I have noticed through other posts. DO NOT use Prestone "Green"
After spending about an hour at the store compairing different coolant formulas, and reading the posts to look for certain things
not to put in my MB. Is Havoline Dexcool or other "red" coolants ok for my MB?

Does any one know where the AC control module is located for a 98 SL500. I have to pull the fuse so the blower motor will not kill the battery. And is it an DIY replacement.

Thank you

I beleive that these so called requirements are bogus! I have used Prestone in my old 1977 450SL and (I dont necessarily reccomend same) I havent changed or added to Prestone in 5 years except for nuetralizer (also prestone). I beleive that m/b and some others are trying to "push" their more expensive (not better) coolant for additiona profit. Just my 2 cents worth. Abe G

Zerex G05 meets the MB spec and is essentially the same as MB coolant you can buy from MB dealers. It is known as a "hybrid". The corrosion inhibitor package is basically an organic formulation, but has a very small amount of inorganics.

Dexcool is a pure organic formulation.

All these anti-freeze blends are ethylene glycol based. The difference is in their corrosion inhibitor technology.

Both Teaxco (Havoline) and Prestone make a Dexcool formulation and this is indicated by the word "DEXCOOL" on the label.

If you can find Zerex G05, I would recommend that as a first choice and Dexcool as a second choice.

A 50/50 mix of antifreeze and water will provide maximum corrosion protection, freeze and boilover protection. Though potable drinking water is acceptable to mix with antifreeze, I always use distilled water to avoid introducing even very small quantities of disolved salts, which are present in all drinking water.

Duke

One difference is the pH but I don't think pH is listed in the specs presented in the label.

I've heard stories both ways - people who have nothing to gain either way, some say green coolant is okay, some say use MB only. What I know is that the block and head of my 91 300SE looked terrible after having green coolant in it. Certainly worth $5/year to me to keep that from happening again.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

Conventional antifreezes with inorganic inhibitor chemistry are formulated with "reserve alkylinity", and you can use pH test strips to test if the inhibitor package is excessively depleted. As the inhibitors are depleted, the solution becomes less alkyline.

The organic inhibitor package of Dexcool has a different range of pH, and pH is not a valid test of coolant condition.

Not sure about the hybrids, but their pH range is probably different than conventional inorganics, so I doubt if the pH testing is valid with them either.

Duke