DEX-COOL

If you flush the system properly, and use a high quality traditional product, I see no problem.

DexCool was never all it was made out to be.

For starters, if you don't get ALL of the old coolant out, it'll mix with DC and gell up. Major $$$$$.

I have heard this, and accept that there is some possibility of incompatibility, but how much is "ALL". One molecule remaining? One percent remaining?

I may have to give this a try on a more or less lab basis. Will post the results if I get any.

Oh you mean DEATH-Cool? Yes, horrid stuff. My suggestion is one of those prestone flush kits you get for $4 at wal-mart, flush the living shit out of your cooling system to get it all out, then use universal coolant, no worries of incompatibility that way.

-GV

I picked up some new Prestone at WalMart an hour or so ago (which I will use in my Dodge van, re replacement of evaporator core).

All the premium antifreezes there swear they are DexCool compatible. I didnt check out the Peak claims.

Apparently there is little to worry about if those claims are true.

By "all", I mean, not just draining the radiator, but also flushing the engine block, heater core, all hoses, reservoir, anywhere antifreeze touches, until the water runs clear.

You sure it's not DC? What color is it? I don't have any personal experience with DC (I have a Ford, Isuzu, and a pre-DC Buick), but a friend gelled up her engine by topping off her reservior with non-DC AF.

I was going to do a little test to see how compatible they were, but I found no "premium" fluid on the shelf that did not have claims to be compatible. I really didnt check the Peak fluid for its claims, because I did not intend to purchase it for use in my van. I have not opened the new antifreeze, so dont know if itis green or red.

I definitely have the old green coolant in my van now, and can save it and mix it with DexCool to see what happens. After observing, I will heat the fluids to near boiling for a period to see if temperature will cause the gelling.

Does your friend know exactly what was put into her radiator? And was this the only result, or did she have a GM product that had a gasket or plenum problem? Sometimes coolant is replaced because there is another process going on which is causing the coolant system to lose fluid.

She has a 98 Regal GS, and put in Advance Auto's store brand coolant (non-DC) in her reservoir to top it off. IIRC, she said the mechanic told her she had the "orange" coolant in her car. Her reservoir and hose got gelled up. She had a flush done and everything seems OK now. Apparently she didn't put so much in as to gell up the entire engine. I guess the AA AF didn't mix much beyond the plastic tank. AFAIK, she's had no head gasket issues, or at least none she's mentioned to me.

She is in the right year range to have some gasket or plenum problems. I dont know which engine she has, but some of them are problematic.

By the way, the new Prestone I bought is fluorescent yellow...neither red nor green. So I will do this test, using the old green coolant when I drain the system.

It is a matter of curiosity more than doubting the problem may exist.

She has the 3.8L V6 MPI.

This is the one that has the plastic plenum problem. When ours failed, it did so catastrophically, with coolant entering the cylinders and a little getting into the oil. She should be aware that this could happen. Otherwise, when (or if) it happens, she could do a fair amount of damage.

Eh, her car, her issue. Her brother is a mechanic (why she didn't consult him about the AF, I don't know). Personally, I would never have purchaed the car. She said her brother mentioned something about a gasket needing to be replaced, but I'm about 99.99% sure it wasn't a gasket in contact with water.