BMW 328i problem!!! Overheating!!!

[rude_lude911]

guyz im in need of desperate help. I got a 97' BMW 328i 5spd and its OVERHEATING!!! I mean i thought it was the thermostat that needed replacing. So i replaced the thermostat and filled it with antifreeze and thought that would do the trick. Apparently yea for 5 minutes and whatta ya kno OVERHEATING!!! again. I dont have a blown head gasket cuz no white smoke or anything coming from the exhaust. Im thinking water pump but im not sure. Guys help me out here. Any BMW techs, anyone with Bimmer knowledge. please!!!

[Elbow]

Can still be the headgasket.

Is coolant flowing? Check that.

Any noise or leaking from the waterpump?

Check the oil and coolant, any milky colors or anything?

Check the spark plugs, sometimes you can tell if your HG is leaking if a plug looks steam cleaned.

Flush the radiator.

[revhard05]

On Most Bmws there is a sensor that goes in the radiator, (i beleve) that lets the Aux. fan know when to kick on. I have known a few of these guys to go out pretty common problem after 10 yrs of service. This is only the case when sitting still. When moving and it over heats it could be a handfull of things, From stopped up catalytic converter (burning excess oil can cause this which in turn cane cause the head gasket to blow)) to just needing to flush the radiator. I would flush the radiator anyways. IT also could be vapor locked from running it low on coolant. to check if vapor locked, pump the top hose to see if it has air or water in it. (air=compressable, water=non compressible)

[rude_lude911]

it mean it could be a blown head gasket but i havent the slightest clue. I mean new thermostat and water pump is turning but still keeps building up pressure and blowin' out antifreeze.

[Elbow]

It's blowing it out? From where?

[boostleak]

it mean it could be a blown head gasket but i havent the slightest clue. I mean new thermostat and water pump is turning but still keeps building up pressure and blowin' out antifreeze.

if its building pressure through the radiator, and expelling through the cap. It might be something as simple as the cap not being to hold pressure anymore, that happen to me. Its a cheap and easy fix. That happen to my 85 maxima. Another problem could just be all the pressure in the radiator. so you have to release it. (by slowly opening the radiator cap, you probably will get burned) It happen to my 240 after heavy driving. So what my buddy and i did was open the cap, release all the pressure but do it slowly. Drove it w/out the radiator cap, with heat on high blast to the nearest gas station and refilled it. Never had a problem since.

[OnURleft]

The radiator on all E36's should be done at the absolute MAX every 90,000 miles if you plan on doing any type of spirited driving. It sounds annoying but these radiators can be bought at cost for barely more than a bill. The water pump and thermostat should be done ever 30k. Make sure you get the right temp thermostat switch and if you do this preventative maintenance and you should never have problems like you have now