No/Little heat Merc ML270 CDTi

JohnDavies

Active Member
Joined
Feb 28, 2017
Messages
131
Location
Ripon, N. Yorkshire
Car
ML270cdti & C200 Coupe
Firstly thank you for allowing me to join this fantastic club. I have a small problem ( i hope) in that when my engine is up to max temp i only get cold air in the cabin. Yet if i stop the car and park up for 4/5mins then restart the engine i get luke warm air even though my temp setting is at max. Could this be a sticking thermostat or maybe something else. Any comments would be greatly appreciated. I have purchased a new thermostat in anticipation and will get that fitted but should i be looking elsewhere anyway?
 

Stratman

MB Enthusiast
Joined
Jun 15, 2003
Messages
4,970
Location
Sunbury
Car
W203 C200 CDI '04Estate
The thermostat is a known weakness on many MB engines including yours and is the first port of call when there are any heating or running temperature problems.

What temperature does your engine run at? Does it fluctuate between traffic and the open road?
 
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JohnDavies

JohnDavies

Active Member
Joined
Feb 28, 2017
Messages
131
Location
Ripon, N. Yorkshire
Car
ML270cdti & C200 Coupe
Temp rises to just under 80 degrees and does not fluctuate. Just seems strange that i have to achieve this temp or just below it and have to turn off the engine for a few minutes then restart and presto some heat although only just warm heat. Had thought at one time i may have an airlock???
 

Stratman

MB Enthusiast
Joined
Jun 15, 2003
Messages
4,970
Location
Sunbury
Car
W203 C200 CDI '04Estate
80 is a bit low, it should be 90ish. It gets warmer after you switch off for a few minutes because the latent heat in the block heats the water a bit.

Change the thermostat, it's an easy enough job. Just be careful of the plastic fuel pipes which run close to it, they can get brittle and crack.


The holes in the housing for the brackets attached to it are not threaded, you use the screw to cut one as you drive it in.
 
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JohnDavies

JohnDavies

Active Member
Joined
Feb 28, 2017
Messages
131
Location
Ripon, N. Yorkshire
Car
ML270cdti & C200 Coupe
Thanks for that info i shall be aware of it now. Brilliant club/members.
 

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