Coolant Types and GM Stop Leak pellets?

[M U Tiger]

I've heard all sorts of things about which coolant (antifreeze) to use and which not to use in my son's 1994 Cutlass Supreme convertible with the 3.4L DOHC engine: Dexcool only; don't use Dexcool; use green antifreeze, etc.

I want to flush the dirty coolant over Christmas break and would like some recommendations on which brand/type to use.

Also, does GM recommend using coolant pellets (StopLeak) in the newly flushed colling system? My Allante Forum friends say it's very important to put the pellets in the Allante coooling system.

Jim

Webster Groves, MO

[94 olds vert]

When I replaced my radiator. I used green antifreeze and filled it up and bled the air out. You don't need deathcool.

 

I wouldn't put in any stop leak pellets. As for the bleeding of the cooling system there are instructions in the manual.

[Dark Ride]

X2, Green all the way.

[White93z34]

I always run what the manufacturer states, so in your case green coolant and no stop leak pellets.

[Schurkey]

There's several kinds of coolant; and fifty different brand names.

 

NONE of them are especially "bad" for your engine. Some have special advantages that you may or may not find appealing.

 

Propylene glycol is considerably less poisonous than ethelyne glycol. A little more viscous than ethelyne; and with slightly lower freeze protection (but still plenty effective.) It's the "animal lover's" coolant. If you dispose of ethelyne glycol properly, and you maintain your vehicle...animals will never get near your coolant to begin with.

 

"Ordinary" green ethelyne glycol is as inexpensive as it gets.

 

"Extended life" ethelyne glycol is what I've moved to for most of my vehicles. I don't use "Dexcool" by brand name; but I've had Dexcool in my pickup when I bought it, and there were no problems whatsoever. When Dexcool was a new product, there were some issues. I think it got blamed on "air in the system", but that makes no sense at all since the overflow tank (which always has air in it) was usually not affected when the coolant deteriorated. My suspicion is that the early Dexcool had compatibility problems with oil or exhaust gas; when shitty castings allowed crappy gaskets to blow out, the coolant got contaminated with oil leakage and blow-by.

 

Don't be an idiot and buy "pre-mixed" coolant. You're paying almost "pure" prices for diluted coolant. I do recommend that you buy DISTILLED water to add to the "pure" antifreeze to achieve your preferred amount of freeze/boilover protection. When you finish flushing the coolant, remember that the block is still holding PLENTY of flush water; unless you can remove the block drain plugs (I replace them with brass draincocks) so that all the flushwater drains from BOTH SIDES of the block. Not all engines HAVE drain plugs; but most do. If you don't drain the block, be sure you pour in the appropriate amount of anti-freeze FIRST. Get the anti-freeze in BEFORE adding water to top-off the system.

 

If you don't have a coolant leak, you don't need stop-leak pills.

 

If you DO have a coolant leak, 99% of the time you should be FIXING THE LEAK, not plugging it with cellulose and silicates.

Edited November 29, 2010 by Schurkey

[Night Fury]

1) dex-cool IS NOT the devil

 

2) Your car came with green from the factory, so use that.

 

3) Never put ANYTHING in your cooling other than coolant/water...... Unless your overheating in the Sahara and you could use a restroom break....