I have inspected both monovalves that have gone bad this year. There appears to be a small tab on the inside of the rubber gasket, and both valves tore exactly on this spot. The new valve (installed yesterday, and working perfectly) also has a tab which you can feel through the rubber. I am wondering how long this one will last. I'll try and post a phot as soon as I figure it out.

The MTC monovalve costs approximately $36. The OEM (Benz) is $138.

Jon--

Importec in their European catalogue (not worldpac) sell it for $16.23, and Shane is really good about getting it shipped ASAP.

Seeing as though I just changed one as well, I'm interested to see if the one I installed rips--suggesting a manufacturing issue. . .

G

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Laugh if you will, I had this happen on a customer's W126 and it was low on coolant....

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Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

Our web host sells it for $15 last time i looked. Next time when it happens again, feel and clean inside the monovalve. Maybe there is a burr or rust. In my experience, the OEM will last over a year. The MTC one around 3 months and i set the temp at either max cold or heat so the monovalve wont be oscillating all the time.

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'85 300D Cal 280,000 miles
'14 GLK 350 60000 miles