chazman

Last week I flushed the cooling system of my 2006 C230 and filled with fresh coolant. In the process I accidentally put too high % of coolant - like 90% coolant and 10% distilled water (maybe even higher!) instead typical 50/50.

I've been driving like that for a week now, and I don't see any obvious problem yet. The engine operting temp indication on the dash gauge is normal as before (at mid point or slightly lower).

Do you think the extended driving with near-straight coolant will cause anything bad to the engine or its cooling system?

Glyn M Ruck

Glycol is not as good a heat transfer medium as water. In hot conditions too much coolant will make the engine run hotter. I would correct the ratio with conventional coolants.

chazman

Not sure if the coolant I used (Premium Prestone 150K mile guarantee) is Glycol or not. But the packaging says it can be used for ALL models and mixed with ALL types of coolant (if just adding).

What is the conventional coolant made or consist of if not Glycol?

Glyn M Ruck

Prestone is Glycol based.

Today you get some chemical coolants that you use 100%. They contain no water & cost a fortune.

mis3

I read somewhere that MB coolant is excellent. Not sure about Prestone.

I also read that one should not mix different brands of coolants. Is this true?

Glyn M Ruck

MB longlife coolant is excellent.

Mixing coolants can cause gel formation.