water temp

[telletubby]

E300 W124 Estate runs at 80 without aircon but if the outside temp is about 25 and aircon rises to 100. If outside temp is above this, say 30/33, then temp rises accordingly. Is this normal? i worry that she's exceeding 100c.

 

[turnipsock]

It does happen, but it shouldn't.

I had similar problems with my 320CE.

Eventually, put in some pretty aggresive cooling system cleaner. However, this cleaned out the seal in the water pump so I had to replace this.

After that, the cooling system worked like I would expect.

I don't know if it was the new pump or if the cleaning stuff did its job.

The aircon I have is the aftermarket one and not the proper MB one. When this was fitted, a lot of the cowling that should have been around the radiator was removed.

 

[Andy Cottrell]

My E300D Estate (1994, 606 engine) also ran too hot ( or so I thought). In normal use (10 mile commute, A roads, motorway, then loads of slow/stopped traffic) it would run at just above 80 until you sat in traffic when the temp would rise towards 100. Doing the same run with the Aircon on would see the temp at about 90 until sitting in traffic where it would rise to about 110.
Carried out the "carrot test", noting that the viscous fan was not working. However, a special tool is required to remove this which my stealer wouldn't sell me so this got left.
I replaced the thermostat. This made little difference.
Added resistors to the aircon fan temp sensor at the front of the head to switch the aircon fan at a lower temp. This improved things but on hot ( for the UK) days , 25-27 C, the temp would still be about 100 when sat in traffic with the aircon on.
Changed the radiator as it appeared to be blocked about of a third of the way up from the bottom. ie/ it didn't radiate the heat uniformly. Was told that this is a common occurance as the core is aluminium, and that over time they get blocked.
This improved matters even more, however, to be fair the outside temps had only been about 20 max so far.
Finally changed the viscous fan ( without using the special tool).
Outside temp has only been 24ish so far ( well it is only May) but the car now does not get above 90 with the Aircon on sitting in traffic after a blast down the motorway.

Hope this is of some help.

 

[kanda]

Normal operating temp should be from 85c to 90c

 

[telletubby]

Thanks everyone. I'll try all these in turn. have to say my problems don't really become evident until the temp goes into the thirties ( I live in southern France)