Thermostat on its way out?

[Jukie]

MY2011 W212 E350 CDi.

For a number of months now my thermostat has not risen above early to mid 80 degrees ever, regardless of external temperature or workload.

Additionally, on my homeward journey which consists of about 1 mile urban, about 20 miles cruise up the M6 and then 6 miles clear A road before home, it will occasionally be a good 10 miles up the motorway before the temp gauge edges up to 80 degrees and then beyond. Doesn't seem to be quite so prevalent on the outward journeys, mind.

Time for a new thermostat? I understand it's not a major job.

TIA, David.

 

[cheddar]

Sure sounds like it. I would get an OEM one if possible (usually WAHLER), but if you haggle with MB parts dept, a genuine one can sometimes come in at a very similar price to a quality one from elsewhere.

 

[OneForTheRoad]

My c250 takes an age also to get up .i did read on ecp website the stat opens at 95 degrees. Both my w219 and w211 opened at 90 and didnt take 5 miles to get there...

 

[DaveE320CDI]

About £130 if i remember correctly from Merc, and difficulty depends on which turbo boost pipe is fitted? if like the one i had then its a real pain, problem with getting the third bolt out because of fuel pipes etc in the way,
hope yours is the easier one

 

[markjay]

On fast A Roads and Motorways, the engine cooling is actually very efficient.

You really need to check this with the engine idling - or while driving in very slow stop/start city traffic - that's when the coolant reaches peak temperatures due to lack of airflow through the radiator. If all is as it should be, then you should see the temperature gauge slowly climbing into high 80s and 90s and hear the fans cutting-in, before the temperature drops down again.