1995 W124 E300 nonturbo diesel estate overheating with A/c

[telletubby]

Help! This car is a new acquisition. Driving in temps of 27-32C yesterday the motorway temp was fairly constantly 100. With A/C on this rose higher ( I didn't leave it on long enough to find how high it would go but opened the windows instead). As it was evening the temp went finally down to 90 as the outside temp became 24ish. Still much higher than my W124 E320 cabrio would ever reach.

Coolant level is OK. Today I did the carrot test which passed with flying colours. The only other thing I noticed was that the top rad hose was slightly flatened in the middle - could this restrict the flow? What else should I check? Thanks for any advice.

:-|

 

[telletubby]

Today I drove at 90C+ most of the day with outside temp at 24C until i put on the A/C at which point it climbed over 100 and rising. I stoppede at one point when the radtemp was 110 and the second fan was not working. Is this a thermostat problem?

 

[paulcallender]

When you say it passed the carrot test, does the electro-hydraulic (or whatever it is...) clutch kick in and slice the carrot (run to cool the car)? This fan should be able to adequately cool the car from, say 95 deg C when it kicks in, to 85 deg C or so.

Other things you could do, hmmmm, check the strength and quality of the coolant (the more antifreeze, the less the thermal capacity - so go for 40:60 antifreeze:water in the summer), if anything is unwell here, reverse flush the cooling system and replace the coolant.

 

[OlafMaxwell]

I can say my temperature goes high when using aircon in hot weather as in 30-40c in France. I also have same on Peugeot in similar driving conditions. You do need to watch the temperature and not overheat to much but the rise to 100 is normal enough. Using the recirculation button for a while helps reduce the load as it recirculates the cooled air. The other option is not to overcool the car but in my experience the MB aircon is barely up to the job in the first place. I do know the diesel suffers more of a rise than the petrol engine in these conditions.

 

[Mustang]

try flushing radiator :wink:

 

[telletubby]

thanks for your replies guys. I certainly didn't know that a diesel may run hotter than petrol. Strange thing is I took her for a 26 mile run yesterday without the aircon and she ran at a steady 90 except uphill when it rose to 100 before coming back down ( presumably the second fan kicking in ). But with aircon up up and away......................

I'll try a hot flush.