W210 1995 E200 coolant temp under 70 deg C

The Pilgrim

Member
Joined
Feb 26, 2011
Messages
36
Location
Bucharest, RO
Car
1995 W210 E200 automatic
Hello to you all,

Problem: Coolant temperature rises too slow (20 km trip, 70km/h, coolant temp under 70 degrees Celsius, ext temp cca 7 deg C, town rides means cca 75 deg C after 10-15km at ext temp cca 10-12 deg C).

Checked:
1. thermostat out for inspection, closed when cold, fully open when the water was boiling; conclusion it is working (how good I do not know though).
2. fan viscocouple cleaned and lubricated (break cleaner and WD40), so I'm sure it is not dragging / blocked.
3. summer temps cca 82-85 degrees C, not over 90 even in jammed traffic.

Improvements: cardboard in front of radiator 70% of its surface.

Suppositions:
1. Thermostat opens too quickly - is it possible? The upper water pipe is warm when the temp indicator shows 60 degrees.
2. Radiator too big? Car from Holland runs now in Romania. I do not think so.
3. Instument cluster temp indicator works out of range. Need IR / laser thermometer to check.

Questions:
1. What would be the issue? Is any??
2. I expect fuel consumption to rise - not good at all.

Some old mechanic asked me if the heat inside the car is ok - answerd yes, plenty. Then he told me to leave it as it is. I'm not happy with that. Is a well engineered car and I know the minimum coolant temperature should be 80 degrees C. I do not think MB would leave unattended such an important issue.

Any knowledgeable answer is most welcome, so thank you for your time.

Stefan
 

Dec

MB Enthusiast
Joined
Jul 28, 2004
Messages
4,475
Car
C180,A.
Make sure that you replace the thermostat with the correct rating, I think it is 87°C for your car, your existing thermostat might be the wrong rating for your car, if it is rated lower than 87°C it will open too early.

Dec
 

Stratman

MB Enthusiast
Joined
Jun 15, 2003
Messages
5,001
Location
Sunbury
Car
W203 C200 CDI '04Estate
Checked:
1. thermostat out for inspection, closed when cold, fully open when the water was boiling; conclusion it is working (how good I do not know though).

It's what happens in between those two extremes that governs the running temperature. At what temperature does it start to open? That's the important one.

Like renault12ts said, you need a new thermostat. MB 'stats are not known for their long term reliability.

Welcome aboard from me also.
 
OP
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T

The Pilgrim

Member
Joined
Feb 26, 2011
Messages
36
Location
Bucharest, RO
Car
1995 W210 E200 automatic
Thank you for your kind replies. After I'll replace the thermostat I'll post the result. I wonder if higher temp stats are made (eg. 90degrees, not 87) for this model. I'll check with autoparts stores around.
 
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The Pilgrim

Member
Joined
Feb 26, 2011
Messages
36
Location
Bucharest, RO
Car
1995 W210 E200 automatic
Hi guys,

I ended adding another thermostat (89 deg, cheap) right after the original. Now the coolant temp is 80-85 deg, slightly oscillating.

This smart cheap fix was suggested by a forumist from "clubmercedes.ro", and it proved itself to be a good one.

Thank you again for your input.

Stefan
 

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