eddieo45

I did see a couple of threads on this (Clkboi's thread) but is it always a bad thermostat? Reading the list on Autozone's scanner tool, I thought I saw "coolant level," or was that just wishful thinking? BTW, this is for my wife's E350, not that I think it matters.....

Yidney

If it's the coolant level you can tell by looking at the coolant overflow tank.

eddieo45

It was only down a little, so I'm doubting that's it, but I topped it off anyway.

togaclk55

http://www.obd-codes.com/p0128

eddieo45

Thanks toga; anybody have any thoughts as to the timing of this, deep-freeze temps and all?

Clkboi

Ah i remember that code. What is your engine temperature like? Mine stayed a line lower than usual

Clkboi

Also mine was in the winter as well. Very cold when it happened i remember

Rudeney

P0128 = thermostat stuck open. It could be the cold weather, but it could be a stuck thermostat. If it takes more than a few minutes before you have heat in the cabin, then I would replace the thermostat.

Glyn M Ruck

Yep! replace the thermostat. You don't want the car operating cold.

eddieo45

I note that my CLK runs about a line or two over 80°C, so I asked my wife to report her temp in her car, the E350 w/ CEL on: she says it never reached 80° during her 30-40 minute commute home. I guess replacing the thermostat is indicated, $106.80 on parts.com

Rudeney

Yes, 85C is the target operating temperature. You can see it go as high as 100C on a very hot day, but by then, the electric fan should kick in. Some engines don't run well above 90C, so there is a setting (via SDS) to have the fan kick on at a lower temperature to help with this.

eddieo45

UPDATE: the CEL went off, but running temp still (just) below 80°....do I worry, or assume it's fine?

Flame3g

That's a hard one I would replace the thermostat any way or buy it and keep it handy. best of luck

newamerican

Manufacturer: WAHLER
Part Number: W0133-1953845
Description: Thermostat
Thermostat
Is this is wright one for this car?

xsever

The MB part code is 272-200-04-15 and it is a WAHLER part.

newamerican

Here is where I found parts and video:
http://www.fcpeuro.com/products/merc...-2722000415kit