Khan28

I know this topic has been discussed a million times on multiple MB forums but there's one issue I can't seem to find any information on. The engine ran somewhat cool all winter long (around 80c according to the dial) and the CEL came on today and when I plugged my cheapo Innova scanner it showed P0128. I've located Wahler thermostats on various parts sites but they're all 100c thermostats.

Could somebody confirm if that's the correct part or should I keep looking for a 90c thermostat. Could somebody please direct me towards a 90c thermostat online?

Also, the mods can delete this post once the proper information has been had since there's tons of posts on this subject.

Thank you for your time!

Khan28

Also, can I use Zerex G05 at Wal Mart to replenish what coolant is lost when I change out the thermostat or should I go for the stuff at the MB Dealership which is 1/2 jug of water for $30?

samaritrey

Dealer coolant is actually 100% coolant you have to mix it yourself but that's all I would recommend using

SunnyRayToronto

MB coolant is really Zerex G05. Get the jug at walmart for like $17,..... Black cap as I recall.

slammer111

All info is here.

https://mbworld.org/forums/c-class-w...sor-tstat.html

The only version available now is 90C, and the part # is now 271-203-05-75.

**update** Sorry, I thought you had a M271 (2003-2005). Didn't realize you have a 2006, which has a M272 engine. Not compatible. My bad.

Glyn M Ruck

You have two different types of thermostat fitted to Benz. On older engines M111, M271, M112 & M113 are conventional 90 degree thermostats. On M272 & M273 onward you have the so called "100 degree" 3 plate, 4 way, electronic thermostat that controls temperature between 85 & 100 degrees C & costs considerably more.

Khan28

Ohh so would this Wahler (first on on the page) unit be the correct one?

http://www.partsgeek.com/catalog/200...hermostat.html

Also, will the engine run at the normal 85c or so with this thermostat installed? Also, since the temperature is now above 0c here the engine is now operating at the correct but since the CEL came back on after turning it off I guess I should still change it.

Khan28

Isn't that for the Kompressor I4 or would it also work for the M272 V6?

Glyn M Ruck

Not for M272.

Khan28

So I can install a 100c thermostat and the engine will run at the normal temperature that it did from the factory right? Just need to know this and I'll order one. This looks to be a pretty easy DIY since there's good space to work in with the V6 motor.

Glyn M Ruck

Yes. You can install the electronic thermostat. Just remember to connect it to the ECU. The darn things are expensive.

Glyn M Ruck

Operation:

Khan28

Oh ok thanks. I'll go ahead and place the order. I remember changing the thermostat on my Mom's Mazda Protege a few years ago and if memory serves correct the price for the thermostat was $11 and a jug of Prestone coolant was $9 but for the Benz it'll be around $100 for the thermostat shipped and $17 for a bottle of Zerex G05. Oh well once I do this I won't have to worry about this again.

slammer111

Wow, that is one fancy thermostat for the m272 - holy geez.

Quick search on RMEuropean shows it for sale for $97, part # 272-200-04-15.

Good luck.

Khan28

Haha yeah but I reckon it'll be easier to replace on this car than it would be on a BMW because a BMW has a ton of cheap plastic cooling pipes under the hood. For the Benz it's right next to the oil cooler housing.

Khan28

Alright so I went ahead and placed an order but just for the heck of it I decided to check what type of coolant my car has. It has the pinkish/peach type coolant. Is that Zerex G05? I know of MB blue coolant but not of a pink type which is in my car.

Khan28

Also, is it possible the temperature sensor has gone bad too? What if the temperature sensor were to fail and the engine was overheating but it's showing normal on the needle is there some sort of backup warning? I mean I can smell if an engine is running too hot as I have with other cars so I know mine is running properly but if the temp sensor kicks the bucket what happens after that?