Heater not working

[Rasta]

I have seen posts about this topic but I cannot seem to fix my problem. I am trying to fix the heater on my '91 318is. The heater has not work since I had to do a cooling system repair about 10 years ago. Long story short, the car overheated and burnt head gasket. I fixed it but never installed a thermostat in it. A couple of years after that repair, the heater thermostat, the one by the break pump, broke the top seal and was leaking so I eliminated it. Since then the heater has not worked. I am doing miscelaneous work to the car right now and I installed the front thermostat and also bought a new heater thermostat and installed it. I filled the system with water/coolant and bled it but the heater still doesn't work. The temperature gauge does not rise over a little less than half. Hoses that go to the heater core do not warm up. The system blows cold air. The blower works on all speeds. Can anybody share some wisdom?

[bmwm42]

are you sure you dont have the hoses backwards.

[Carib]

It usually takes several bleeding attempts to get all the air out of the system. Try a couple more times. I had to bleed my system about 5 times before I got all the air out. Once done, I got heat.

Another possibility is that the thermostat you got opens at a lower temp. Which thermostat did you get?

[Rasta]

Acording to some online pictures and the realoem blow out pictures I installed the hoses correctly. The top hose connected to the heater core has the T and it connects to the heater thermostat.

I am not sure what thermostat I got. I purchased it when I did the first repair but never installed it. The heater thermostat I got the oem. I will keep trying bleeding the system.

What is the best way to bleed the system? when you add more fluid to the expansion tank does this add more air to the system?

[Chuck C]

It seems like you still have the cooling system recall parts installed. This recall put a thermostat in the heater supply hose that would cut off water flow to the heater in the case of engine overheating, to prevent the heater core from blowing out and dumping hot water on the driver's feet and legs. The tee fitting routed the water back to the engine, through the small hose. It's not unheard of for the added-on t-stat to stick closed, especially if the engine has ever been overheated--like yours. Buy two new heater hoses--inlet and outlet--and don't cut them to reinstall either the tee fitting or the 'heater thermostat.' Get that s**t out of there, and watch your temp gauge. Of course, your heater core might blow, if it really has been 10 years since it had hot water in it.

[Rasta]

The heater thermostat is brand new. I would like to keep it installed. I was planning to disconnect the hoses from the heater core and run water through it and see what happens. At this point I don't know if there is an air pocket inside of it. Any other ideas?

[e30s50dan]

When you are bleeding the system..make sure the heater is turned on high and fan on high,this will open the valve!