1987 E30 no heat? Help UPDATE

[E30-Ellerman]

So have been trying to figure out why I have no heat for quite some time, hard to diagnose when it went bad as I've only driven the car 3 times since September.

Took it in to get a coolant flush done, may have been after that, that was done in Octoberish, have only driven it once after that and had no heat so probably it.

What I've done:

Was going to do a heater core flush - bought everything to do it however, took the heater core outlet hose off to replace it and the coolant that came out of the heater core was clean and bright leading me to believe the heater core wasn't plugged and in good shape.

Filled up expansion tank to replace the coolant I had lost when replacing the hose, let it get hot, unscrewed the tstat screw until coolant started to dribble out, tightened back up.

Still no heat, checked every hose including heater core hoses - every hose was very hot except for the hose coming off the thermostat on the driver side going down to the bottom of the radiator. Figure this may have something to do with it, any ideas? Sounds like the thermostat is sticking closed so no coolant is getting to the rad on the driver side however, it stayed at normal operating temperature idling for about 3-5 minutes and didn't move from the middle of the temp gauge.

Thank you

[325isman]

No heat

It seems that when they did the flush air entered the system which will cause it to blow cold air. There is a screw on top of the thermostat housing, run your car and open that screw up let off pressure and close it back down. It's like bleeding brakes where you get air out of system. Try this it worked for me.

[R1dd1ck913]

Have you check the heater control valve on the inside of the car?

[R1dd1ck913]

Number 16 on this page http://www.realoem.com/bmw/enUS/show...diagId=64_0514

[E30-Ellerman]

It seems that when they did the flush air entered the system which will cause it to blow cold air. There is a screw on top of the thermostat housing, run your car and open that screw up let off pressure and close it back down. It's like bleeding brakes where you get air out of system. Try this it worked for me.

Yes I thought that as well, and did this.. no air pressure came out, coolant dribbled out but that's it... didn't fix anything

[E30-Ellerman]

Have you check the heater control valve on the inside of the car?

I have not, thinking that will be my next check when I get some time off... How would I know if it's gone bad?

Part of me is thinking there's an issue with the thermostat (causing no coolant to go to the driver side rad hose) and possibly the heater control valve... Doesn't overheat though.

[Das Delfin]

When you bled your system did you have the heater on full blast? Also on some cars there was a recall to install a second heater control along the hose going to the heater core in the engine compartment. could be that too. Check if the hose is hot before and after this extra valve, if you have it

[E30-Ellerman]

Cool, will check that out Das Delfin - it's a Canadian car, not sure if that changes anything... And yes when we bled the cooling system, heat was on full.

[E30-Ellerman]

Ok update today.

Changed the thermostat, bled the system, still no heat. The car actually ran cooler than before and never got up to operating temperature. Thought of it after the fact, but I installed the thermostat on about a 45 degree angle as opposed to 'up and down' - would that affect anything?

Took apart the console to check the heater control valve and heater core.. Both pipes coming to and from the heater control valve are both hot and the heater core itself is hot.

So... as for the heat issue, thinking maybe it's a cable at the heat actuator that came loose and its stuck on cold, I just don't know how to get to those actuators.

Any input would be awesome, console is taken apart still, dash and heater area is still in tact.

Thanks!

[E30-Ellerman]

Apologize, know people are probably getting sick of this but I can't figure it out.

Had a buddy whose real knowledgeable with e30's look at it too and can't see anything obvious.

Today had the HVAC controls out, PO made a birds nest disaster of wires but nothing was obviously disconnected. The recirculation vents worked as they should, heater knob was opening and closing properly and connected.

Possibly maybe the electrical connection on the heater control valve is shot and not telling the valve to open? I don't know how it works..
__________________

[spdracrm3]

if heater core is getting hot then its not a coolant flow problem (btw the electric portion on the heater control valve is only used to shut off flow for maximum AC )

so if heater core is hot, is the fan working to blow air across the core into cabin? if fan is working there should to be heat coming out somewhere thru either the defrost ,vents or floor registers (make sure the cables and doors are moving). does your car have AC ? if not does it have a cabin filter? (euro/canadian cars came with them on cars with no AC) filter may be plugged causing no airflow (filter comes out right side of HVAC box behind glovebox)

also lower hose on radiator wont get hot as this is the cooled coolant returning to engine after flowing thru the radiator

[E30-Ellerman]

Heater core is getting hot so not a flow problem, fan works on all 4 settings but blows the same constant temperature of air no matter what the heater control is set to.. My car has A/C that has been removed and is a Canadian car.

I'll check to see if there is a cabin air filter, HVAC is still pulled apart.

And thanks for the lower hose info - replaced the thermostat anyways, didn't fix anything though.

[argon]

not trying to steal the thread but on a related topic can anyone confirm which is the inlet and outlet of the heater pipes on the e30 firewall? is there an orientation that i need to follow or the direction of the fluid doesn't matter? thanks

[spdracrm3]

so if you let the core get hot fan off and then turn the fan on full speed is it hot and then cools rapidly (does core or one of the hoses coming out of core get cold with fan on full ?). just wondering if the flow is restricted , in US they had a recall to install a safety overheat thermostat in the inlet hose and they fail restricting the flow thru the core to a trickle therby reducing heat output. does your car have the small metal thermostat in one of the heater hoses with a smaller hose coming out of it ? if yes remove it and use small pipe to reconnect cut hose and see if heat output improves.

also as mentioned in post above ive heard that installing hoses on core backwards can reduce heat output (never experienced it in person though)
in answer to above post the hose coming out of the back of cylinder head should go to the pipe with the control valve in it on the core (which i think is the top pipe)

[E30-Ellerman]

For argon... the top pipe is the outlet house, lower pipe is inlet hose.. top pipe (outlet pipe) runs under the intake manifold to a piece that the thermostat housing bolts to.