[Jazzbass]

Posting this from the side of the road as I limp home in my E90 330i. I can drive about 1/4 mile at a time and then the overheat light comes on and I pull over and wait for it to cool down enough to drive another 1/4 mile. There is coolant underneath the coolant reservoir. Any guesses? Water pump is my thought. We'll see when (if) I get home.

On the plus side, waiting for the car to cool down has given me time to read the internet and learn how to get in to the double secret BMW menus. So I can actually see my coolant temp now, which is nice.

[VaSteve]

Originally Posted by Jazzbass

There is coolant underneath the coolant reservoir. Any guesses? Water pump is my thought.

Water pump is behind the fan. Guessing that maybe the reservoir cracked?

[APKhaos]

Jazz,
Where are you, and how far from home? I can bring my trailer and load you up in a snap. Better than covering miles a quarter of a mile at a time and less risk of collateral damage. Call me!
Coolant leak may well be overflow from the coolant reservoir. If its overheating within a few minutes, chances are its a water pump. Simple enough to replace.

[Jazzbass]

Originally Posted by VaSteve

Water pump is behind the fan. Guessing that maybe the reservoir cracked?

Pretty sure it's not. E90s have an electric pump that is under the car on the passenger side by the steering rack. This is approx where I saw the coolant, btw. Not 100% sure this is the problem, but its the leading guess right now.

[Jazzbass]

Originally Posted by APKhaos

Jazz,
Where are you, and how far from home? I can bring my trailer and load you up in a snap. Better than covering miles a quarter of a mile at a time and less risk of collateral damage. Call me!
Coolant leak may well be overflow from the coolant reservoir. If its overheating within a few minutes, changes are its a water pump. Simple enough to replace.

I'm home now, but I really appreciate the offer. The car was only a couple miles from home when the problem started, and once I found out how to display the coolant temp I could monitor things close enough to drive, stop, post on Dorki while it cooled down, the drive some more.

Thank god for the 60 degree weather tomorrow - I'll get the car on the lift and check things out. The more I read on e90post, the more I think water pump.

[APKhaos]

Sorry I didn't see your post earlier.
Unless you have dumped a significant volume of coolant [which could be a cracked reservoir or a hose] its more than likely the pump. BMWs are famous for their flimsy cooling system designs.
http://getbmwparts.com/ is the online side of BMW Silver Spring. Decent onlineish pricing, and will probably have a pump in stock.

[VaSteve]

Electric pump? What the hell for?

[Jazzbass]

Originally Posted by VaSteve

Electric pump? What the hell for?

One more thing to break. BMW engineers were worried that there weren't enough failure points on their cooling systems already.

[Lupin..the..3rd]

The E90 water pump is electric?? Weird. Sux to hear the roadside troubles. I've got a new E46 pump and thermostat here for planned cooling system overhaul. I think E36 uses the same part, but it sounds like E90 is way different. The plastic impeller breaks apart on the E36/E46 and causes the same symptoms you've described. Stupid BMW cooling system.

[Trak Ratt]

Wow, the more I hear about BMWs (all above) the less I want one. OK, ok I prolly haven't wanted one since the 2002 Tii and Bravaria