Heating Issue

[t_marat]

Hi!

I have a problem with the heating system. When the engine temperature gauge is in the middle range, there is still no hot air in the heating system. Only when I put the sliding bars (controls on the panel) to only blow at the windshield that the hot air starts to come, but only at the driver side (only cold air on the passenger side). If I put two other sliders to also blow air, everything coming out is not hot (cold air). Though I should say that my temperature control of the passenger side does not work, it just slides in itself with no fixation. Air conditioning is off.

Another thing is that hot air does not blow when the engine is very close to normal temperature, even if I set it to blow only at the windshield. Hot air starts to come out only when the temperature gauge is in the middle, and some time passes. One guy says this is due to the water valve (thermostat) not openning when it should. Attached is the picture of that water valve and link to realoem drawing. http://www.realoem.com/bmw/showparts.do?model=HB51&mospid=47370&btnr=64_0114&hg=64&fg=18

I have flushed the engine cooling system.

Hope my explanations were clear enough.

[pundit]

Faulty heaters valves become a fact of life sooner or later.
The valves should remain fully open (max heat) when no power is applied.

First of all check the voltage supplying both heater valve coils with the motor on and the heater set to fully cold. You should measure 12 volts.

When turning the heater to full hot, you then should measure zero volts.
That will at least confirm the problem lies with the heater valves themselves.

What causes them to stick is are internal rubber seals designed to keep water out of the solenoid coil mechanism. These seals eventually disintegrate and as the water gets into the solenoids sludge and corrosion develops causing them to jam.

They can jam in any position hot or cold. If you give the top of the valves several sharp taps with the handle end of a hammer they may free up and function normally again for a while. Mine did but in the end I still had some heated air coming from the passenger side vents and as it's summer here now I decided to replace the valve assembly which has fixed the problem.

Shogun had some good pics a while back of a disassembled heater valve.

Shoguns thread is here...

http://www.bimmer.info/forum/showthread.php?t=16409

The seals that go bad are shown clearly in this picture...

http://www.bimmerboard.com/members/shogun/original/heatervalve4

Er...sorry about the free ad for the other forum... :p

You may still have other issues but if the heater is hot when it's turned off, or cold when it's turned on, provided the measured voltages are correct, then you have a faulty heater valve.

[Dan in NZ]

You mention you flushed the engine cooling system. If this problem started just after you did that, then it's likely you have an air pocket in the heater circuit. Do a search for bleeding, and welcome to the frustrating world that is bleeding an E34...

[t_marat]

That problem was there before the system flush.

If the water valve was not openning, does it mean that the flushing liquid did not reach the heating radiator?

[pundit]

That problem was there before the system flush.

If the water valve was not openning, does it mean that the flushing liquid did not reach the heating radiator?
Yes, but try giving the heater valves a sharp tap as already mentioned.
If you disconnect and reconnect power to the heater valve solenoids you should be able to hear a sharp click as they open and close.
If you hear nothing as you do this that means either the valve is seized or the solenoid has failed.
How dirty was the original coolant when you flushed the system?

[t_marat]

The original coolant was not dirty at all. It was I think bluesh one. I don't know what brand it is.

[632 Regal]

one valve is for the drivers side, the others for the passanger side, that might be an issue.

[t_marat]

Will this valve fit my car:
http://cgi.ebay.com/ebaymotors/Heater-Mono-Valve-for-BMW-3-0-525-530-535-540-i-M5-E34_W0QQcmdZViewItemQQcategoryZ33548QQitemZ8022320 585QQrdZ1QQsspagenameZWD1V

How is the price? This seems not to be an original part.

[pundit]

Will this valve fit my car:
http://cgi.ebay.com/ebaymotors/Heater-Mono-Valve-for-BMW-3-0-525-530-535-540-i-M5-E34_W0QQcmdZViewItemQQcategoryZ33548QQitemZ8022320 585QQrdZ1QQsspagenameZWD1V

How is the price? This seems not to be an original part.
Looks like the correct valve.
Original part uses solenoids made by Bosch. It could be an OEM.
The price looks okay providing the quality is good.
I think the normal price in the U.S. is around $150.00

[Bill R.]

correct valvehttp://www.bimmer.info/%7Ebill/heatervalve.jpg





Will this valve fit my car:
http://cgi.ebay.com/ebaymotors/Heater-Mono-Valve-for-BMW-3-0-525-530-535-540-i-M5-E34_W0QQcmdZViewItemQQcategoryZ33548QQitemZ8022320 585QQrdZ1QQsspagenameZWD1V

How is the price? This seems not to be an original part.

[mohsinkhalid]

i had this problem before but i live in the country and i had a mouse nest back behind the blower,or another option you mite have a vacuum leak and the little doors that send your heat and cold air are not opening or probably the heating / cooling switches check them if they are working properly.