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bigboystoy
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Location: Melbourne, Australia

Heater valve repair

Post by bigboystoy » Wed Nov 13, 2019 4:57 am

Been doing a lot of research on this topic and all the forums seem to just come to an end with no suitable conclusion.

My issue started with no heat over 80kmh but after dismantling the valve to see what the issue was, I've now got heat all the time. Bugger.

I thought the solution was to install an ebay always open solenoid as suggest elsewhere but I found this didn't work after a couple of minutes (think the on/off pulses were too fast). So, this has been confined to the bottom drawer.

There appears two options. Original BMW $$$part or the cheaper MTC replacement valve. There's even a suggestion they are both from the same manufacturer. Is the MTC worth the money? Some say junk, some say good and some say you have to use some of the original washers to make it work but don't give any specifics. Being in Australia, any part will need to be ordered so I'd prefer to do this only once.

Success and failure stories both taken onboard or is there a fully workable solution? Which ever the result, I will post a conclusion once the value is fixed and working. For now, the heater core will be bypassed.
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1979 Volvo282GT
1988 Porsche 944S
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Brucey
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Re: Heater valve repair

Post by Brucey » Wed Nov 13, 2019 10:59 am

my POV on this is that the MTC kit is so cheap it is worth a punt.

You definitely need to reassemble the valve with all the same parts as it came with originally, which means yes you need the washers etc if the kit comes without them.

I've seen more valves that have been 'repaired' badly than I have seen ones which have been repaired successfully. Once the valve leaks the usual responses are

a) that it is a problem that can be solved by using gallons of silicon mastic or
b) that the parts in the kit are somehow faulty

or something. The least likely things that folk think are
c) I left parts out
d) I put parts in the wrong order
e) that the parts are not seated correctly

etc etc yet these are the sort of things that happen.

I don't remember anyone coming up with really good systematic reasons (like the parts are made of material that isn't up to the job, or are made to the wrong size) as to why the cheap kits don't work, and in fact there are multiple similar reports that the official BMW kit 'doesn't work' either, suggesting that the most common fail is simply misassembly.

So I'd give a cheap kit a punt; just be careful with how you put it all together again; if you don't build the assembly to the correct dimensions, re-using washers etc where necessary, it won't work.

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

bigboystoy
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Re: Heater valve repair

Post by bigboystoy » Wed Nov 13, 2019 11:13 pm

Ok, good start.

What your saying seems to mirror what's on all the forums. Its just seems strange that a supposedly simple repair can be plagued with such failures. Its certainly not that valve failures are an isolated fault, so how can the repair be so hit and miss.

Still happy to hear any other comments
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1979 Volvo282GT
1988 Porsche 944S
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songzunhuang
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Re: Heater valve repair

Post by songzunhuang » Wed Nov 13, 2019 11:19 pm

bigboystoy wrote:
Wed Nov 13, 2019 11:13 pm
Ok, good start.

What your saying seems to mirror what's on all the forums. Its just seems strange that a supposedly simple repair can be plagued with such failures. Its certainly not that valve failures are an isolated fault, so how can the repair be so hit and miss.

Still happy to hear any other comments
I found a repair kit from Pelican Parts that was from Euro. I know, Euro stuff normally is terrible, but this was a rubber diaphragm with a few clips, how bad could it be? I installed it in my car and it's worked so far. I will say the heat coming out of the vents is not as pronounced, but at least when I turn the heat off, it is actually off, allowing my A/C to do it's thing.

In any case, the kit I found:
URO Heater repair: https://www.pelicanparts.com/catalog/Su ... HT_pg1.htm

It's not like the MTC in that it uses the original plunger. Hop to the link and you'll understand. I also put a few pictures and observations in my project repair thread.
-----
Song Huang
1984 633CSi
Last 7 of VIN: 6997383

bigboystoy
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Location: Melbourne, Australia

Re: Heater valve repair

Post by bigboystoy » Thu Nov 14, 2019 8:52 am

That repair kit I haven't considered, but it seems I have two issues. The first being the no heat over 80kmh (suggesting loss of spring tension), and now heat all the time (because the rubber collar has completely torn.

