[Jeeringtowser]

My 2004 SLK200 Automatic does not get above 70 degrees, even in slow moving traffic it fails to reach 80 degrees. I assume it should be in excess of 90 degrees!
What temp does everyone else's run at?
Hoping for a reply.
Chris:grin:

 

[Windwalker]

My R172 runs at about 90.

 

[Jeeringtowser]

I thought that they should.
I suspect a faulty thermostat
Thanks
Chris

 

[Hal Adams]

Do not rule out the sender unit though - in fact many will change the sender along with a thermostat as a matter of course, and as they are a doddle to put in, many try this first. But probably right that it is a thermostat open.

 

[Beppi]

Had the same problem check the link, http://www.slkworld.com/slk-r171-ge...-celsius-when-driving-slk-200-2005-model.html You must change the thermostat check the attached photo, the old thermostat was stuck open. Very easy to do without spilling a drop of coolant water if you do as I have done, check my link.

 

[Beekster]

Hal & Beppi are right; it's almost certainly the thermostat that's failed in the stuck-open position.

One thing strikes me as odd with you guys running the SLK200...you don't get a CEL lighting up with this, do you? On my SLK280, when the thermostat failed it threw a CEL. It doesn't make sense to me that one engine family lights up a failure indicator and another does not; Mercedes is usually more consistent than that.

 

[Beppi]

Hal & Beppi are right; it's almost certainly the thermostat that's failed in the stuck-open position.

One thing strikes me as odd with you guys running the SLK200...you don't get a CEL lighting up with this, do you? On my SLK280, when the thermostat failed it threw a CEL. It doesn't make sense to me that one engine family lights up a failure indicator and another does not; Mercedes is usually more consistent than that.

If the thermostat is stuck open there is no warning from the cel, there is no danger driving with an engine temperature between 70C and 90C degrees. I drove quite q while before noticing the temperature was low. However the car responds better now at 90C degrees.

 

[Beekster]

If the thermostat is stuck open there is no warning from the cel, there is no danger driving with an engine temperature between 70C and 90C degrees. I drove quite q while before noticing the temperature was low. However the car responds better now at 90C degrees.

Agreed that there's little danger of overheating with a stuck-open thermostat, and not surprised that the car runs better when it gets to the proper temperature. What mystifies me is why my M272 V6 SLK280 is programmed to throw a CEL when the thermostat fails, as mine did last year, and your M271 I4 SLK200 does not. There's no reason that I can discern why the two engine management systems should respond differently to the same failure mode.

 

[Beppi]

Agreed that there's little danger of overheating with a stuck-open thermostat, and not surprised that the car runs better when it gets to the proper temperature. What mystifies me is why my M272 V6 SLK280 is programmed to throw a CEL when the thermostat fails, as mine did last year, and your M271 I4 SLK200 does not. There's no reason that I can discern why the two engine management systems should respond differently to the same failure mode.

I think that car has a different thermostat with different compartments. I also has a heating element to heat up the thermostat so it will open. Much more evolved set up.

 

[Hal Adams]

What mystifies me is why my M272 V6 SLK280 is programmed to throw a CEL when the thermostat fails, as mine did last year, and your M271 I4 SLK200 does not.

- one powered the Ark and the other is a new design..:smile:

 

[Benzoid]

"Who would have thought that a nuclear power plant could be so complicated!" -- Homer Simpson

Looking at the cooling system in the R-272 with its electrically controlled multi-plate thermostat, separate recirculation pump, & washer fluid heat exchanger, I am reminded that German engineers are the only people in the world who use 5 lines to draw a triangle.:laugh:

 

[Jeeringtowser]

"Who would have thought that a nuclear power plant could be so complicated!" -- Homer Simpson

Looking at the cooling system in the R-272 with its electrically controlled multi-plate thermostat, separate recirculation pump, & washer fluid heat exchanger, I am reminded that German engineers are the only people in the world who use 5 lines to draw a triangle.:laugh:

You are quite Reich:laugh:

 

[racing_green]

I'll piggyback that thread.. it looks fresh ;-)

My new toy (R171, 200 kompressor, 2004) never reaches more than 50 deg C - I guess thermostat stuck wide open is not unusual? I didn't have time yet to check if the radiator gets warm shortly after start.

 

[i860]

Is a simple job, plus the part is 16-18 pounds only.
This is from c class same engine like slk 200
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