Propylene Glycol? Low-Tox, Sierra, Amsoil

[kruL]

I learned first hand that regular green antifreeze and red Dexcool eat engine bearings upon the slightest contact.

Dexcool not only is blamed for eating away your intake gaskets and then leaking into your oil thus causing bearing failure in short order, but it is blamed for eating head gaskets to the point of leaking and blowing and it is blamed for eating holes in non-brass OEM freeze plugs. I read somewhere that there are about 4 BILLION dollars worth of pending lawsuits against GM for the Dexcool fiasco. Look it up on Google or Dogpile.com for yourself... search for "dexcool class action" or "dexcool lawsuit".

With some GM motors like the 3.1L V6 and the Vortec smallblocks, coolant leaking into the crankcase is just a matter of time. So why gamble with bearing dissolving ethylene glycol?

I have found that Propylene Glycol is the way to go. Propylene Glycol is found in Peak's Sierra brand coolant, Prestone's Low-Tox brand and is the only coolant that Amsoil sells. Propylene Glycol is also used in most deoderant sticks as a moisture binder and in Purell hand disinfectant among many other uses including use in some foods! It will not kill you if you drink it and it is bitter to the taste so your cat or dog will take no intrest in it. It does not kill fish and is not very harmful to the enviroment.

Never drink any Propylene Glycol based coolant tho, the rust inhibitors and water pump lubricant additives are what will make you so sick that you will wish you had ingested ethylene glycol instead.

Propylene Glycol is not good for your crank, rod and cam bearings but it is several hundred times less corrosive to them than ethylene glycol. You have lots more time to discover it is leaking into your crankcase BEFORE severe damage occurs. Maybe months longer?

Propylene Glycol coolants are a little more efficient than ethylene glycol because it has a little less viscosity. It robs a little less horsepower to pump it. The heat transfer is almost identical between the two.

The downside? You need about 67% Propylene Glycol and 33% water to equal a 50/50 mix of ethylene glycol in terms of freezing and maximum boil over protection.

Sierra and Low-Tox go for about $10 a gallon in Atlanta, nearly the same as most Ethylene Glycol coolants.

I use Amsoil's Propylene Glycol clear yellow that costs about $25 a gallon because it is rated for 7 years or 250,000 miles in a gas engine and 750,000 miles in a big rig.

My question is, who can test my Propylene Glycol mixture from time to time so that I will know my cooling system is in good order? I have the Sierra brand propylene glycol percentage tester that Pep Boys sells so I know my mixture is the right percentage... but I'd like to test this coolant every 3 or 4 years and maybe 100,000-150,000 miles or so to make sure it is still good.

 

[Steve S]

Which car/truck manufactures recommend propylene glycol?

 

[kruL]

Probably none. At least none that I know of...

How many recommend FP or LC?

Or how many recommend non-OEM parts? GM, Furd, Dudge, Hunda and almost all frown on Bosh plugs and wires for tune ups, they "recommend" their own brand...

Harley "recommends" Harley oil in their bikes... probably the WORST thing you can do to a Harley...

 

[nicrfe1370]

Alright, where are the forum police when you need 'em? Is there a coolant analysis in this thread?

 

[kruL]

Apparantly no one knows of any labs capable of doing a propylene glycol analysis with a meaningful interpritation. ;~(

 

[benjamming]

I had sent mine to Butler Labs. I have two results posted in the Coolant Analysis section.

 

[MN Driver]

I am also going to be switching to Propylene Glycol. Mostly because I have the GM 3.4L V6 engine, which lucky us(3.4 owners)we have to deal with it as a 'matter of time' thing too. I don't see any signs of the coolant being in the oil but the UOA shows it so I need to change it out until I have the cash to do the repair.

I think I will mix it 50/50 at least during the summer because it will protect me to 259 degrees, which I feel plenty safe with, being my temperature guage is well in the red at that point, I already know not to let it get even halfway there.

In the winter it protects to -26 degrees F which is the point where I would switch to 66% coolant to get the -76 degree F protection, which makes more sense as I don't need the worlds best heat conductivity of the fluid when it's in the frigid temps out. I plan to then swap the fluid back to 50/50 when the summer comes back if the temperature seems to creep up on me.

