1990 300 sel overheating/radio code

It probably is bad fan clutch that cause the overheating... and yes, the aux fan in front of radiator/condenser should have come on whenever AC is on or car reaches 95 degree C. For this aux fan, check fuse... take it out and inspect it. I would suspect the thermoswitches are bad.

It is best you let MB tech look over the car for you. The old timers... who really knows about these cars.

How about a new thermostat, cheapest fix and right in front. Sounds like its not giving any time for water to cool. Might replace the coolant with proper mixture. Of course the water pump could be supspect, normally makes noise first. Charge the A/C system. That fan won't come on and comprssor wont run if its not. If it is charged you have a bad pressure switch and need to bleed the a/c to change it then refill. You can jumper the switch to make sure the fan works first tho, sometimes the fans lock up. Also check all the fuse (suggest ne replacement) gets rid of gremlins.

Thanks... changed the thermostat, still running a little hot. What is the correct coolant ratio

"macdrone" wrote

Replace the upper radiator hose-you can get a better part than the MB original at Adv. Auto Parts, (theirs is reinforced with wire mesh) for $6.00-I had one collapse in a 1991 300 SE with 220k miles on it which caused the engine temp to soar until I could get the car off the road.

if the fan never runs you need to check the fuses and then unplug the fan run some wires straight from the battery to the fan make sure its not sized or dead (happens sometimes). Also there should be a relay, I'll look at my Cd's and see if I can find it for you.

hi macdrone... is it the auxillary fan switch that I should unplug??? Thanks...

"macdrone" wrote

forgot to add...it is just the fan on the left (if you are facing the front of the car) that is not functioning...

"kostecky6" wrote