E300D 95 cooling problem?

I have a 95 124 E300 D aut. (Certified/approved to tow up to 1,9t). Under normal driving circumstances I have no cooling problems - temp. is around
85C. When Im towing my caravan (1,3 t) my cooling water temperature immediately increases to 100-120C. The thermostat is OK (checked) - engine is otherwise OK - not that worn.Normal engine oil consumption. Anybody knows why? Could it be, that the aut. transmission fluid is being cooled (integrated) in the water cooler?
Regards,
Jens
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Whenever you do heavy towing it is best to add another transmission cooler... it will extend the life of the transmission and reduce the wear and tear on engine... have you checked if you have enough tranny fluid?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
There is already a standard transmission oil cooler. But it could be an option. it ought to be able to cope with the temperatures. And yes, the tranni fluid is right at the check mark and the colour is also OK.
Could it be the engine oil that needs a cooler. I havent checked whether it is equipped with such...
Thanks for the advices
Jens

... have you checked if you have enough tranny fluid?

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Pulling a trailer makes the engine consume a lot more fuel and the radiator needs to shed the unused / wasted BTUs in that extra fuel so there's no wonder that the coolant temperature is higher than driving w/o the trailer.
I wouldn't be concerned about it so long as the temp remains below 120 degrees C.
You can clean the radiator's outside with a garden hose and nozzle or remove it and have the inside passages and the outside coils professionally cleaned by a radiator shop.
Of course, the electric radiator fans - which you didn't mention - should run when the coolant temp. exceeds 100 degrees C. Do they?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I know - and agree. I dont know the abbreviation BTO - please explain :-)

Why not. This is still a pretty high temperature. If Im going on vacation from Denmark (where I live) to Italy (round 1500 km) it is a lot of engine running hours with a temperature round 30C degrees over the normal.

Agree - some of the inside passages might be blocked. Ill try to flush and clean the entire cooling circuit in near future just to eliminate this option. Otherwise it needs a new cooler - but from outside it looks in fine condition.

Yes, the normal cooler fan as well as the a/c fan works correctly
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Yes, the car runs hotter when towing because it's working harder and the Tranny oil most likely does also go through the radiator. If your car has an oil cooler it should open and start cooling the oil at about 110C so as long as your temperature is around there (not over 120C) the car is working correctly.
Marty
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
This could be the - or one of the - explanations
Thanks
Jens

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Is it normal that a diesel engine - even when running in the best torque interval - produces a relative more heat than a gasoline engine?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Correction: Is it normal that a diesel engine - even when running in the best torque interval - produces a relative more heat than a gasoline engine when under pressure / towing circumstances ?

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I also have a Citroen Xantia 2,0i, (gasoline) automatic (no tranny oil cooler). This car hass less torque even at a higher RPM than my Mercedes. The Citroen needs to kick down more often when towing the same caravan/trailer at 85-90 km/h, but the temperature seldom increases - even in hot weather 30C - with more than 5-10C.
Anyone with a good explanation on the difference in behaviour between the Cit and the MB??
Jens
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The Xantia 2.0i 8 valve engine has its maximum torque of 178 NM at 2700 rpm. So it is not very promising to rev higher. Altogether the engine appears less powerful than it is, most Xantia engines have quite a bit more Oomph. I have a Xantia 2.0i and a BMW 325i with 230 NM of Torque and 170 HP. The Xantia feels less powerful than the BMW, but as a matter of fact it is only slightly slower.
Frank
--
please replace spam-muelleimer with fk-newsgroups for e-mail contact

Citroen - Made in Trance
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.