I don't see it at that big of a disadvatage for protection standpoint between EG and PG, because the freeze protection is -34 vs. -26 for EG and PG respectivly. The Ethylene glycol's boilover protection is only 6 degrees higher than Propylene Glycol. Either way I'm not too worried.

I personally don't trust the coolant to the extended drain intervals and I would test it or replace it once every two years at least. The stuff is cheap anyway, I just bought two gallons at $8.99 each.

 

[kruL]

Check out the Amsoil claims... it is supposed to seal many small leaks so it might help delay the inevitable.

I was running Prestone LowTox in our 95 3.1L Lumina with Amsoil 5w30 motor oil.

Wifey complained the Low Coolant light came on... no biggie, I added a quart to the radiator and filled the recovery tank to the cold line... thinking the water pump was probably going out. I figured I would change it the next week... probably the easist to change water pump ever put on a car, so I was not worried about it in the least... Maybe $30 for a brand new pump from Car Quest...

The next day, the same thing, low coolant again. Not the warning light, the radiator was full, just the recovery tank needed maybe a pint... and the day after that... for a week I added about a pint a day.

The day came to do the pump. I pulled the water pump pulley off and the inside of it was dry with no residue! The weep hole was dry...

Uhhhhhhhhtttt, Ohhhhhhhhhh!!!!

I checked the dipstic and found the oil to be 6" above the full mark and it was a whitish tan color... not foamy, but like choclate milk in color.

Crap!

Wifey had been driving it a week like this!!!

A little over 9 quarts of "oil" came out of the 5 quart capacity crankcase. That's a gallon of coolant fully mixed and blended with the oil. I drained it into a clear 5 gallon container.

I did a compression test and found the rear head had a low cylinder. So I pulled the heads and had them decked. The intake gasket blew because the Dexcool had corroded the aluminum mating surfaces around the water jackets. I cleaned the corrosion and filled the pitts with Devcon brand epoxy and painted the intake mating surfaces with Por15.

It took me two weeks to do the job in my spare time (I wasn't in a hurry) and about $400 in parts cost as the Felpro gasket set was around $200... a mistake by most accounts as the OEM replacement gaskets are supposed to be better... I did use new head bolts too. And I used a tork wrench on everything in the proper sequence by refereing to the factory Helms service manual.

Final result? The current oil analysis shows the bottom end to be looking good, no severe damage detected but there are still traces of coolant in the oil... maybe the Devcon or Por15 didn't work out?

So I'm trying some AutoRX/RXAuto (two diffrent unrelated companies that I get confused about their names) block sealer in the cooling system to see if that will stabilize it and stop the coolant smell from the heater core. If I can get it stable, I will sell the car. The Kelly Blue Book value is only $1,200 for it. If the next person gets a couple of years out of it, well what do you expect for $1200?

My point is regular antifreeze or Dexcool and regular motor oil would have likely siezed the motor or spun some bearings when the leak first got severe. After several weeks in my my garage before I hauled it off, the Amsoil/LowTox blend never fell out of full suspension. Not one drop of water ever formed in the bottom. It stayed fully emulsified. I believe that is what saved the bottom end.

Would I ever risk anything other than propylene glycol coolant and a full synthetic motor oil in any new car I cared about? No way. I'm sold for life!

 

[kruL]

Now I just need to nail down what a realistic flush and change interval should be with the Amsoil 7 year 250,000 mile rated coolant...

 

[lobo11]

PG claims to resist cavitation better than EG as well, I have it in my Dakota and have never had any issues.

 

[labman]

Compared to some of the others here, I am a little sloppy. I filled my truck with Prestone Low Tox about 5 years ago after a head gasket replacement. I don't remember adding any until I changed it this year. I didn't do an analysis, but what came out was a pretty green.

Note, PG itself has the same sweet taste as EG. I can not say what may be added to either to make it bitter. PG is inherently less toxic. It is used in RV antifreeze drinking water systems. Still, too much of anything will kill you. PG can prevent poisoning children and pets and may be safer for your bearings. Maybe I will replace the Dexcool in my 02 Cavalier with it this fall.

