Coolant Boiling

Wed Mar 04, 2009 8:48 pm

Hey guys and gals,

Im new to E30 ownership, 325i sport. Quick question, the car is running ok and is not losing any water and no mayonaise and the temp gauge never moves off centre even when driving hard. Once stopped, along with the viscous fan the temp goes up and the coolant boils off but never during driving or idle? any Ideas??

cheers

please dont tell me i bought a pig in a poke.

Wed Mar 04, 2009 9:02 pm

What do you mean by "once stopped"? The engine, or forward movement of the car with the engine idling?

Wed Mar 04, 2009 9:10 pm

After i switch the engine off the water boils when drivin hard so not every time.

Wed Mar 04, 2009 9:32 pm

When you stop the engine, the coolant temperature in places will be above 100 Celsius, which is why the cooling system runs at 1.4 bar.
Check out/replace your coolant bottle pressure cap. There was a safety recall regarding this cap in 1996, and if yours hasn't been changed, your dealer should give you a nice new one. (Give them the VIN.)

Wed Mar 04, 2009 9:49 pm

COULD IT B AN AIRLOCK IN THE SYSTEM? tHE WATER BOILS IN THE HEADER AND COMES OUT THE OVERFLOW?

Wed Mar 04, 2009 9:53 pm

I'M NOT DEAF!!!
If the water boils it will probably drive out any airlock anyway. Does the heater work?

Wed Mar 04, 2009 10:03 pm

Yeah soz about that didnt realise caps was on till after posted. LOL. Yeah heater works fine. Hopefully not head? just seems weird.

Wed Mar 04, 2009 10:10 pm

If the heater works, there's unlikely to be an airlock.

Wed Mar 04, 2009 10:29 pm

Ill try replacing the cap hopefully that will sort it?

Wed Mar 04, 2009 10:47 pm

COULD IT B AN AIRLOCK IN THE SYSTEM? tHE WATER BOILS IN THE HEADER AND COMES OUT THE OVERFLOW?

Pardon?

Wed Mar 04, 2009 11:23 pm

Also if you have little or no coolant in the system the boiling temp will be very low.

Thu Mar 05, 2009 4:58 pm

+1 for the cap on the expansion tank - mine did this briefly, although I had the correct cap, so I replaced it anyway, along with the expansion tank itself. If the seal goes then you'll hear it boiling up after you switch the engine off.

Sat Mar 07, 2009 6:07 pm

Fixed that one, now water is coming out tiny hole in pipe from the thermostat housing to water pump. But looks down to worn engine mounts causing engine to move a little, allowing fan to catch pipe. But cheap easy fix according to haynes. Just time required.

cheers