C230Girl

I have a 2005 C230 Kompressor and a few days ago someone had put in 89 fuel instead of 93. Then yesterday the check engine light went on and the code that is showing is:

P0128 Coolant Thermostat Coolant Temp Below Thermostat Regulating Temperature

Is this a fluke thing because the fuel may have shocked the engine or how else do I fix this issue?

LILBENZ230

No it's not fuel related. The thermostat is stuck open and the car is not reaching normal operating temp. You need a new thermostat.. part is about $25-30 and labor might be $100. Don't take it to dealer.

tommy

My guess would be bad thermostat, and that the bad gas has nothing to do with it.

Judging by your post, the best thing to do would be to have a MB specialist in your area look at everything and fix what needs to be fixed.

Glyn M Ruck

Replace the thermostat!

C230Girl

Ok thanks for the advice! The temp sits at 80 and does not over heat or rest below 80.

LILBENZ230

80 is too low. Should be 87-90.

04mbc230

Hmmmz. Mine always is a little pass 80. I am guessing 83 or so.

LILBENZ230

A little past 80 = ~87

C230Girl

Oh ok I didn't know that, thanks

mtnman82

Mine started with staying ~80 when I first had this come up (and I got the CEL), then after a couple weeks it had a hard time getting over ~60. After replacing it heats up to ~85 and stays there. Cheap, easy fix - shouldn't be more than an hour in labor and $50 in parts.

Boom vang

All M271 engines seem to need a thermo after about 5years. I also changed a temp sensor that was throwing codes only when it was cold out side listed the error as 'Coolant' the sensor is on the exhaust side of the engine right near the plastic part (the nipple that attaches to the metal coolant pipe) that always breaks on this engine and is a 5 min job to replace the sensor and plug it in and costs about $20

Glyn M Ruck

Old thermostats opened between 87 & 89. New thermostats open at 90 in NA. They appear to have ceased to sell both.

C230Girl

I'll take it in sometime next week then to have it changed out.

LILBENZ230

Stopped selling the thermostats altogether?

C230Girl

I found this one...is this the right one?

http://europortparts.com/searchitem....u=473232323233

LILBENZ230

That's too expensive. Let me help:

http://www.rmeuropean.com/Part-Numbe..._91DEFFEE.aspx

Or even cheaper:

https://www.getmercedesparts.com/mer...***-parts.html

TexFinn

50 bucks for a thremostat? No way.

Like LILBENZ230 already pointed out, low-30 buck range is where it should be. AutohausAZ has them for $33.xx. Then add $17 worth of other stuff and you'll get free shipping.

Glyn M Ruck

Ambiguous choice of words. They used to sell the conventional & cold climate thermostats. Now they only sell the cold climate 90 deg C one. No doubt for engine efficiency reasons.

LILBENZ230

Yep I see now what you meant.. lol

So it is more efficient to let it run at 90C instead?

Tri-Star

My temperature has always read 80 degrees, however I have a c320 v6 ... don't know if there should be a difference.

Glyn M Ruck

Yep - hotter is better within reason. Eg. VW have long tried to run bulk oil temp at 128 Deg C

Hotter engine & colder inlet air is the answer.

C230Girl

Thanks I'll order it and hopefully the temp reads a little higher then it has been.

nobli

not to hijack the thread, but would that also work on an 07 c230? and would i need to buy the housing separately ? or is it not necessary ?

CoupeCrazy03

Just got this code today Looks like ill have to replace the thermostat. . . anyone have the part number?

LILBENZ230

Uhhh there are links to it all in this thread.