Colling System Enigma - HELP!

[rfc2307]

Good Morning, a question please. I am having very puzzeling cooling problems. Last Friday I topped off the overflow tank on my 1997 ///M3 with BMW anti-freeze. As I got off the off ramp to the workplace the car was steaming from under the hood. As I pulled into the parking lot the upper radiator hose blew off the radiator. No problems for the past four years, at all. I had recently replaced the water pump, aux fan switch, thermostat, both hoses, both belts and the water pump pulley. No overheating noted until last friday.

Saturday, I installed a NEW water pump, thermostat. The flushed the system twice, and filled with distilled water, two bottles of Red Line water wetter, and topped it off with BMW anti-freeze.

Drove two miles, red line hot. Pulled over, let it cool down, massaged hoses, bled system. Drove two miles, boil over.

Gave up and called tow truck.

What do you think? I must admit I have recently noticed what looks like vapor in the exhaust, exhaust is usually visible on COLD mornings, but recently (last three weeks) I have noticed visible exhaust at all times.

I am afraid it is the head gasket. Any ideas what this MIGHT cost?

Please reply to: rmthomas@adnc.com

Thanks

[ptg95m3]

I don't know, but after the race on Sunday, my temp shoots up if the car is sitting still or moving slowly - fine at speed.

I go into the shop tomorrow and I'll ask what could cause your symptons.

Oh, here's a write up of the race weekend with pics and video from another car on track:

California Speedway race weekend

[Jared at Pelican Parts]

Sounds like a hydrolocked cooling system

Sometimes, when you fill a system, no matter how much you bleed it, it still has air in the system. Did you make sure that you completely bled the system? Maybe try opening the bleed screw while the engine is running, then rev the motor up to increase the water pressure. This will force any remaining air out of the system. Just be sure to keep filling it with coolant as you are doing this..

[ptg95m3]

Mine turned out to be a broken plastic return tube in the overflow tank. Apparently a notorious problem with this overflow tank design. I wonder if anyone has ever made an aftermarket model with an aluminum tube?