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Finding and testing Heater Valve

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Boggie
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Finding and testing Heater Valve

Post by Boggie » Sun Feb 04, 2018 10:54 pm

Hi All,

After servicing the car I brought the old girl up to temperature for the first time today. All seemed well with no leaks, no exhaust smoke and a nice smooth idle. However I am getting no heat in the cabin. First point of call is to check the heater valve operation and wiring. Can anyone help me with where it is (the photos in the manual are not clear) and what checks I can do please?

Is the heater temperature control in the cabin is simply a rheostat that applies a varying voltage to the valve, controlling how much hot water is sent to the matrix? Is the valve serviceable?

Thanks,
Ian
1985 M635CSI
Classic Car Collector & Restorer.

ron
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Re: Finding and testing Heater Valve

Post by ron » Mon Feb 05, 2018 8:32 am

Boggie wrote:
Sun Feb 04, 2018 10:54 pm
Hi All,

After servicing the car I brought the old girl up to temperature for the first time today. All seemed well with no leaks, no exhaust smoke and a nice smooth idle. However I am getting no heat in the cabin. First point of call is to check the heater valve operation and wiring. Can anyone help me with where it is (the photos in the manual are not clear) and what checks I can do please?

Is the heater temperature control in the cabin is simply a rheostat that applies a varying voltage to the valve, controlling how much hot water is sent to the matrix? Is the valve serviceable?

Thanks,
Ian
Ian,

Put "heater valve" in the"search" box.
They are ALWAYS rustier than you thought!!!!!!
'88 High line.
'85 M #228
'85 M #207
'80 735i

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Boggie
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Re: Finding and testing Heater Valve

Post by Boggie » Mon Feb 05, 2018 1:52 pm

Yes, of course. I did that last night and after trawling the results I found out some of what I needed but not where the actual valve is. I am guessing behind the dashboard somewhere but was hoping somebody might be able to help me.

Thanks,
Ian
1985 M635CSI
Classic Car Collector & Restorer.

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603racing
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Re: Finding and testing Heater Valve

Post by 603racing » Mon Feb 05, 2018 2:19 pm

I believe they are all in the same location, regardless of sub model. If so, it will be located towards the center of the car from the brake booster, in the engine bay on the firewall.
'85 635csi - Dark Shark
'13 Jeep Wrangler
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ron
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Re: Finding and testing Heater Valve

Post by ron » Mon Feb 05, 2018 2:38 pm

On the engine firewall.
P1020573.JPG
P1020573.JPG (4.65 MiB) Viewed 1003 times
P1020572.JPG
P1020572.JPG (4.64 MiB) Viewed 1003 times
They are ALWAYS rustier than you thought!!!!!!
'88 High line.
'85 M #228
'85 M #207
'80 735i

Pod
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Re: Finding and testing Heater Valve

Post by Pod » Mon Feb 05, 2018 4:27 pm

I think I've still got a couple of service kits available if you need one.

LarryM
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Re: Finding and testing Heater Valve

Post by LarryM » Mon Feb 05, 2018 6:04 pm

I've recently purchased two new heater valves from the dealer, and both of them leaked profusely. These are now made in China. A rebuild kit is the way to go, at least until BMW realizes the quality control problem and corrects it.
1985 635CSi
1987 535is
1965 Impala SS

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Boggie
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Re: Finding and testing Heater Valve

Post by Boggie » Mon Feb 05, 2018 7:20 pm

I love you guys! Thanks so much.

The BMW tech I spoke to this morning said I have to remove the lower dash and centre console to get to the valve and reckoned I was looking at about a 4h round-trip to replace it. 603racing and Ron, your info and particularly the pictures helped me find my valve and you were both spot on; it is on the bulk head in the engine bay. A little hidden and harder to get to on my car due to the M88 engine's larger head and intake side but definitely much better than stripping out the dash and console!
Pod; you have mail!

What a great forum, Cheers!
1985 M635CSI
Classic Car Collector & Restorer.

Pod
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Re: Finding and testing Heater Valve

Post by Pod » Tue Feb 06, 2018 7:39 pm

PM sent😉

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TN_M6
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Re: Finding and testing Heater Valve

Post by TN_M6 » Tue Feb 06, 2018 7:54 pm

This topic gets a lot of attention at mye28.com, it's a big problem.

I think others have seen similar with new from BMW valves being cheaply made also. Costly and not good.
The repair kit we find here is MTC brand and typically only lasts a couple seasons (if you are lucky) But at least it's inexpensive so order a couple.
Some are using an e46 valve but it takes some extra plumbing to make it work.
Last I remember someone may have discovered a Mercedes valve or kit that works better.
It's all there on mye28.

In a pinch you can remove some of the guts of the valve and put it back together with the housing seal in place but the heat is always on then. Fine in cold winter weather and I've done that.

Another piece of advice. Before you service it remove the radiator cap to relief any pressure in the system, better yet apply a slight vacuum to the system, remove cap while warm, replace and then wait for it to cool a while... Or use the radiator vent hose and a vacuum source. If you do that I have been able to service the valve and not lose much more than a few drops of coolant.

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Boggie
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Re: Finding and testing Heater Valve

Post by Boggie » Wed Feb 07, 2018 11:44 pm

Thanks. Good advice.

I have bought a service kit from Pod and hope to have it this weekend, alone with a full new set of coolant, vacuum and breather hoses. the engine is stripped of throttle bodies, plenum, all hoses and intake tubes ready for a refurb and refit this weekend (hopefully)

Ian
1985 M635CSI
Classic Car Collector & Restorer.

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Brucey
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Re: Finding and testing Heater Valve

Post by Brucey » Thu Feb 08, 2018 5:50 pm

just be absolutely sure to use the correct spacers and wave washer under the insert to make sure that the new parts seal correctly and make a good seal onto the valve body. The most common source of leaks is a failure to fit these parts correctly.

The current shite BMW parts may well be a manifestation of the same thing; repair kits from BMW have come without the wave washer or the spacers recently and if you are daft enough to do that you might build a complete valve with these parts missing too...duh!. :roll:

cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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