Thermostat and coolant question
 

Lately my temp gauge has seemed to show that my car is slow to warm up. It doesn't overheat it just take a while to get up to temp. Today after a short trip it was still reading 60c. It eventually reaches 80-90c. I felt the upper radiator hose and it was quite hot. I believe this indicates the thermostat is not closing all the way.

Second question: I am going to buy the Zerex G-05 for my C230. I figured I could also put it in the old truck (1988). However the bottle said this stuff is only for 1996 and newer vehicles. Could this possibly harm an old car/truck? Like maybe it is good for aluminum but bad for copper/brass?

Thanks,

Mike

I think you are right about the termostat. It's a cheap fix.

I'm getting ready to change the coolant on my '81 300 SD. From all that I have read here, I was going to put in the Zerex G-05. How can it be that it's not recommended for cars earlier than 1996, or is that just for American built autos?

Well I just looked at the Mfg specs:

http://www.valvoline.com/pages/products/product_detail.asp?Product=10

They seem to indicate it is good for everything although they don't come right out and say that. But they say it is good for all metals and they have some test data. And the specs say it is yellow, so I imagine that means bright yellow, not the usual MB pale straw yellow.

Mike

Well I changed the coolant and the thermostat. Now the temp gets to about 85 C vs about 70 C before. I have a hard time believing my MPG will improve any since I was getting 31 in mixed driving already. I thought when I took out the old one it would be partially stuck open but it was not. Maybe the spring got weak?

The G-05 coolant is the same color as the OE, straw yellow.