E30 Zone

Hi Guys,

I bought a 1991 730i SE which is to be used to do a 1500 mile roadtrip through Europe to raise money for UNICEF, the children's charity. The car's been SORN for the last 5 years so needs a bit of work.

I've given it a full service, oil, filters, plugs, etc. but it seems to rev up and down between 1200-1700 rpm on idle. It's smooth through the complete rev range and drives perfectly. I've taken the idle control valve off and given it a good clean but it hasn't resolved it. Any ideas what else it could be?

Also, there were a lot of airlocks in the rad and I have bled the system out, filled it with water and let the engine run for some time. It didn't seem to overheat when run for 30mins or so. However, I took it for a short drive yesterday and the temp needle almost hit red. No obvious leaks, any ideas what it could be?

They all sound like common M30 problems but I'm not too familiar with these at all.

Cheers
Ruhul

is your viscous locking mate?

Havn't checked TBH
The fan was kicking in and pressure was building up, it all seemed fine when the car was stationary and engine was running. It's only when i took it for a drive a couple of days later, temp seems to creep up very quickly.

possibilities are-

thermostat knackered
water pump
viscous
headgasket
airlock

needs to be a process of elimination mate

as above, check the viscous (do the newspaper test), also check the thermostat, you said you have bled the system, have you turned the heaters on and are you getting constant hot air out of them or are they blowing hot/cold, if so then you have an airlock and havent bled the system correctly, but i would advise replacing the viscous coupling anyway as they arent expensive! and as blingsta said it is a process of elimination, also check underneath your oil filler cap for any mayo like gunk, as this means the water and oil is mixing and generally means the headgasket has failed

no white gunk in the engine, water pump was replaced few thousand miles ago, heaters not working at all at the moment (was a blown fuse, replaced it but still didn't work), will have another look at heater. Pretty sure I bled out the aorlocks. So all it reallt leaves is the viscous and thermostat. Should be an easy fix. I hope!