Coolant in engine oil, Is PG coolant less destructive?

[JOAT]

Recent oil analysis (22ppm potassium at 46k on oil) indicates a possible small intrusion of coolant into my engine oil. From a few posts here and elsewhere, it was suggested that EG damaged bearings at less than .5% by volume, but PG did not at up to 8%. I can find no substantiated proof of this. Besides searching, I have talked with Blackstone, Fleetguard, and Fleetguards oil analysis tech. None of them had any info that one was less damaging than the other.

If I were sure, then I would switch to PG as a precaution, but hate to waste good coolant if no advantage. Anyone have any input on this? Preferably with some studies or sources I could refer to.

Thanks
Don

 

[JohnnyG]

I SERIOUSY doubt that there are any PG's out there with the required corrosion inhibitors that would make them acceptable for use in an automotive application. You risk major engine damage without those inhibitors on a totally cast iron engine. Throw in some aluminum (like a rad) and everything is out the window.

Last expieriment I did with PG had it freeze solid at -18°F, no dilution.

 

[bulwnkl]

quote:

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Originally posted by JohnnyG:
I SERIOUSY doubt that there are any PG's out there with the required corrosion inhibitors that would make them acceptable for use in an automotive application. You risk major engine damage without those inhibitors on a totally cast iron engine. Throw in some aluminum (like a rad) and everything is out the window.

Last expieriment I did with PG had it freeze solid at -18°F, no dilution.

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What in the world are you talking about???

All the low-toxicity antifreezes on the market in the USA are propylene glycol. They work extremely well and have very, VERY similar freeze-protection to standard ethylene glycol.

Please... look at a bottle or two.

 

[Jay]

Talk to some of the propylene glycol manufacturers and find out what their take is. I know that Neo makes PG coolant, and they also claim that it does far less damage than EG if it gets in the crankcase.

 

[JohnnyG]

Obviously I don't know what I'm talking about! I just did a little research and came up with this:

Lasts Longer
AMSOIL Antifreeze & Coolant contains a proprietary poly organic acid technology. It eliminates the need for periodic changing or recharging of cooling systems. There is no need for supplemental coolant additives. AMSOIL Antifreeze & Coolant provides extended service life in all gasoline and diesel vehicles. It can be used for seven years or 250,000 miles in passenger cars, light-duty trucks, vans and recreational vehicles. It lasts seven years or 750,000 miles in over-the-road diesel trucks.


The OAT corrosion inhibitor adds. are the same as is used in DEXCOOL, which is only certified to 5 years 150,000 miles by GM. I was using the stuff used for RV's and such in my expieriment.

My bad.

 

[JohnnyG]

BTW the Amsoil stuff is a PG.

 

[JOAT]

I guess I should have restated the post title. I am asking about coolant that has contaminated engine oil, not coolant being used as coolant...

Is one less damaging to engine bearings when it is in the lubricating oil?

 

[JOAT]

quote:

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Originally posted by Jay:
Talk to some of the propylene glycol manufacturers and find out what their take is. I know that Neo makes PG coolant, and they also claim that it does far less damage than EG if it gets in the crankcase.

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Thanks Jay, I'll check that out. I talked to Fleetguard support and they couldn't say if one was any worse.

 

[labman]

If you are getting glycol in the oil, you are getting water. PG is slightly higher boiling than EG and more oil soluble. That should make it slower to vaporize out of the oil. These problems only tend to get worse. I doubt PG would protect your bearing much, but might be better for children and pets when the head gasket eventually blows.

Will yield to an authoritative source.

 

[JOAT]

Found this on an Ams dealers page "Dow Chemical reports that bearings exposed to oil with 8 percent propylene glycol show no excessive wear while those exposed to oil with 1 percent ethylene glycol fail rapidly."

I fired off an e-mail to Dow PG division asking for related info.

Also did an experiment the other day with EG & PG each mixed 5% with oil, heated, then mixed, then blended. PG mixes very easily, where EG seems to stay in droplets. After separating PG is clean, EG is partly an emulsified, sticky mess.
HERE is the Webshots page with PICS and descriptions *11 pics total, is still uploading as I post this.

 

[TooSlick]

JOAT,

The testing you are referring to was done by Detroit Diesel - in one of their "Series 60" four stroke engines as I recall. They added 8% PG coolant directly to the crankcase of an engine on a dyno, then ran it @ rated load for 1 hour. Upon inspection, there was no damage to the motor....

I've been running the original Amsoil PG based coolant in my 1995 Toyota pickup for the past four years and it seems to work very well. I drained/refilled with the second batch about a year ago ....

I have not tried the new, extended life, "POAT" formulation,which has only been on the market several months.

Tooslick

 

[JOAT]

Just an update. Dow customer service replied they had no info on PG vs EG. Will try finding info from Detroit Diesel.

