I'm having a complicated "overheating" problem with my '97 BMW 528i...?

phillyman2633

New member
What else is new, right? This car has been giving me so many problems lately, it runs and looks great but everything around the engine seems to be falling apart.

OK, so here's my problem: I'm having my temp. gage run all the way up into the red and stay there for extended periods of time. However, the car isn't actually overheating, because I've been driving like this for 3 weeks and there's no symptoms of actually overheating i.e. engine roughness or coolant boiling over. Also, I had this verified using a laser thermometer. It's definitely not the radiator, which tested fine for flow.

Recently (within 4000 miles) replaced: Engine-driven fan and fan clutch, thermostat, electric aux. fan.

Another peculiar thing, my heat doesn't blow hot continuously. The temp. gage will be up in the red and the heat will be blowing straight outside air, then the gage needle will go down to normal running temp. and the heat will blow hot for a minute, then it will go back up into the red and the heat will blow cold again.

I've been to 3 different places in a month but can't take it to a BMW place because I don't have the money! Any help with this issue would be greatly appreciated and thanks for taking the time to read such a lengthy description.
 

bobweb

Member
It sounds like you may have some air trapped in your cooling system that needs to be bled out. When the air bubble moves past the dash temperature gauge sensor, you get incorrect readings. You could replace the temperature gauge sensor and make sure the wiring makes a good connection at the sensor. An air bubble would also account for the heater heat variations.
The two answers above me are right on!! Check that coolant level too!
 
HI
sounds like you low on coolant.... with low coolant the water pump cannot move enough coolant to supple hot coolant to the heating system. Check it at the radiator its self... with the motor cold pull the radiator cap off the fluid should be all the way to the top or no more than 1" below the top.
good luck
tim
 
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