How long for the engine to get up to temperature? W204 C200 cdi auto

[KLipswich]

Hi new (returning?) member here

Just bought a 59 plate C200 cdi Auto Elegance, it takes approx 8mins to get to 80 and then at around 10mins+ the thermostat opens at around 90 and temperature come back down a little. Does that sound a bout right? Fuel mpg is poor while it's cold (low 30s mpg) but fine when it's warm 55-57mpg with cruise on at 70mph. Idle speed a little lumpy EGR? TIA

 

[W1ghty]

Hi new (returning?) member here

Just bought a 59 plate C200 cdi Auto Elegance, it takes approx 8mins to get to 80 and then at around 10mins+ the thermostat opens at around 90 and temperature come back down a little. Does that sound a bout right? Fuel mpg is poor while it's cold (low 30s mpg) but fine when it's warm 55-57mpg with cruise on at 70mph. Idle speed a little lumpy EGR? TIA

That sounds very similar to the new stat I fitted on my E320cdi the other month .

 

[Stratman]

Thermostats are a known cause of trouble on many MB models including yours. The symptoms you describe point squarely in its direction. A new one should see you sorted.

 

[m80]

A replacement stat didn't improve things on my 651. I'm assuming as a 204 yours will be 651.
We are supposed to adapt the new stat heater element to the ECU, done that.

In cooler times mine can take 20 miles and more to get to above 80,
today it was there in 2 miles.

 

[Benzowner]

Diesel engines run cooler than petrol and therefore take longer to warm up. There is no problem with your thermostat as engine temperature is taken off the engine and the thermostat allows cool water from the radiator to enter the engine when it get to operating temperature. If your temperature gauge reaches temp and the thermostat opens you have no problem, it is when the temperature stays low all the time points to one aspect of a thermostat failure.

 

[KLipswich]

Thanks, I had a problem with an E270cdi years ago and that just didn't get warm, changed the stat and it was fine. Current car just seems really thirsty when the engine is cold. Wondered if a slow warm up is a warning of a stat on the way out ie not closing properly as they seem to fail open rather than closed?

 

[W1ghty]

Thanks, I had a problem with an E270cdi years ago and that just didn't get warm, changed the stat and it was fine. Current car just seems really thirsty when the engine is cold. Wondered if a slow warm up is a warning of a stat on the way out ie not closing properly as they seem to fail open rather than closed?

Poor performance mpg wise before The car warms is normal . I changed my E thermostat recently for £34 . If you are second guessing the stat and it’s original and it’s cheap just change it .

 

[W1ghty]

Thanks, I had a problem with an E270cdi years ago and that just didn't get warm, changed the stat and it was fine. Current car just seems really thirsty when the engine is cold. Wondered if a slow warm up is a warning of a stat on the way out ie not closing properly as they seem to fail open rather than closed?

If you don’t know already you have an excellent MB Specialist in the form of Alex Crow in Stowmarket.

 

[Tonygw]

All sounds very normal to me. Mine is the same, has been in the 3.5 years of ownership..

 

[johnsco]

The OP's car sounds OK to me.
When I bought the Kompressor, it was slow to warm up and the gauge never got above 60 degrees.
You could smell the petrol as the engine was running far too rich all the time.
The heater was never really warm.
I changed the stat ... An easy job and not expensive.
The old stat was stuck fully open.
Problems cured.
The car now warms up quickly to between 80 and 90 and stays there whatever the weather..
Simples !

 

[KLipswich]

If you don’t know already you have an excellent MB Specialist in the form of Alex Crow in Stowmarket.

Thanks, yes I know Alex and this one has been looked after by him for some years now.