I'm leaning towards the MTC as I still have to consider postage (why is postage from USA so expensive?). Lucky for me the weather is warming up so time is on my side.
Past toys:
1979 Volvo282GT
1988 Porsche 944S
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1986 635 CSi

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nick88highline
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Re: Heater valve repair

Post by nick88highline » Thu Nov 14, 2019 9:29 am

bigboystoy wrote:
Thu Nov 14, 2019 8:52 am
That repair kit I haven't considered, but it seems I have two issues. The first being the no heat over 80kmh (suggesting loss of spring tension), and now heat all the time (because the rubber collar has completely torn.

I'm leaning towards the MTC as I still have to consider postage (why is postage from USA so expensive?). Lucky for me the weather is warming up so time is on my side.
I would strongly recommend finding an original French made Behr valve, as I did. Not sure if the repair kit BMW sells is still made in France. The complete water valves are now made in China and having disassembled one, I would say they simply cannot work due to missing springs and washers.
Nick
BMW 635CSiA (1988)
BMW i3 (2016)
Jeep Grand Cherokee V8 (2000)
Morris Minor 1000 (1968)

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Brucey
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Re: Heater valve repair

Post by Brucey » Thu Nov 14, 2019 9:34 am

IIRC the 'no heat at speed' symptom is usually a small leak in the diaphragm. At low engine speeds the valve can work even if there is a little damage, but at higher (engine) speed the flow conditions in the valve change and any tiny fault is more apparent.

FWIW the valve works on the pilot principle; the springs in the thing don't often cause problems (except sealing if you leave the wave washer out of the assembly)

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

songzunhuang
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Re: Heater valve repair

Post by songzunhuang » Thu Nov 14, 2019 6:43 pm

bigboystoy wrote:
Thu Nov 14, 2019 8:52 am
That repair kit I haven't considered, but it seems I have two issues. The first being the no heat over 80kmh (suggesting loss of spring tension), and now heat all the time (because the rubber collar has completely torn.

I'm leaning towards the MTC as I still have to consider postage (why is postage from USA so expensive?). Lucky for me the weather is warming up so time is on my side.
Oh, I neglected to note your location. Yea, that would be painful shipping. I have come across people on eBay advertising "New Old Stock" original BMW units. They are about $300 USD, but at least you'll rest assured that it'll likely work well for a long time. In fact, if my URO part fails, I'm just going to get an original "New Old Stock" unit.

These eBay units are coming from Lithuania and they are marked as "Free Shipping". Maybe it'll be a wash?
https://www.ebay.com/itm/GENUINE-OEM-BM ... SwX5ZbCE7Z

Anyhow, I'll report back if anything changes on my repair. It's getting a bit colder in California now, but that just means 50 degrees at night.
-----
Song Huang
1984 633CSi
Last 7 of VIN: 6997383

bigboystoy
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Location: Melbourne, Australia

Re: Heater valve repair

Post by bigboystoy » Thu Nov 14, 2019 9:01 pm

Yes, the joy in living in the land down under. The $30 USD MTC part from Pelican Parts turns into $100 AUS by the time you factor in the exchange and shipping. Even with the complete valve, the $300 USD turns into $450 AUS even with free shipping. Whichever option is going to hurt the hip pocket.
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Brucey
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Re: Heater valve repair

Post by Brucey » Thu Nov 14, 2019 11:57 pm

https://www.amazon.com/MTC-3065-Mercede ... B00BCR2Y0E

shows as $16.83 plus $5.14 shipping, no taxes, when I enter 'ship to Australia'.

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

bigboystoy
Posts: 61
Joined: Wed Feb 13, 2019 4:22 am
Location: Melbourne, Australia

Re: Heater valve repair

Post by bigboystoy » Fri Nov 15, 2019 3:32 am

Wow. Ok. Didn't even think of Amazon. Here Amazon has no automotive products on their local site, and for a lot of things Amazon US will not ship to Aus so didn't look.