 

[Hirev]

Did you cut open and check the oil filter? Coolant with water has a way of collecting in the oil filter plugging it up and sometimes destroying it? Much the same way not much water will pass through a good fuel filter.

 

[Gary Allan]

quote:

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PG is slightly higher boiling than EG and more oil soluble. That should make it slower to vaporize out of the oil.

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PG has a boiling point of 375°F, IIRC. There is NO WATER IN PG coolant ..or if it is ..it's not being used as it can be.
EVANS COOLANT

You can use a very LOW system pressure with straight PG. This could prevent any head gasket leakage.

 

[Gary Allan]

I just got back from Evans Coolant's distribution center ..which is here in Pottstown (the have offices elsewhere ..but all shippments come from Pottstown) and I learned a few things.


You can use a zero pressure cap ..but only if your rad cap is attached to the suction side of your water pump. Otherwise the resistance of your rad will cause you to pump your coolant out the cap (DUH!

) ..the lady just didn't say the right words for it to click in my head at first. They offer 7 lb caps for daily drivers that don't have specifically configured systems for using their NPG or NPG+ coolant. They also have just about every trick adapter that I've ever seen as far as thermostat housings and hose adapters. There are no corrosion inhibitors in Evans PG products ..hence the need to fully purge the H2O from the system. It has no tolerance of more than 5% water content before your run into corrosion problems. Pure PG gets viscous when cold ..so initially ..it's harder to push than EG/H2O mix.

If I had a head gasket leak ..I might be tempted to try Evans and the low pressure alternative to see if it eliminated the situation ..especially if the car was a beater/older. The only thing is that Evans is about $27/gallon ..but if it works ..it's better than a mulit $100 head gasket change if you're not equipped to do the work.

The guy, Dave (their tech support guy), let me have a 7lb cap for $5. The coolant is going to cost me about $75.

btw-Evans never wears out ..it's a true lifetime coolant.

 

[JOAT]

quote:

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Originally posted by Hirev:
Did you cut open and check the oil filter? Coolant with water has a way of collecting in the oil filter plugging it up and sometimes destroying it? Much the same way not much water will pass through a good fuel filter.

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Both filters no water, coolant or sludge. Actually surprisingly clean considering they'd been running about 46,000 miles.

 

[JOAT]

quote:

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PG has a boiling point of 375°F, IIRC. There is NO WATER IN PG coolant ..or if it is ..it's not being used as it can be.
EVANS COOLANT

You can use a very LOW system pressure with straight PG. This could prevent any head gasket leakage.

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I've considered EVANS, my main concern is limited availabilty, and the fact that I've ruined it if I ever was in a bind and had to add water.

I was also looking at AMSOIL's new yellow stuff. It's PG, can be ran undiluted if desired tho it's recommended at a 70/30 ratio for max cooling.

So far as to responses to my original question whether PG is less damaging than EG;
-Prestone, no knowledge of tests showing less bearing damage
-Fleetguard, no knowledge of tests showing less bearing damage
-Dow Chemical, no knowledge of tests showing less bearing damage
-Fleetguard UOA- no knowledge of tests showing less bearing damage
-Blackstone, no knowledge of tests showing less bearing damage
-AMSOIL, believes information is correct, but only provided corporate literature, not actual source of test info
-Several websites and posts attributing this info to Detroit Diesel, Dow Chemical or Arco Chemical
-old posts from 2001 & 2002 here and at Noria where people stated it as fact and no-one contested that...

Based on my own experience with EG, I know that it emulsifies and clogs filters and passages. My tests with 50/50 PG/Water shows it mixes cleanly with oil. Thus I will go to PG, as it certainly seems it would be less of a problem with clogging and displacing oil. Whether it breaks down into corrosives like EG does or not, I still don't know.

 

[MolaKule]

quote:

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Recent oil analysis (22ppm potassium at 46k on oil) indicates a possible small intrusion of coolant into my engine oil.

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Some potassiums emantes from potassium triborates, in which the source may come from either the dispersant, or the anti-wear additive, or the coolant.

If the analysis showed glycol and/or water, then you have coolant intrusion. Send the next batch of oil to Terry and find out for sure.

Any coolant in the oil is going to degrade the oil and ruin bearings in the long term.

 

[Stinky Peterson]

Don, what coolant are you using now and does it contain potassium?

 

[JOAT]

Fleetguard Compleat ES (EG), my understanding is it has potasium. At this point, I'm waiting to see what the next analysis shows, as at that low level, it could even have been prior contamination that just got missed on earlier UOA's (changed oil cooler o-rings just prior to that oil fill).

I was mostly intrigued by the possibility that PG might be less prone to breaking down into clogging and corrosive substances than EG. Not that I want it in the oil, but if it buys more time in the case of a small leak, it certainly is worth considering when deciding which coolant to use.