Vert overheating... Ideas

[bowtie2bimmer]

So this morning while commuting into work I hit unusually bad traffic. After about 30 min, I see white stuff billowing from my hood. My Temp gauge is pushed all the way to the red. I pull off and let her cool down.

The temp gauge cools till about the midway mark, i try to drive her but in less than a mile she is hot again.

This time I let her cool down till she is in the blue. I try once more and she heats up in about 1/4 mile.

I decided to take her home. While driving back the gauge would go between the "3/4" mark to red, never really cooling back to the mid point. Its a 50mph ride home with not alot of stops so there was plenty of air moving...

Thoughts?

[F34R]

Check oil for a milky color
Check coolant level in the reservoir
Check for leaks

[bowtie2bimmer]

Already checked the oil, no water

The res still has coolant, but its still hot so don't want to open it as of yet.

No visible leaks

I'm thinking Thermo maybe?

[F34R]

You have the stock mechanical fan? and have you bleed the air from the system lately?

[bowtie2bimmer]

stock fan and no. Did the water pump back in march

[Victor_PR]

Once cooled down, you should check the upper radiator hose. Just squeeze it to see if you have a leak (could be very small). This happened to me once and the cause was that the fan clutch was slowly shaving the hose.

If hose good, then like you said, it could be a stuck thermostat.

[stamar]

I would bet you have a leeak, and now you also have an air bubble.

Try and bleed the system from the overflow hose on the radiatoor not the air bleed screw as the bleed screw is below the top radiator hose and always leaves air in the system.

millions of bmw owners are always confused by this.

for what it matters is the coolant light on?

[bowtie2bimmer]

After I overheated the first time, i went to open the cap and heard the system depressurize and saw the coolant rise. Could that have caused an air bubble

[stamar]

when you took ff thee cap was the coolant level there?

first off this thermostat always fails open. Almost no e30s get a stuck closed thermostat.

If yoou dont have a leak, and you overheated while idling that does sound like that fan. Is your fan turning on when hot?

Ok well then you can get a leak only under pressure or an annoying one is in the throttle body thing that only leaks at freeway.

once you have a leak you have air in the system.....

ok next fill er up with water, pinch the top radiator hose hard as you can, turn it on does it force your fingers apart? If yes good if no water pump.

that should be all, leak fan pump you should see in a minute.

I bet its a leak. slow, causes an air bubble.

sign of an air bubble is the heater blows cold air.

[jlevie]

After I overheated the first time, i went to open the cap and heard the system depressurize and saw the coolant rise. Could that have caused an air bubble

If you did this when the engine had cooled off, it means that there is air in the system. Given the history, I suspect that the first overhead was caused by a bad fan clutch. An overheat bad enough to vent coolant is one that is bad enough to damage the head gasket, which explains the air in to cooling system and the subsequent overheats.

[bowtie2bimmer]

well it wasn't cool.. more like at operating temp... just not in the red

[bowtie2bimmer]

So its been about 2 hours. Its fully cooled down. I pulle doff the cap, de pressurized and the res is empty (expected that with all the steam). I topped it off and fired the car up. It is running now.

Question, does the fan run constantly or only once it gets to temp?

[bowtie2bimmer]

got to temp, fans not working...

What to check?

[noid]

http://www.rtsauto.com/diagnosing-and-fixing-cooling-system-and-overheating-issues/

[bowtie2bimmer]

ok, so the clutch fan was not spinning.... I got a new one... still not spinning...

????????????? Need help asap