E30 Zone

Hi My 318i temp guage sits on the top edge of the blue all the time. I have also noticed that the heater never really blows hot air even on full,. Could this be a head gasket problem?

Cheers

What's the water level in the header tank???
Does the needle move at all??
Have you tried to bleed the system or bled and refilled it????

Sounds like an air lock or blockage.
Get the car up to temp and check the bottom hose from the red to the engine block, car switched off!!
Also your stat could be open permanently, faulty.

Hi yes the needle does move from the bottom of the blue to the top. I checked the waterlevel before starting the car this am and it took less than 1/4 of a pint to bring it to the cold mark. Done approx 60 miles since and level has not dropped at all. Again I checked when the car was cold.

How do I bleed the system? Where is the stat located and is it easily replaced?

Thanks for the help.

Theres a Bleed screw on the top of the thermostat housing which is located at the front of the engine.
Loosen it, and let any air out through there.

Be careful with the bleed screw as they are well known for busting off - soak it with WD40 for a couple of days before attempting to undo it.

Also make sure the heater is on hot and ideally raise the front of the car up to aid with any air locks making their way out of the system.

M40 engines may also have a bleed screw built into the Rad I think

This sounds like the thermostat has stuck open, my 318is had exactly the same problem, easy to replace and now it sits exactly half-way on the temp gauge.

Which engine do you have? M10 or M40? if you're not sure then the M10 was in the chrome bumpered E30s and the M40 in the plastic bumper cars as a general rule.
My I.S has a slightly different set-up but I'm sure if its an M40 then it'll be in the same place i.e on the end of the head above the water pump, if its the M10 then it has an in-line canister thermostat. As well as the usual steps when bleeding it make sure the heater control is on hot and the ignition is on so that the heater valve can open, having the front raised higher than the rear will help and make sure you bleed the system properly-do a search on here as there are plenty of posts on the subject

Genuine BMW thermostats are notorious for breaking one arm of the bridge that supports the centre part (the capsule and the valve disc). When this happens the disc tends to sit in its seat off centre, allowing plenty of coolant past even when it's closed.
Sounds like yours might be in this condition.

Many thanks people for all the info. There does not seem to be any air in the system so I will change the stat at the weekend and let you know how I get on.