Radiator cap blowing off with *cold* water?

brought a stunning 1995 328i drove home temp gauge half way then all of a sudden shot up fast, rad cap splilling COLD water all over the floor but temp showing hot engine hot, i suspect thermostat after inspection no thermostat in the car,looking through the paperwork it has had a new radiator, i immediatley checked the oil all is fine drive perfect starts great lots of power but needle allways goes fast to half way mark then after half hour starts spilling out of the rad cap again drivin me crazy now had the car over a week and been unable to appriciate the car at all and thats why i brought a 328 beemer, the garage has no interest in helping me least said the better, after reading up lots and lots should i change the waterpump put a new themostat in then bleed and bleed again, also no hot air from inside heater, i suspect whoever replaced the rad did not follow any of the procedures and it may have more air in it than a baloon lol PLEASE help me !! im going mad with this but i will not give up... txt me if you can 07902 109000



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This post was auto-generated based upon a question asked on our tech article page here: Pelican Technical Article: BMW E30 Coolant Temp Sensor Replacement

[Wayne 962]

Hmm, interesting problem. I would tackle this by replacing my radiator cap to start. Then I would probably replace the thermostat as well. After that, I would bleed, rebleed, and then bleed again. These cars can be difficult to bleed properly, see my article here for complete instructions: http://www.pelicanparts.com/bmw/techarticles/E36-Coolant_Flush/E36-Coolant-Flush.htm

- Wayne

[bostogrun]

I would guess that it's the plastic water impeller issue. Someone probably took the thermostat out as a backyard mechanic fix. My guess would be that waterpump is not circulating coolant so the static coolant in the motor is super-heating the lack of a thermostat allows super high pressure into the expansions tank thus displacing the cooler liquid in the tank and allowing it escape via it's excess pressure release function.


These models have a notorious well documented issue with these pumps flying apart.