mbpharoh

Today I had a friend of mine check the check engine light that I had. It's been on for the past two weeks and prior to that it was on for a few days and then went off. The code he got was p0128. It says engine coolant temp a ture or thermostat... If it was the thermostat wouldn't my car over heat? Or maybe it's just running bad ? Any suggestions on what I should do

malcozrog@yahoo

my engine light's on for two weeks every since outside temp dip below 0; diagnostic code came back as PO128; ---> "coolent temp below operating range"... and on some days after driving 20 minutes there is warmth on the side of console but not everyday

mbpharoh

I'm guessing it has to do with the snow that we had that threw everything off once it warms up I'll erase the code and see if it pops up again.

Austinglen

I had a CEL as well and pulled the same code. Just because your car is not overheating doesn't mean your thermostat is not messed up. Mine just so happened to be stuck in the open position. You will need a new thermostat.

malcozrog@yahoo

thank you

jpflip

Just had this failure and realized the temp was lower than normal about 80 C instead of 95. Had to replace the thermostat. $112.00 and did the job myself which is not difficult….

mbpharoh

Do you guys have the part number for the thermostat and is there a DIY out on how to replace it?

jpflip

The part# depend of your Vin# but it can be 2722000415. There are two good sources of information which is a video and a pdf: https://mbworld.org/forums/c-class-w...w203-c280.html and . Of course the pdf is a W203 but very similar to the W204…In my case, I've never found the radiator drain plug and decided to let it drain from the thermostat housing….One gallon of coolant was sufficient since you mix it 50/50….

mbpharoh

I appreciate the link to the pdf and how to. Do you know if driving like this for another few more days can mess anything up? Until the weather clears up for me to install it

jpflip

No problem to drive with a stuck open thermostat. If your temp is lower than normal it will affect you fuel consumption more than anything else. But if your thermostat is stuck close that can be a problem because your engine will eventually overheat. Keep an eye on the temp!

mbpharoh

So the two dealers around me are charging 160-180 for the part dose that sound right?

Pete7874

I'm seeing it for under $100 online. The dealer obviously throws in their mark-up. Not unusual. Anything you buy from the dealer will be overpriced.

jpflip

I've paid $119.72 at ECS tuning.

Pete7874

You will eventually get excessive moisture and fuel contamination in your engine oil as the temps aren't high enough to burn them off. Don't wait too long as this can cause permanent breakdown of your oil and you will need to change it.

RavenMDX

Well, the engine light came on for me as well this morning. 5 mins later I was at the dealer. Thermostat failure. Seems like a common problem after a few years and happens especially during the harsher winter months. It explains why my car temp was running low in the past 2 weeks and I had low heat in the car.

Some work I do myself but this time I had no time. I went to an indie benz shop. Total cost (tax in) was $528 which includes thermostat, labor, star diag reset, new coolant.

Critter

528.00 You should have taken him and his wife out for steak dinner after that, what a deal!!!
Should have been no more than 200 with a car wash and inside vacuum.

RavenMDX

hehe yeah I hear ya

well, I knew it was going to be a few hundred. The breakdown they gave me is as follows:

thermostat with housing $195
coolant $22
star diagnostic and reset $107 (yikes)
labor $135
wash $0
tax $68 (tax is crazy here)

total approx $528

Pete7874

What is that? Clearing fault codes in the ECU? What a ripoff. Sorry to hear that you were taken for a ride.

RavenMDX

...

Critter

I might have jumped the gun, all seems good except for the fault code/reset, probably took 1 minute. Dealer does for same price, but oh well it is done.
Actually a lot better to have low heat so the stat fails open than to have it fail closed and overheat the engine. Seems to be a common issue with these thermostats.
Do you not have 13% tax in Montreal? or is it 15%

jpflip

Just realized you were from Montreal! I did this job on my car last week and it cost me total $170.00 and did the reset with a generic Innova OBD tool that I bought at Canadian tire… Got robbed lately by Silverstar Mercedes dealer in Montreal, they will never see me again for anything!!!! I am sorry for you….

RavenMDX

its closer to 15% now...

RavenMDX

very nice. well I knew It was going to be more expensive but now I can see that I got screwed. The worst part is that I didn't even go at Silverstar (it would of been even more expensive!). I went to exclusive mercedes about 3 block from there which caters to out-of-warranty mercs.

Thanks for the tip on the Innova, I will get myself one too.

Cheers

mbpharoh

Hey guys my check engine light turned off by its self...the heat is blowing out hotter air than before. Should I go back and return the thermostat as I didn't use it or replace it? We had warmer weather than usual today if that helps

jpflip

You better keep it!!!\ You will eventually need it !!!!