E36 318is Coupe (m42 Engine)

[munky999]

When I bought my 3-series in January, the sales man told me that he had just changed the thermostat and that he thought some air was still trapped in the heater matrix. The Result? when the engine is at idle the heater blows cold air into the cabin and when the revs are above idle we have warm air again. Especially annoying in winter!
I have recently had to change the coolant as the bleed valve cracked and leaked coolant. After aquiring a new bleed valve I set about re-filling the coolant system to exacting instructions from my Haynes Manual. The result you may ask? exactly the same as before!!!!!!!!!!!!!!!!!!!!!!!!

Why is this happening? It is truly annoying! People have said to me that it could be the result of a faulty water pump but I doubt this as my car has never over-heated since buying it.

Does anyone have any handy hints and tips about good ways to the bleed the coolant system correctly?

And does anyone know why the M42 engine doesn't have a bleed valve on the thermostat housing as all other four cylinder engines in the range do? ghead

[bad man working]

I think the diagnosis is spot on it's air locked the way to bleed it: from cold or make sure there's no presure in the system remove the rad cap and take the bleed screw right out tip coolant (50%mix) into the rad until it runs out of the the bleed hole, keep fill until no more air comes out. catch the bleed screw by a couple of threads with the rad cap still of start the engine coolant should run out off the loose bleed screw and the ecoolant level will drop any remaining air will be expelled through the bleed screw. when the level gets to the mark tighten the the screw (don't over do it they snap easy) you should now have a strong jet of collant coming into the rad just below the rad cap seat. it don't need the screw in the stat they normaly bleed OK to check it's bleed and or the water pumps OK check for this jet into the rad pick the revs up a bit if your not sure. if you have the problem check the stat yourself maybe he took it out.

[Black318IS]

Have you checked the dial above the stereo? because i had that smae problem until i relized that the dial was on cold and not hot even though i had the temperature all the way up, it still blew out cold air. I know it sounds stupid, but it could be it

[Autotechnica]

Bleed valve for the coolant should be on the block under the car.