julien_saadeh
Hello LebGeeks,
I have a Mercedes SE-320 1992 that is running hot going uphill, especially in slow traffic.
The engine's temperature would increase from 80C to 110C in a 5 minute slow trip uphill.
It would stop heating when I get on a flat surface, and after a while, the temperature would slowly drop.
Going downhill would cool the engine quickly from 100C to 90C in 30 seconds.
Other information:
Engine fans start spinning at 80C.
120C is the maximum temperature allowed (on the dashboard).
There is no coolant leak, and I'm only using water. No antifreeze.
The car usually ran at 80-100C (absolute maximum) during long trips, or even during traffic jams.
Engine fans are relatively loud compared to other cars of this model. Everybody would know that I'm here when I get there :P
I rarely post here, but I value the efforts of this community and I hope this thread will be informative for other people too.
Thank you.
MAS
Hey,
well it seems you've done good job debugging the issue, what i suggest is:
-check if the fans are always spinning at 80C (if the maximum is 100C i think the fans should start before 80C), if so then there's no problem with the heat sensor.
-if the maximum of the car is 100C and ure reaching this temprature in normal trips, the problem may be in the water pump(but we can rule that out since the temperature is cooling down after that).
-you can check the radiator and get it cleaned, its gonna be full of calcaire because you're using only water in it.
Hope this will help.
julien_saadeh
Hello,
The car's engine was replaced few months ago, along with the radiator and water pump. But you said something very important. Once, the fans didn't start (they are loud enough for you to realize), that day the temperature was increasing very quickly. I had to pull over. The car does have some electrical issues btw, and now you made me think again about it (what if the fans are no longer (or intermittently) spinning when driving?).
I think I'm left with 2 options: bad electrical connections and bad airflow (from the fan noise). It's logical, when you drive uphill (especially slowly), you have a high rpm and no airflow, but while downhill, you have a low rpm and enough airflow. Unless there is some other secret...
Thanks
Draguen
Well, on my car (Alfa Romeo) it does more or less the same thing, whenever the car is going downhill, the engine heats up.
after a few weeks i've discovered that it a design flaw from the car: if the car's cooling system is not full, the water doesn't flow well, or something like that anyway.
So in other words, for the car to stop overheating when going downhill, i just have to make sure that the car's radiator is full (not half empty).
julien_saadeh
I got the car fixed last week. It had a clogged radiator and a bad clutch for the internal fan. The mechanic mixed antifreeze with water 50-50%. Now the temp. doesn't go beyond 85C anymore and the car runs below 80C most of the time, which is perfect.