I have a '92 300SE (W140) with the 3.2L engine. During the winter the coolant temp gauge used to read approx. 80 degrees C. Now with the warmer weather the guage is running approx 90 degrees C.

1. Is this normal or should i change the thermastat?
2. I've seen other posts recommending drilling a hole in the thermastat, is that an appropriate fix as well?
3. Will i need to bleed the air from the coolant system if i change the termastat? If so, is there a special proceedure?

Thanks!

You must be used to Japanese cars. You coolant temp gauge is accurate, and reads the changes in coolant temp for real. Neat, huh? Most Honda, Toyota, etc. are non-linear to make you think your coolant temp is "constant."

It is not.

In your car, your normal temp range is from 80C or so to about 100-105C. Don't be too alarmed in hot weather with the AC on full if your temp gets slightly over 100C. In every MB I've owned, this was normal behaviour.

BTW, there is a huge amount of info in the archives. You might want to try searching...

__________________
John Shellenberg
1998 C230 "Black Betty" 240K

http://img31.exs.cx/img31/4050/tophat6.gif

Thanks for the info and the quick reply!

Bob

If anyone feels compelled to drill holes in a t-stat, why not just remove it altogether? The thing is intentionally designed to open and close. The flow remains open with holes drilled - all of the time.

A thermostat not only controls the heat, it also controls the flow of coolant.
That's why you can actually create an overheating problem, when you remove the thermostat.
The coolant flows through the rad so fast, it does not get a chance to cool down.
Some engines, ( my former 5.0 Mustang comes to mind ) have a little ballcheck valve in the thermostat. The purpose is to prevent steam pockets from forming in the cylinder heads, especially after a coolant flush/re-fill.

__________________
2007 C 230 Sport.

I wouldn't modify the cooling system on a W140 300SE. No need. If the car is overheating (120C) then repairs need to be made.

A few MB cars, a very few V-8 models do run a tad warm, and there is a fan mod that works well.

Otherwise, in the other 95% of MB cars, leave it alone.

__________________
John Shellenberg
1998 C230 "Black Betty" 240K

http://img31.exs.cx/img31/4050/tophat6.gif

blackmercedes-----

I've heard of fan mod on v-8's.
For 4.2L?

further info?

thanks