And sorry, I don't know where to get an analysis either.

 

[Gary Allan]

Pure PG never wears out ..but is a little viscous to pump in its pure form.

 

[Ray H]

Neither does EG. It's the corrosion inhibitors that tank over time. PG-based antifreeze-coolants are no different in that regard.

 

[Gary Allan]

Well, the Evans coolant distribution and tech support (ordering, and everything else) is just down the street. They specifically sell conversion fluid for those who use their NPG since it has virtually no tolerance for water ...since it has no corrosion inhibitors. This is right from the horse's mouth of the guy who is "d'man" (the guy who builds all the fancy ancillary stuff they sell).

Now if you're talking LowTox or the other 50/50 H20/PG mixtures ..then sure...but pure PG ..at least Evans, has no inhibitors.

 

[Matt_S]

It seems to me we're missing something important here. Ray touched upon it, but I think it deserves more attention. Comparing PG to EG is beside the point. The ONLY function that either of these perform is to raise the boiling point and lower the freeze point of the engine coolant. The chemical properties of these two are extremely similar. The only significant difference is the toxicity to living creatures, which has nothing to do with its performance as an antifreeze/coolant.

When you're comparing coolants, the corrosion inhibitors are what make all the difference. Most OE coolants these days are either pure Organic Acid Technology a hybrid of OAT and the sicilates, phosphates, borates, etc. used in the older coolants. THAT's what you need to be comparing, not PG vs. EG. Saying that AMSoil coolant is superior to Dexcool because AMSoil is PG is missing the point.

Finally, as has been discussed here before, Dexcool is not the reason for the GM intake manifold gasket failures. The gaskets are the reason for the intake manifold gasket failures. People blame Dexcool because it reacts badly when these gaskets start to fail. They don't stop to think, though, that the coolant problems are a SYMPTOM of the gasket leak, not the cause. If you change coolants because of a gasket leak, you're not going to change the fact that it was the gasket that was faulty, not the coolant.

 

[Matt_S]

As far as GM addressing their problems, I have seen them take concrete steps to correct them. They released an updated intake manifold gasket in 2003 (I believe). Also, the new 3800 Series III engines have an aluminum upper intake manifold, instead of the old plastic one that was the source of many problems. Some of the problems are due to the fact that the 60 degree V6's have an iron block and Al heads, which means the intake manifold gasket has to deal with differing amounts of expansion and contraction where it meets the block vs. where it meets the heads. Solving that would require a new engine design, which we're starting to see on the LSX V8s, 3.6L Global V6s and EcoTech I4 engines.

 

[Ray H]

quote:

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Originally posted by Gary Allan:
Well, the Evans coolant distribution...

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Point taken - I thought by "pure glycol" you were referring to the roughly 95% glycol fraction in generally available antifreeze/coolant concentrates, Gary. "Evans" is a whole 'nother horse of a different color since it is all glycol as you correctly pointed out.

quote:

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Originally posted by Matt_S:
Finally, as has been discussed here before, Dexcool is not the reason for the GM intake manifold gasket failures. The gaskets are the reason for the intake manifold gasket failures. People blame Dexcool because it reacts badly when these gaskets start to fail. They don't stop to think, though, that the coolant problems are a SYMPTOM of the gasket leak, not the cause. If you change coolants because of a gasket leak, you're not going to change the fact that it was the gasket that was faulty, not the coolant.

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That pretty much sums it up, Matt. DEX-COOL won't tolerate air in the system from bad design, mechanical failure, and/or poor previous cooling system maintenance habits. Period. The fact that GM has in the past installed chemical pellets in the coolant on the assembly line to combat coolant leakage problems in at least some engine series indicates (to me, anyway) that the company is well aware of a fundemental design or materials issue in those engine series. Whether the company has yet to properly address that issue is best left to someone smarter than me to comment on. The fact that several BITOGers have reported repeated intake mainifold and cylinder head gasket failures after replacement should be cause for concern, though. Other antifreeze/coolant chemistries do seem to be more tolerant of air; but at best, they're masking, not solving, an underlying problem - and, perhaps long enough to be the next owner's problem.