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View Full Version : Overheated.. then fine after 1/2 hour



E34N
06-25-2010, 08:47 PM
Basically, I was driving home from work and all of a sudden, the get the chime and the CEL saying "COOLANT TEMP". Quickly pulled into a business driveway out of the road and check it out.

I see some coolant under the car, but don't really see any obvious leaks under the hood. After some time, I notice the coolant is coming from the reservoir overflow hose (at least that what it looks like). I was in a suit and didn't really get into the engine.

I waited a about 30 minutes calling my shop to see if they can send their flat bed. No answer. I was about to call AAA to come and get it, but decided to drive a little down the road out of the driveway I was in (they were closing soon and they didn't have any street parking in front).

Low and behold, I was able to drive all the way to my house without the car overheating, which was only about 2-3 miles. The needle stayed just below 1/2 way.

There were signs prior to the overheating.. no smoke, no idling problems, nothing. I had just exited the freeway, so I was not idling for more than 1 minute.

I've obviously searched and read up on some threads. This one in particular seemed to be similar, although I did not have any smoke issues
http://forums.bimmerforums.com/forum/showthread.php?t=1480529&highlight=overheat

I recently replaced (< 1 month) the reservoir due to a crack, but never had overheating issues prior.

Just changed the oil and didn't see any milky mixture.

Thermostat changed less than 6 months ago.

I'm thinking the pump might be going, but obviously I wanted to check in with you guys to get some suggestions.

m60b30530i
06-25-2010, 08:51 PM
sounds like a bizarre occurrence. My water pump when it died leaked from the bearing. Was yours ever changed ?

It is possible for thermostats to die that quick could of been defective. Or if you didn't bleed the m30 correctly there could have been a air bubble trapped in the system then traveled past the temp sensor triggering the coolant temp message. I would bleed the system out again and double check coolant level.

TGreene
06-25-2010, 09:03 PM
Possibly an air bubble?

ESSSupreme
06-25-2010, 09:27 PM
Your thermostat probably got closed and stuck for a bit causing coolant to shoot back up? Don't know.

Uber 525i
06-25-2010, 09:46 PM
maybe just an air bubble

E34N
06-25-2010, 10:53 PM
Thanks guys. That makes me feel a little better about the incident. I'll bleed the system again. I was thinking it was gonna be much worse. I'll keep you guys posted.

BTW, as a side note, the driveway I happened to pull into was a sand/media blasting business. (Was actually my next stop...) Dropped off the M-systems to get blasted in order to polish the lips and repaint the centers.

SC David
06-25-2010, 11:29 PM
Hope it works out to be something minor. Can't wait to see those refinished M-systems!

upallnight
06-26-2010, 07:47 AM
Your thermostat probably got closed and stuck for a bit causing coolant to shoot back up? Don't know.

+1

Binjammin
06-26-2010, 10:59 AM
If it did overheat you need to change your thermostat. Every time you overheat it cooks the metal in the spring, causing it to need more heat each time to open again. Don't let this be the beginning, spend the $10 and be safe.

E34N
06-26-2010, 11:47 AM
If it did overheat you need to change your thermostat. Every time you overheat it cooks the metal in the spring, causing it to need more heat each time to open again. Don't let this be the beginning, spend the $10 and be safe.

I'll do that and re-bleed the system.

Thanks again guys.

T444E
06-26-2010, 12:29 PM
Quick story.
I brought my 535 in to get it inspected so I could drive it. They do the inspection. The inspector should be the one to drive it out of the bay, for obvious reasons. He comes in and says "uhh you need to drive you car out" I'm like wtf? I get in. The car is dinging like crazy, OBC says COOLANT TEMP. Gauge is PEGGED and now I'm pissed. I back it out and blast the heat, it's July mind you. Park it and shut the engine off but turn the key to on. Let it cool down and drive home with the heat blasting. I let it sit for a few hours and I'm thinking god damnit I just bought the car 2 days ago and the headgasket is gone ffffuuu. Fill the reservoir with coolant, check the oil and it's clean. The car NEVER over heated again and it didn't have any weird symptoms. I was quite surprised and relieved, that M30 can take a beating.

Sidenote, if you need a T-Stat I've got an OEM one sitting here in the box brandy new.

E34N
06-26-2010, 10:26 PM
Ok.. so I finally checked out the car.. and the second I opened the bleed screw, bubbles came out. It looks like that was it. Thanks guys.

I'll keep my eye on it to make sure that was it.

Garrett, I wouldn't mind the tstat. Let me know how much.