Cooling Problem?
 

The car (95 E300d) usually runs around with the temp indicator at the top of the 8 (gauge) on the freeway and around town, summer or winter. If I turn on the AC it jumps well above the next mark on the gauge for a bit on the freeway, and around town it goes even higher and stays there to the point I think it turns off the AC. If I go up a prolonged grade on the freeway the temp climbs accordingly, but really moves if the AC is on. Freeway driving, over time will get the temp down to the 8 again, AC on or off. Any thoughts? Do have a problem?
I checked the engine driven fan after I parked it, and it is turning.
As we used to say in the B-52.........ops check normal, cannot duplicate, fly as is.



Thanks,

B52Rule

I'm not very familiar with the E300 diesel but I know that mercedes has a very high temperature setting before it shuts the A/C off. Is your radiator getting hot? I would almost think it is an almost stuck closed thermostat. As the A/C shuts off normally a secondary fan kicks on to give every ounce of cooling possible. You may want to try turning your heat on high next time this happens, better to be uncomfortable sitting in the car than uncomfortable walking down the road for help.... Diesels normally cool down on freeway driving and at idle.

some results....kinda
 

If I disconnect the two prong pigtail at the top of the block, key on or off both fans come on high.

If I disconnect the blue with red trace leads to a relay below the drivers headlight the fans never come on. I can ground them out, connect to each other, connect the terminals, or just about any other combination you can think of............no fans at any time.

Any suggestions?

I did check all the fuses BTW.

Am I guessing correctly that when you turn on the A/C, neither electric fan turns on at all?
If this is so, then you would want to check your relays, and if they are good, check the resistor. (a little metal box, with springs in it...the wiring going to it could be corroded too)

Good luck...

-Larry

fixed....I think
 

The 30 amp in the relay fuse is good, but the 15 amp fuse in the relay was blown, I replaced it and the fans come on at low speed, intermittently while the AC is running. This happened just after I fired it up after replacing the fuse. I'll take it out tomorrow and we will see what really happens.
Where is this resistor located?

B52Rule