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Monovalve replacement

12K views 65 replies 19 participants last post by  Martin_fromGermany 
#1 ·
Hello all.. does anyone have an opinion of MTC monovalves? Did my troubleshooting and narrowed it down to my monovalve on my 28 year old 560SL...I have a lead on a Mercedes OEM Valve for $190..orded an MTC for $27 and just got it today. Easy install, but I think the Valve is defective..Is it worth just biting the bullet and ordering the Genuine Mercedes Valve ? .. don't really want to order another MTC...is is that common that these valves are junk ?...would love your feedback !!
 
#6 ·
I have bad experience with MTC. The spring is too weak and don't stand the pressure of the coolant at high rpm. Several threads on this issue. Best option is to find one at a recycler, since the same type was used in a lot of models.
 
#11 ·
Sorry, I've been meaning to post the results. The BMW mono value didn't work out-of-the-box for me ... there was no heat. I ended up taking the diaphragm and screen assembly out of the BMW valve and putting it into the original Mercedes value, and then it worked perfectly. The MTC valve I had previously installed was junk. The diaphragm tore within two weeks and the spring was weak. The BMW diaphragm is thick and of great quality. It was way more money to sort this than it should have been, but I have perfectly regulated heat again.

One thing I did notice that may help others is that disconnecting the auxiliary heater pump connector prevents water pressure from over-powering the weak MTC value spring. In other words, the MTC value worked fine for me once I disconnected the auxiliary heater pump connection ... at least until the thin diaphragm failed.
 
#13 ·
Thanks for the info sflier.. and to all who commented..I found that the MTC monovalve lasted about 5 days, and the diaphragm ripped.. I did buy and install the OEM from my dealer..$190.00..#000 835 06 44 called "Lffting Magnet" on the box. I also replaced the cabin temperature sensor hose ala the terrific guide that GluekAuf put together. [URL="http://https://www.dropbox.com/s/kardlag0pzlumpi/FullSizeRender.jpg?dl=0"]http://https://www.dropbox.com/s/kardlag0pzlumpi/FullSizeRender.jpg?dl=0[/URL]While I was in there, I noticed that the bottom half of the temperature sensor had separated from the main body of the sensor and was just dangling by itself.(see photo). Someone else on the forum posted a similar photo..sorry I couldn't find it to give him credit..I was able to replace the sensor thru the glovebox with a bit of blind touchy feely stuff..prob easier to remove radio and go thru that way.I used a few different techniques to do this, and hope to post how I did it in a separate thread with some cool photos. All in all, between an OEM monovalve, new sensor hose, and new temp sensor..part# 123 830 05 72.. my climate control system works like a charm. I've never been a great DYI guy, but with the great help from this forum, I'm starting to feel more and more comfortable.
 
#15 ·
Sorry to all ,concerning the incorrect link to my photo of separated temp sensor...doing this on my iPad, and it seemed easy enough to upload pics of my 560sl when I was completing my profile...maybe a "Quick Reply" doesn't allow inserting photos..I'm still new here, so will revisit the tools section before I try another post with pics....
 
#16 ·
Yes, the pump is there to get heat early and to provide sufficient circulation at low RPMs. But, the heater will work fine without the circulating pump running. Best to use an OEM valve, or use the less expensive BMW valve diaphragm with an OEM housing if you have one.
 
#19 · (Edited)
Just had a problem with my 1988 560SL. Ice cold AC but no heat. Bought a monovalve from Napa and it turn out to be one made by MTC. I took it anyway and installed it with the Mercedes spring and tried with it also with the MTC spring supplied. Worked for 10 seconds and quit. Not available through Mercedes anymore, so I purchased today a monovalve from BMW for $140.00 plus tax. Installed it right out of the box and it worked perfectly. Drove it around town for 2 hours today and it's still working. More heat than I'll ever need. Those MTC monovalve definitely need to be banned.... I'm bring the MTC monovalve back to Napa, see if I can obtain a refund.
 
#21 ·
Mercedes mono valve

There are mono valves made available by ECS tuning google it. Comes in a Mercedes box made in France and I just bought one today off their website. The cost was $45 plus the shipping, which in my case was $4.55 so under $50. The boys at w126 forum give great reviews. That is a more realistic price than the dealer inflated prices.

Cheers and merry Christmas ⛄
 
#22 ·
There are mono valves made available by ECS tuning google it. Comes in a Mercedes box made in France and I just bought one today off their website. The cost was $45 plus the shipping, which in my case was $4.55 so under $50. The boys at w126 forum give great reviews. That is a more realistic price than the dealer inflated prices.

Cheers and merry Christmas ⛄
Thanks. I wish I had seen that before I purchased the BMW valve. Here's the link: https://www.ecstuning.com/b-genuine-mercedes-benz-parts/mono-valve-repair-kit/0008350644/
 
#23 · (Edited)
gogi,
Also Good Luck. Please report back after the install. I just called ECS Tuning and there's 7 customers ahead waiting. They say they are trying to get them from Germany. They told me we have them from TMC and I said no thanks and please try not to sell any MTC monovalves to Mercedes Benz's customers. Interesting to see where this goes...
 
#24 ·
Mercedes mono valve.



Ok, so I received my monovalve today from ECS Tuning today after about a ten day wait. What they do is take your order then place the order through their dealer network that's why they take so long. I did get the valve, trying to figure out how to upload more than one photo on this poxy site.
 

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#27 ·
Price of Genuine Mercedes Monovalve

I just ordered a spare Monovalve Repair Kit MB part# 000 835 06 44 for $50 from my local MB dealer, Mercedes Benz of North Olmstead (suburb of Cleveland). At this moment ECS Tuning is selling this part for $231.00. eBay still shows the inferior MTC valve for ~$10-~$40. The parts guy at my dealer chuckled when he looked up the part...not too many months ago they were selling the part for around $254. The guys on the w126 forum have a pretty good thread on this...also found on New Posts for today, p.2 I believe. GET EM WHILE THEY'RE HOT !!!
I'm assuming that Mercedes Benz would not be selling me an MTC part. It's coming from Germany, and my dealer should have it in about 4 days.
 
#28 ·
I just ordered a spare Monovalve Repair Kit MB part# 000 835 06 44 for $50 from my local MB dealer, Mercedes Benz of North Olmstead (suburb of Cleveland). At this moment ECS Tuning is selling this part for $231.00. eBay still shows the inferior MTC valve for ~$10-~$40. The parts guy at my dealer chuckled when he looked up the part...not too many months ago they were selling the part for around $254. The guys on the w126 forum have a pretty good thread on this...also found on New Posts for today, p.2 I believe. GET EM WHILE THEY'RE HOT !!!
I'm assuming that Mercedes Benz would not be selling me an MTC part. It's coming from Germany, and my dealer should have it in about 4 days.
Promising news. I had to bend over for mine.:eek
 
#31 ·
Ive just checked my mono valve repair kit for ECS and it does have MB 30-28 stamped on gasket. BTW I've emailed ECS and asked them what exactly happened over last two weeks that they jacked up prices 500% on monovalves. They reply "we sold those and had to order more from Mercedes they had increased their pricing on them , sorry about that."
 
#32 ·
Ive just checked my mono valve repair kit for ECS and it does have MB 30-28 stamped on gasket. BTW I've emailed ECS and asked them what exactly happened over last two weeks that they jacked up prices 500% on monovalves. They reply "we sold those and had to order more from Mercedes they had increased their pricing on them , sorry about that."
 
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