Assuming their pricing is USD, better paying $35 AUS.
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jps635
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Re: Heater valve repair

Post by jps635 » Fri Nov 15, 2019 7:25 am

I suggest do this.

Buy the MTC kit like Brucey says. (didn't work for me but now I know more)
Inspect the rubber bits (diaphragm and seal).
Thoroughly clean your exisiting valve body, washers and diaphragm / screen assembly.
Note the order of the washers
Remove the rubber bits from the MTC kit and replace those on your original plunger assy as there will unlikely be anything wrong with the mechanical bits and they will be superior quality.
Apply a smear of rubber grease to the diaphragm and seal outer (contact) edges
Carefully replace the full diaphragm assembly into valve body and reassemble and be sure it seats properly. (Test by sucking/blowing)

Stay away from the junk replacement valve assembly at horrendous price made in China as sold by PP/TMS. Using the original bits you should be confident the thing won't leak even if you continue to have heat issues.

Note the heater control module also takes inputs from the cabin air temp sensor and a thermometer measuring air exit temp from the heater unit, however only start looking at these if the you know the heater valve is functioning properly.
'85 635csi JPS (RA2-66)

bigboystoy
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Location: Melbourne, Australia

Re: Heater valve repair

Post by bigboystoy » Mon Nov 18, 2019 11:01 pm

So while I'm waiting for the valve to arrive I've been trying to test the wiring for the valve.

My car is a 1986 and the wires to the valve are brown/green (BN/GRN) and green /black (GRN/BLK). When ignition is on, and testing just the wires to the valve (but NOT connected) my readings are:
Dial on full cold BN/GRN - 3.16v GRN/BLK - 12v
Dial just off full cold BN/GRN - 0v GRN/BLK - 12v
Dial at full hot BN/GRN - 0v GRN/BLK - 12v

My testing also showed the BN/GRN is not connected to earth thru the range of dial movements, so I'm not understanding the switching that makes the valve open and close. I understand there is a temp sensor in the drivers footwell that is also part of the system.

Is there a simple explanation of how the system operates or a link to a site that does. And what of my readings above.
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Re: Heater valve repair

Post by jps635 » Tue Nov 19, 2019 7:28 am

See attached
Attachments
IMG_3772.JPG
IMG_3772.JPG (94.15 KiB) Viewed 502 times
'85 635csi JPS (RA2-66)

bigboystoy
Posts: 61
Joined: Wed Feb 13, 2019 4:22 am
Location: Melbourne, Australia

Re: Heater valve repair

Post by bigboystoy » Thu Nov 21, 2019 3:48 am

Hey thanks, great diagram.

Ok, so the system works on each component using the -neg as switching. Easy enough to understand. It now has me wondering if the readings I'm getting as described previously are correct. I should be seeing an earth on the BN/GRN wire but I'm not. Maybe I'm not testing correctly.

Is there a publication on how to test the system components without an operating valve?
Past toys:
1979 Volvo282GT
1988 Porsche 944S
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1986 635 CSi

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TBM
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Re: Heater valve repair

Post by TBM » Thu Nov 21, 2019 5:30 am

jps635 wrote:
Tue Nov 19, 2019 7:28 am
See attached

Love this JPS! Do you have other systems for the car laid out like this? pretty please!
'84 M635csi
'86 Lotus esprit Turbo (sold)

bigboystoy
Posts: 61
Joined: Wed Feb 13, 2019 4:22 am
Location: Melbourne, Australia

Re: Heater valve repair

Post by bigboystoy » Mon Nov 25, 2019 11:54 pm

Ok, so got the MTC valve. Picture speaks volumes for the quality of the item. The bulge in the mesh I had to move around in order to get the small washer to sit properly.
Valve Quality.jpg
Quality control is questionable
Valve Quality.jpg (54.22 KiB) Viewed 393 times
The other issue I discovered was the size of the main washer on the MTC valve. Mine measure 31mm in diameter Vs 30.25mm for the original stuffed item.What this meant was the washer wouldn't properly seat in the valve housing base so I lubricated the washer to help it seat properly.
Valve base.jpg
Valve body seating position
Valve base.jpg (77.11 KiB) Viewed 393 times
One site I did find useful was MyE28.com. The links below give great write ups of repair.
http://www.mye28.com/viewtopic.php?t=58033
http://www.mye28.com/viewtopic.php?f=9&t=17342

