a couple of hundred miles later the air intake and throttle body was covered in this cleaner which left a heavy oil residue. No difference in performance that I can tell. Gas mileage not checked yet.
 
Originally Posted by ofelas
I'm partial to the Mopar Combustion Chamber cleaner if needed, right before an oil change.


Agreed - that stuff definitely works!
 
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