An old thread I know, because I posted in it a few years ago, but did not feel the need to start a new thread on my question and have read through this until my eyes are crossed.

I have a newly acquired 1988 Mercedes 300SEL, which appears to be a very well maintained car. Engine bay is clean, but not too clean (as if it had been cleaned). Fluids are clean, etc, HOWEVER it has the dreaded GREEN coolant in it, which is a no-no I know.

The car runs in the normal range... @ 80°C (when stopped) or slightly below when on the highway.

I want to get MB coolant in, but wondering if I should leave this to a professional, such as the dealer and will the green have to be flushed and is there a chance it could clog my evaporator core or damage my headgasket, etc? Like the old saying goes, if it aint broke, dont fix it, but I do not want the green to damage anything. The car is 20 years old and Lord only knows how long the green coolant has been in there.

I contacted a local MB mechanic (but specializes in diesels, but does general work on gassers) and he said he also recommends a thermostat change. His reply was:

"Your 103.981 engine has aluminum heads and brass in the radiator so it is best to switch over to ZEREX G05. In time, the standard "green" antifreze could cause problems with key components like the heater core, radiator, and water pump, because of the way it reacts with the metals it comes in contact with. ZEREX G05 has longer drain intervals than standard coolant".

Sounds like he knows what he is talking about. Does anyone else use this coolant or should I go ahead and use MB coolant? If prices were identical, would the dealer be the best to do this or would any MB independent shop be OK for this? He said he flush/change the coolant for $55 (labor).

Thanks in advance.