Prestone Rather Than DesCool ?

Bob wrote in news:ls0irf$fuc$ snipped-for-privacy@dont-email.me:

I wouldn`t, have not heard good things about the combo antifreezes. KB

If you can save a few bucks, I'd go for it. What's the worst that could happen?

From what I've read, yes, it's fine to use the Prestone. The only difference is it won't last 100K miles like the dexcool supposedly does. Of course, you could use Dexcool and not worry. The price can't be much different. The big issue about dexcool, again, this is from what I read, was that people who are always opening their radiator cap to 'check the antifreeze' are letting air into the system and the air reacts with the dexcool and if enough air gets in it can cause problems. If the system is just left alone and the level checked by simply looking at the level in the overflow bottle there should not be a problem. I would NOT use Dexcool in any car that did not use it from the factory. And if you mix other non-dexcool stuff with it you lose the long life benefit.

Prestone says it meets GM 6277M, the specification for DexCool:

OTOH why bother switching when Prestone makes its own version of DexCool, and at most you'll save just $15 every 5 years or 150,000 miles?

Sometimes when you switch from one type of antifreeze to another, the new stuff dissolves deposits left by the old coolant, and in my case the changeover turned the coolant a murky brown-green in a month, despite the system having been flushed with a strong chemical, just before refilling. This was with a 1993 Ford, over

15 years ago. It had conventional green coolant, and I decided to try DexCool. I still have the car and still run DexCool, and it's never needed new cooling system parts, except a radiator cap and hoses. I also run DexCool in a 1986 Toyota that was given to me, about 5 years ago, because its original owner had long used it (he did not assume it was like Toyota antifreeze just because both were red).

Long-term, using DexCool is supposed to save you money due to the extended change interval, and the Prestone equivalent is just fine.

However, I know several people who have changed from DexCool to conventional antifreeze because they were getting black gooey material in their cooling system, the source of which was never properly tracked down but which went away when they moved to Prestone.

--scott

tection is active.

I had that problem with my Chevy Lumina or rather many people had that prob lem with their coolant on that car. The problem was supposed to be solved b y slightly changing the design of the cap by adding a little spring to the vent the equalized the pressure with the atmosphere. I never could figure o ut how that was supposed to work.

I'm up in the air about Dexcool. Haven't read much on it lately. Early on it screwed up a lot of cooling systems, for whatever reasons. My sister had an expensive problem with a Buick because of Dexcool. Might be better now, but I flushed if from my Lumina and went with green Prestone for the life of that car. Dexcool is in the 2003 Impala I bought last year and looks clean. And if it all looks good when I get around to changing it I might use it in there again. Any sludging and I'll go to green Prestone. No big deal. One thing I wouldn't do is mix Dexcool with other anti-freeze.

roblem with their coolant on that car. The problem was supposed to be solve d by slightly changing the design of the cap by adding a little spring to t he vent the equalized the pressure with the atmosphere. I never could figur e out how that was supposed to work.

GM wanted to have a coolant that would last and last but maybe that's like trying live to be 150 years old - it just ain't natural! As it goes, I don' t keep my cars longer than 3 or 4 years nor do I drive much in a year so de tails like that are not too important to me. It might be important for thos e guys that vow never to buy another car again.

Prestone sells DexCool spec fluid.

If you are really wondering about mixing two-year coolant with five-year...it just turns it all into two-year. It says that on the bottle and in the fffing manual.

Don't forget the true weak link is that the pressurized cap has a one-year expected life span!

GW

You may have gotten lucky with using it in the Ford. There are some Fords that had gaskets that were not compatible with Dexcool. I read a long article on it about 5 years ago where they talked to a ford engineer about the whole question of what coolant to use.

I tried some Orange stuff, not sure if it was literally dexcool or some other name, in my 92 explorer and as soon as I started using it little orange foamy "leakage" bubbles started forming around the edges of all the hoses where they were clamped down. None of those places had ever leaked any of the green stuff but somehow that orange stuff managed to ooze it's way out. I drained it back out within a few months and went back to the green stuff and no more of that problem.

Where did you get the idea that caps have a one year life span. Most of mine came with the car and are still working just fine, some for over 20 years.

I would guess the change in cap design allowed the system to form a vacuum of a few psi instead of letting the reservoir suck in air as it cooled. The vacuum would have caused the hoses to slightly collapse when cool. That would prevent a lot of "fresh air" full of oxygen from getting in and reacting with the dexcool and degrading it.

The old Lumina cap had a design that prevented a vacuum from forming in the radiator. If there's no vacuum present, water won't be sucked back into the radiator from the coolant reservoir on cool-down. What gives? OTOH, I suppose that all that doesn't matter much these days.

With the coolant recovery system there is not supposed to be any air IN the engine side of the cooling system. There will be air inside the coolant recovery bottle (on top of the coolant that's in it) but that air is OUTside the actual cooling system. So when the engine cools down the coolant will either flow back into the engine side and form a vacuum in the space above the coolant in the recovery bottle. I doubt it's much of a vacuum, you wouldn't want to collapse the bottle but a few PSI isn't going to hurt it. I'm just theorizing as to what the change might have been in the cap and why. The issue was the need to keep fresh air from being able to mix with the dexcool and the only way to prevent it is to do what you can to stop air from getting into the bottle. Not opening it keeps giant amounts from getting in when you take the cap off, forcing it to form a slight vacuum (by having a spring loaded valve in the cap) would be a way to stop air from "breathing" in and out as the engine heats and cools.

I always use Prestone, no problems yet. I change it at least once a year.

I thought Prestone specifically had a Dexcool product. Bought some back in February. Did they stop already? I could swear that's what the bottle said, as I wouldn't have put anything else, being that's what the manual calls for.