318i M40 Engine Overheating HELP PLEASE!

[j555boy]

Hi,

I have brought an L reg 318i (used to be a 316i but converted to a 318i) touring and it has developed a overheating/pressurising problem.

No oil or water mix (no mayo), its not using water, but when it nearly overheats near the red i turn off the engine and hear the engine bubbling. The radiator pipes are rock hard and when i realease the radiator cap water air comes out first then water.

When i brought it a couple of weeks ago the last owner said it has a leaky radiator but i have not seen it leaking once.

I know these suffer from dodgy thermostats, should i change that? Blocked radiator? Water pump? Air lock?

Or cracked head or gasket?

Hot air is still pumping through the heater into the car.

Using quite abit of petrol also.

Also, the rad fan is connected to be prementely on with a switch to turn it off inside the car, I just have it on all the time to be on the safe side.

Which direction should i go first? Headgasket test?

If its the head or gasket do i need to get the head skimmed and pressure tested? Do these heads crack easily like 325i heads?

Thanks Jamie

[318ichris]

if it is the head witch has gone then you will most likley need to get it skimmed

[j555boy]

Brianmoooore? Advice required! Thanks

[E30k]

had this once it was a blocked and leaking rad but the problem would only happen when the car hard been driven hard or in traffic

[no2lurch]

The fan will always spin- the faster the engine speed, the faster the fan speed- thats normal.

Have you tried opening the bleed screw on the rad with the engine running before it gets into the red?

The water pump could be shot- mine chewed it's impellor off.

[Kos]

have you tried bleeding it?

when its cold where's the water level ?

if the rad had leak, then change it

[Brianmoooore]

If you take the pressure cap off when the car is overheating (or even at normal working temperature) then it will push water out. The normal operating temperature is close to boiling point at atmospheric pressure, and the coolant will exceed 100 degrees in parts of the head. The system is pressurised to raise the boiling point.
You say you leave the rad fan turned on permanently? E30's don't have an electric fan unless they have aircon, or has this car been 'modified'? Is there a fan attached to the front of the water pump pulley, and plastic ducting to it from the back of the radiator?
If the heater works properly, I doubt if you have an airlock or anything seriously wrong with the water pump.
How certain are you that the car does overheat? Just by the gauge? If so, check that the small brass nut on the instrument cluster, directly behind the temp. gauge, is tight or even present.
Check that the radiator pressure cap has been changed under the 1996 safety recall.

[j555boy]

Put in a new thermostat and radiator today and bleed the system.

Going out in a minute to see how it goes!

Thanks for advice.

Will let you know how it goes.

[j555boy]

All sorted, think it was a blocked radiator.

Thanks!