Hmmmm... scratching his chin. I switched to aluminum gaskets and still run Dex-cool. I had planned on swithing coolant this spring, I may keep running the D-Cool and watch the coolant levels.

That'* definitley interesting to see the same problem with another coolant.

Thanks for sharing that Dan

Hi

Peak LL has been said to also be a OAT coolant as dex and other "universal or safe for all models..all makes.."

The reason is that all these OAT coolants contain 2-eha which is a known plasticizer. The aluminum GM gaskets were designed with this in mind..hence the aluminum.

I have plastic Fel Pro LIM gaskets I installed in a Olds LSS about 6 yrs ago before the Alu GM ones came out. We did a UOA last August and virtually no traces of sodium or potassium so the plastic gaskets are still holding.

The secret..? We used Zerex G-05 which is a HOAT with small amounts of silicates.

The Zerex doesn't necessarily stop the plastic gasket from deforming though. Many of the Regal guys swear by the G05 coolant and still have the gasket issue.

I do hear Fel Pro may have started manufacturing and packaging an aluminum gasket set.

Interesting information, sure does debunk a lot of commonly held perceptions of Dex-Cool.

One thing Dex Cool sure does do though, and why I'll never run it in my cars, is it sludges up like crazy, and this is notorious for killing water pumps and blocking heater cores in 4.3'* like mine. I couldn't believe the orange gunk I found in my truck and it'* very well maintained! All fixed now though.

Thankfully both of my cars have aluminum frame gaskets now, no coolant leaks for me. The truck is all green, the Buick is a mix of green and orange. But with this new knowledge I won't worry about it so much.

Oh, and if you want it I have a pic somewhere on the home computer of aluminum gaskets that have been run about a year with Dex Cool and maybe a small amount of green. I'll see if I can dig it up.
.
.
.

Add them to the thread. The reason for sludge build up is because air gets into the cooling system.

Hmm, I thought I had a more gasket specific photo than this, nevertheless here is a photo of my aluminum gaskets after about a year and 10-15,000 miles.



A little bit more digging...

Here'* my truck after 63,000 miles and almost 14 years of Dex Cool:



Seeing that clean lifter valley always makes me smile. My Buick is getting cleaner and cleaner too, for 128,000 miles it had regular dino oil changes, but I've noticed in each of the three times I've pulled the LIM it has gotten successfully cleaner.

Also from my truck, sludge!



4.3'* seem to have a worse problem with sludge than most other engines. Dunno why. The Buick didn't have hardly any at all.

I have pics of my Buick with the original LIM gaskets and Dex Cool at 137,000 miles but it doesn't look much different than those already posted here, plus I don't know where it is lol.
.
.
.

Wow Nicely done! It doesnt help that GM has redesigned the gaskets 3 or 4 times.

That last one looks like you got a lot of air in the cooling system.

Hi

Many likely don't know for sure what they are using for coolant. "If its green..it ain't dex" seems to be the basic idea of coolant for many people.

Color means very little these days. Because G-05 is clear and hard to see, I put red food dye in it for that reason but this doesn't make it a Toyota coolant because its the same color.

If the coolant is silicated, it is most definitely not a OAT coolant.

The 4.3, used in many S10/Blazer trucks had a radiator with a off set cap. This cap, like all "weighted" caps, is known to lose sealing integrity and allow air in. The mud/sludge is likely a combination of sealing tabs and iron oxide.

The cure? R&R the radiator, replace the cap with a stant and use a silicated coolant.

Very true. My coolant is orange and came in jugs that had a huge GM logo on them and said Dex-Cool.