PeachParts Mercedes-Benz Forum - NEVER use DEX-Cool in your MB engine

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NEVER use DEX-Cool in your MB engine

Oh my! I knew that was bad stuff but I had no idea it did that.

Quote:

Originally Posted by gatorblue92 (Post 3273950)

Oh my! I knew that was bad stuff but I had no idea it did that.

The interesting thing is that, sometimes, Dex Cool turns to mud. And sometimes it doesn't. Lot's of theories as to why; none seem to be overwhelmingly convincing.

In any case, I would not put it to the test, especially in an application that did not call for it in the first place.

Never use ( insert brand of motor oil ) , it will wreck your engine ( if your oil change interval is 20,000 miles )

Dex Cool is just fine. Lack of maintenance isn't, and that is what is causing the sludge. Dex Cool does not like air at elevated temperatures ( low coolant levels ) caused by lack of regular fluid level checks.

Look at picture 2, the sludge is forming from the _TOP _ down not bottom up as is typical with regular antifreeze. A car with poorly maintained regular antifreeze can have sludge this bad, it lies unseen at the bottom of the rad and block. Few people see the inside of an engine so it gets minimal air play.

The side tank in pic 2 has the rad cap on the left, outlet to water pump on right. The oil cooler shows sludge on the rad cap side ( top ) .

Pic 3 shows sludge and, _no liquid_. If this had been a properly maintained system, you would see liquid. ( This system will have an overflow bottle so regardless of sludge we should be able to see liquid. ) If you look at an angle towards the rad you can see the rad header, this is normally covered with liquid.

A few years ago I put a 99 Blazer together for Mom and Dad, it had a bad transmission and a intake manifold coolant leak. Intake leaks are common on these engines due to oh too thin preformed silicone gaskets in a plastic carrier.

When building a car, I do a major overhaul of the entire vehicle, engine, trans, suspension and such to prevent future breakdowns. The motor had reasonable oil changes but the coolant leak wasn't tended to.

Yes, there was sludge at the top of the rad but, there was _ZERO_ sludge in the bottom of the block. In fact, the block coolant passages looked like brand new clean cast iron as did the freeze plugs.

Fresh Dex Cool went into this engine post rebuild without a second thought.

My uncle had a '96 cavalier that he bought new, drove it to 138k before the brake lines rusted out and he trashed it. Never touched the DexCool coolant, and it was still "ok" looking and it never overheated....he drove the car for 14 years.....only did oil changes and 1 transmission fluid change, other than the brakes rusting it never broke down. Very odd indeed.

Read the Organic acid technology of DEX-COOL
Antifreeze - Wikipedia, the free encyclopedia

GM Owners Still Steaming Over Dex-Cool
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Top 746 Complaints and Reviews about DexCool in GM Engines
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http://www.stevesnovasite.com/forums/archive/index.php/t-128547.html
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General Motors Class Action Lawsuit | GM Lawsuit | Girard Gibbs LLP
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Old GM Settles Lawsuit With “Dex-Cool” Owners

There is sufficient LEGAL proof that GM dragged the lawsuits out until after the bankruptcy, finally settled them for a tiny fraction of what it should have been.

In My Opinion:
Using this product in any MB is BEGGING for catastrophic engine failure.
The MB engine / cooling system is NOT DESIGNED FOR IT.
The simple fact that Dex Cool reacts badly with air at elevated temperatures = using it in the majority of older vehicles is a recipe for disaster.

Legal fact = nobody has a right to prevent a vehicle owner from filling the cooling system with anything they desire = Elmer's Glue, salt brine, muriatic acid, geotechnical engineering drilling fluid.

The car is yours = the repair bill is yours.

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Dexcool is not suitable for systems that have an "air pocket" expansion tank like our cars - it will cause some trouble (very little because the tank is plastic)

On other cars with radiator caps on radiators and separate expansion tank (system chock full of coolant) this works perfect. This failure usually shows up with low coolant level in the radiator and also due to the "loose valve" radiator cap. I discussed it with a lab tech where I work and there conclusion was that it as it actually lifts rust that is formed by oxidation (only happens in air presence aka low coolant) - the mud is actually the lifted rust. The gelling is not rust - that is usually adulterated coolant (GM plastic gasket syndrome anyone?)

I have seen this coolant being used in Asian countries - infact if you just pour this into a previously rusted system and drive around the engine will become clean but the coolant will become mud - drain and be amazed at the newish looking engine after the initial flush. You might have sprung leaks anywhere there was corrosion.

IMO - BASF Glysantin G05 (zerex G05) is pretty good all round. I have also heard that using Shell LLC or Final Charge LLC is a step up for our diesels.

i wouldn't use dex cool in a gm car

Quote:

Originally Posted by oldsinner111 (Post 3274140)

i wouldn't use dex cool in a gm car

I will never need to make that decision.

I used it at a 40% concentration in a hydronic heating system for years. It has a better specific heat than conventional EG. It was in the system for probably 15 years and looked great when I drained it. However, there were no aluminum or gaskets in the system. Never had a circulator problem and the inside of the boiler was like new.

My signature car has always gotten official MB coolant until the last change when I went to NPG. I don't see the purpose of saving a couple of dollars a gallon on coolant and the risk of problems it entails.

Quote:

Originally Posted by Zulfiqar (Post 3274138)

Dexcool is not suitable for systems that have an "air pocket" expansion tank like our cars - it will cause some trouble (very little because the tank is plastic)

On other cars with radiator caps on radiators and separate expansion tank (system chock full of coolant) this works perfect. This failure usually shows up with low coolant level in the radiator and also due to the "loose valve" radiator cap. I discussed it with a lab tech where I work and there conclusion was that it as it actually lifts rust that is formed by oxidation (only happens in air presence aka low coolant) - the mud is actually the lifted rust. The gelling is not rust - that is usually adulterated coolant (GM plastic gasket syndrome anyone?)

IMO - BASF Glysantin G05 (zerex G05) is pretty good all round. I have also heard that using Shell LLC or Final Charge LLC is a step up for our diesels.

Actually cars with pressurized complete systems, like the 617.952 is ideal for dex. It is a function of a few things, primarily use in engines not designed for it that is the problem.

My saab has a system like my w123 300CD and no issues.

My 240D doesnt even have an overflow...

And my 98 chevy, a vehicle not designed for dex, but that got it from the factory, is spotless. As is the saab (also dex from the factory).

Mixing is no good, especially with silicate AFs.

But I dont get it why it is so difficult to just get the right stuff. G05 is fairly ubiquitos and the same chemistry as the MB coolant.

All my cars are spotless, all original, and get the right stuff. My MBs get MB/G05, my BMWs get G48/BMW, my GMs get dex, VW gets the right G12, etc.