salehjm

i have a 1987 mercedes 300E ... at idle the temps increase to max ... i recently replaced the water pump, fan clutch and a bunch of hoses ... the car runs really well otherwise ... oil levels are good, but i noticed that the coolant resevoir thing is always backed up to the rim when running ... also the aux fan in the front doesnt seem to ever go one ... any ideas? all fuses are good, but it seems the instrument panel fuse goes out here and there too. thanks.

TheDoughboy

I would check for a kinked hose, blocked radiator or a bad coolant tank cap.

HTH,

Ron

pifcat2

First make sure you bleed all air out, the water may not be circulating. There should be a bleed hole on top of the water pump.

Check that you don't have a blown head gasket: is the water clear (no oil)?
How long at idle before the head heats up and to what temp? What prompted the water pump change?

The A/C must be switched on and engine hot to run the aux fan.

The auxilary fan has a thermoswitch on the head the diameter of a quarter under the air cleaner. Pull off the double lead and jump them with some wire (with the engine running or battery on) This should run the fan if it's working properly.

salehjm

thanks for the reply ... ok, the water seems clear ... the car increases usually after like 15-25 minutes at idle, and it increases to red line usually ... there is a smell of radiator fluid even in the car when you turn on the heater or just at idle ... it was last winter during school and i noticed my steering becoming stiffer and stiffer, then the water pump started leaking and then just **** the bed ... replaced that and the drive belt... also, my a/s doesnt work, never has since i got it ... never really checked into it.

YNVDIZW124

There is a leak somewhere and maybe you radiator is about to go. Im not sure but it can also be your thermostat that is rusted shut and making the temps go up.

pifcat2

Check the aux fan switch first. These cars don't idle cool without this fan. Mine will overheat if it's not moving over 25MPH without the fan...

salehjm

do you mean the Aux. Fan Resistor because i dont know what the switch is or where it is ... can you get me some more info? thanks a lot. i want to spend sometime in the engine tomorrow with things to look for.

shadowgriffen

the aux fan is really hard to tell if its on or not so...what you do is just run the car for a while, I don't know joy ride or something, park somewhere (DUH!) and shut it off. Turn the key all the way so that you wont start the car but all your lights flash on and that annoying buzzing sound comes on, get off the car, lift the hood and check to see if its running or not.

that will tell you for sure if it runs or not, it will keep running even if the engine is not on...

PS: I'm from beantown too

pifcat2

The thermoswitch I described earlier on the head under the air cleaner. jump the double connector and it should run, bypassing the switch. If it runs and the engine is up to temp ~100 degrees, then the switch is bad.

BTW, you can tell if the aux fan is running by looking at it turn! Yes it must be warmed up enough for the thermoswitch to turn it on.

You should also inspect the belt driven fan since it is a fluid clutch that can loose it's grab. In other words if it is not working properly, it won't have much resistance when you try to turn it with your hand (while the engine is off)

YNVDIZW124

My 300e aux fan has never turned on but then again it has never gone pass the third bar even if i leave it idling for hours. Also i did the fan clutch mod so my front fan runs faster at idle. I also don't have a fan shroud on my radiator do i need one if my car is running cool?

salehjm

i also replaced the fan clutch sometime ago, it is still basically brand new ... stupid question, is there a tell tale sign when the head gasket goes? my car 112k for miles, but there is a mild click click when running ... let me know.