Everything went together properly and with everything wired up and the car warm all I get is hot air. Bugger.
As time has been against me, I closed the valve using the 12v wire (GRN/BLK) and earthed the other side of the valve. This shuts off the valve whilst driving, and shows the valve is working properly. Looks like i have more searching for a fix when time permits.
Past toys:
1979 Volvo282GT
1988 Porsche 944S
Current toy:
1986 635 CSi

baders
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Re: Heater valve repair

Post by baders » Thu Nov 28, 2019 1:31 am

bigboystoy wrote:
Mon Nov 18, 2019 11:01 pm
So while I'm waiting for the valve to arrive I've been trying to test the wiring for the valve.

My car is a 1986 and the wires to the valve are brown/green (BN/GRN) and green /black (GRN/BLK). When ignition is on, and testing just the wires to the valve (but NOT connected) my readings are:
Dial on full cold BN/GRN - 3.16v GRN/BLK - 12v
Dial just off full cold BN/GRN - 0v GRN/BLK - 12v
Dial at full hot BN/GRN - 0v GRN/BLK - 12v

My testing also showed the BN/GRN is not connected to earth thru the range of dial movements, so I'm not understanding the switching that makes the valve open and close. I understand there is a temp sensor in the drivers footwell that is also part of the system.

Is there a simple explanation of how the system operates or a link to a site that does. And what of my readings above.
This sounds like the heater regulator unit may not be properly grounded ? This is something you can easily check at terminal 3 of the heater regulator (BR wire).
1986 635csi LOCUTUS / Arktis Blau Metallic / Pearl Beige / S38B36/ Close ratio dogleg 5sp
2002 E46 M3 / Topaz Blau Metallic / Black Nappa / 6 speed SMG software tuned / Bilstein PSS10 Coilovers

bigboystoy
Posts: 61
Joined: Wed Feb 13, 2019 4:22 am
Location: Melbourne, Australia

Re: Heater valve repair

Post by bigboystoy » Wed Dec 04, 2019 11:19 pm

Thanks for the suggestion on the possible problem.

As I recover from a knee reco, how hard is it to get to the temperature regulator. Just wondering if its something that can be done whilst I'm layed up. Is it straight forward or one of those PINA jobs requiring reasonable flexibility and mobility in which case it'll have to wait.

I've done a search but cannot find anything specific on the process.
Past toys:
1979 Volvo282GT
1988 Porsche 944S
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songzunhuang
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Re: Heater valve repair

Post by songzunhuang » Sat Dec 07, 2019 8:24 am

nick88highline wrote:
Thu Nov 14, 2019 9:29 am
bigboystoy wrote:
Thu Nov 14, 2019 8:52 am
That repair kit I haven't considered, but it seems I have two issues. The first being the no heat over 80kmh (suggesting loss of spring tension), and now heat all the time (because the rubber collar has completely torn.

I'm leaning towards the MTC as I still have to consider postage (why is postage from USA so expensive?). Lucky for me the weather is warming up so time is on my side.
I would strongly recommend finding an original French made Behr valve, as I did. Not sure if the repair kit BMW sells is still made in France. The complete water valves are now made in China and having disassembled one, I would say they simply cannot work due to missing springs and washers.
Nick
Well my URO rebuild unit hasn't gotten better in weeks and as it's getting colder, it's clear that it is not working well.
I broke down and purchase an OEM unit from FCP Euro. It was $159 on sale and it is marked "Made in France" so I guess that's a good sign. I've posted pictures in my project area. I'll report back when I get a chance to install it.
-----
Song Huang
1984 633CSi
Last 7 of VIN: 6997383

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