I own a 1988 300ce which I love to drive but I do not love what it is doing to my pocket. for a while the car has been overheating. I took the car to a couple of mechanics and so far they haven't fix the problem yet. I have replaced the radiator, the thermostat and the fan clutch (all new). I have noticed a tiny leak on the auxiliary water pump which only happens when the car overheats. the car overheats only when it's idling in heavy traffic and the auxiliary fan will only kick in at high speed and it is loud that I can hear it inside the car.once traffic starts to move it runs fine. the temperature will drop to normal and the car runs fine. perhaps someone can give me some advise on what could be the problem. Also, my ac only blows hot air, I wonder if it is because of the overheating problem
Please help ~R~[:(]
first of all, welcome [:)]
secondly, who's told you your car is overheating?
this ...
first of all, welcome [:)]
secondly, who's told you your car is overheating?
this is roughly how all MB's work.
Cold engine - ie below 82c the thermostat is closed
warm engine - 87c thermostat open but auxilliary fan not working
hot engine - 105c the auxilliary fan kicks in and cools the engine to approx 90c.
This is not overheating - it's normal and I agree it's a little disconcerting at first but you soon get used to it happening and pay little regard of the temp guage until it hits the red line (hopefully never).
The marks on your temp guage are at 80c, 100c and 120c running with water/coolant mix in a pressuried system is no problem at 105c-110c.
If your A/c is blowing hot air only it may just need re gassing but get it checked over first.
Local mechanics seldom "understand" Mercs, take your car to a specialist and let them diagnose any problems you may have. Trust me it will save you money in the long run.
MY MECHANIC THOUGHT IT WAS UNUSUAL FOR THE TEMP TO ALMOST HIT REDLINE ONCE THE CAR WAS TURNED OFF AFTER BEING RUNNING FOR SOME TIME. THE REASON WE KNOW THAT IS BECAUSE WHEN I WOULD TURN THE KEY TO IGNITION THE TEMP WILL SHOW VERY HIGH AND THE AUX. FAN WILL KICK IN TO BRING THE TEMP DOWN TO NORMAL BUT IT TAKES A WHILE FOR THE FAN TO BRING THE TEMP DOWN. BUT IF I TURN THE CAR ON THE TEMP WILL GO DOWN FASTER THAN IF I JUST HAD IT ON IGNITION. IS THERE A WAY TO CHECK IF THE AUX. FAN IS WORKING? OR PERHAPS THE MONOVALVE COULD BE THE PROB. JUST GUESSING.
ANY HELP WILL DO.
THANKS FOR REPLYING.
[:)]
Of course the engine temp will drop quicker whilst the engine is running - the water pump ...
Of course the engine temp will drop quicker whilst the engine is running - the water pump is circulating the coolant. If the engine is switched off and the fans are on all they are doing is cooling the water in the radiator so they will have little effect on the temperature guage.
Why does the temp guage rise when the car is first switched on? If the engine is hot, then it's basic physics - the hot coolant will rise to the top of the system thus giving a false reading of the overall temperature, add to that heat transferrance from the engine casing to the sender - you can only rely on that guage whilst the engine is running.
My really honest opinion is that you get your mechanic to admit he hasn't got a clue how these cars work and either accept that the behaviour of your car is far from unusual or take it to a Mercedes specialist who can accurately diagnose any problem you may or may not have.
there's a very quick, albeit primitive way of checking your fan - with a carrot [:)]
1, start the engine from cold and push the carrot tip into the fan - the fan blades should stop turning.
2, once the engine temperature has risen to approx 105c try the carrot again - this time the fan should slice the tip off the carrot.
3, after the fan has bee running for a few minutes and the engine temp has dropped again use the carrot again - the blades should stop spinning.
Whatever you do...........
DO NOT PUT YOUR FINGERS IN THE FAN BLADES WHILST THE ENGINE IS RUNNING OR THE BLADES ARE TURNING.
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