Alright, let's get the final "definitive" answer to Dexcool...?

Question

I've been researching this whole Dexcool thing, and am beginning to see that there are several different issues (concerns) in the forefront...

First, in my reading horror stories, a majority of "plaintifs" who got wordy enough let the cat out of the bag by stating that "low coolant levels in the radiator" (aka. "gasket failures, or leaks") happened first. GM apparently has used inferior manifold gaskets for 6 to 8 years (approx. 96 thru 2003 or 4). The evidence points more to poor materials than Dexcool...

Soooooo...

1. Will "accidentally" mixing "normal" antifreeze with Dexcool automatically sludge up the system?

2. In your "professional" experience, are more failures in the cooling systems from loss of coolant first, as in gasket failures/lack of maintenance/relying on a claim of 100,000 to 150,000 miles?

I would prefer GM techs, and mechanics who are ACTIVELY working daily with this, and those who have been doing so for at least 5 years...horror writers too, but stay factual...

Answer 1

1. Mixing the coolants only adversely effects the ability of the coolant being a 'long life' coolant, it does not cause sludge.

2.Yes

The problem isn't the dexcool it's the plastic gaskets being used. Replaced a lot (And I mean a lot) of these gaskets. I use aftermarket metal gaskets and the problem does not re-occur. Usually the horror stories of blown engines are from those who do not do check fluid levels and ignore any warning signs (I.E. fluid leaking on the ground, bad smells, or fluctuations in temperature gauge readings)

Answer 2

How about some real world advice: I work in inurance claims and have to deal with engine, cooling, collision issues everyday. EVERY technician I have ever spoken with about the woes of dex-cool has stated that unless the cooling systems are constantly monitored and maintained (meaning regular cooling system fulshes and replacement of the coolant) then dex causes more problems than GM would ever believe or admit to. Dex, in theory, is a great idea. A coolant that lasts much longer than 'conventional' green coolants and are designed to protect today's high temp., aluminum engine components. The fact is when the chemicals in Dex begin to break down it turns the cooling system into sludge and goo with abandon. In the northern states this may not present a huge problem, but down here in the deep south where outside temps reach 100+ daily the wear on an engine that is only cooling to about 75% efficency is murder! I've read that GM has changed the chemical compound requirements of the Dex on their newer vehicles so the sludging issue may be solved but there are thousands and thousands of cars and trucks out there with that yellow crap in the cooling systems everywhere. I flushed the system on my personal vehicle and replaced the Dex with conventional coolant and have seen NO ill effects whatsoever.
NOTE: GM did (does) have a problem with faulty gaskets/intake manifolds on their 3.8 engines which cause coolant loss. They knew about it for years but in typical GM fashion, refused to redesign the system. There are millions of 3.8's on the road today -- all with pontential overheating problems.

Answer 3

Well, the official bulletin GM sent out says this:

Rust in Cooling System, Heater Inoperative, Blows Cold Air, Engine Overheats (Flush Cooling System) #99-06-02-012D
Rust in Cooling System, Heater Inoperative, Blows Cold Air, Engine Overheats (Flush Cooling System)
1996-2000 Chevrolet and GMC S/T Models (Blazer, Jimmy, Sonoma, S10 Pickup)

1998-2000 GMC Envoy

1996-2000 Oldsmobile Bravada

with 4.3L V6 Engine (VINs W, X -- RPOs L35, LF6)

This bulletin is being revised to include additional model years. Please discard Corporate Bulletin Number 99-06-02-012C (Section 06 -- Engine).

Condition
Some customers may comment that the heater is inoperative, blows cold air, engine may exhibit an overheat condition or the coolant reservoir has rust in it.

Cause
Vehicles equipped with DEX-COOL® coolant, which may have been operated for extended periods of time with a low coolant level, usually in excess of 32,000 km (20,000 mi), may be susceptible to the formation of a rust-like material in the cooling system.

Correction
Flush the cooling system using the repair procedures that follow.

Parts and equipment required/suggested for this correction are listed below.

1 each *Prestone® Flush and Fill Kit #AF-KITP U.S. (#00050 in Canada). This kit can be obtained from your local parts supplier and can be used on all vehicles repaired under this procedure. Save it after performing the repair, as it is reusable.
1 each *Prestone® Heavy Duty Cooling System Cleaner, GM P/N 12346500 - 1 per vehicle. This cleaner is in powder form and contains a neutralizer. Do not substitute other cleaners. The diluted cleaners that are available in liquid form are not recommended for this repair.
5.7 L (6 qt) of 100% (non-diluted) DEX-COOL® coolant (GM Spec 6277M).
1 each new thermostat, GM P/N 12563335.
2 each new radiator cap, GM P/N 15075565.
1 each *Prestone® yellow funnel. This funnel can also be obtained from your local parts supplier. It fits snugly into the radiator opening for an easy fill and is reusable.
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It goes on, but that is the part that covers this. As you see, it seems to have only happened in those vehicles where the coolant level has been allowed to drop and have over 20.000 miles. To say this is the fault of the manufacturer is like saying "I didn't check my oil, and when it was finally empty the engine blew up, so that's your fault."

Isn't that one of the fluids you check at least weekly?

Answer 4

Dexcool is fine, its the poor gaskets that GM was using. They now have updated lower intake gaskets with a metal insert to make them hold up longer. If it was a big problem, most imports would have had the 1st problems, they have used it in their cars for many years before the domestics. I agree though, its always a good idea to change it more than the 100-150k they say, but its more a problem with gasket material.

Answer 5

Dex Cool Alternative

Answer 6

Dexcool Replacement

Answer 7

all right - as in "the answers on the test were done all right" meaning every question was done correctly. alright- as in "the answers on the test were done alright" meaning the answers were OK.

Answer 8

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