What's the purpose of the ball in the monovalve?? I get that it prevents backwards flow of water, but is it's job also to slow water flow the other direction????


Reason I ask, I'm ditching mine and I've got a BMW water valve going in it's place. Then I started wondering if I needed to add some kind of flow restrictor and check valve.

So here is what's in the works. I have now got my AC system working again and I'm putzing with the stupid monovalve. I've read the horror stories about this thing and seen the 300dollar option.
One of the guys over at the other forum had a newer ML something and he grabbed a 16buck BMW valve on amazon and a 15buck connector and installed it in place. What happens when you do this, you find out pretty quick the valve gets stupid hot. I had the same thing happen with a brass valve I bought. Even though they only draw 1 amp, this isn't good. Anyways, adding a 4.7ohm 10watt resistor does the trick and keeps the valve safe.

SO this got me thinking about the ramifications about ditching the monovalve and it's ball feature. Ya kinda need that ball to prevent backflow and I think it might actually slow water flow by providing some restriction. Then I saw it. I think the solution is leave the OEM monovalve in place and down where the stupid pump lives, install this bmw substitute and park the resistor by the toaster. What sayeth the peanut gallery? Any big deal ditching the electric pump on the w123? I have a new pump that I haven't installed yet and it appears my OEM monovalve is working fine since I changed the seals in it. With all that, I still don't have much faith in the monovalve.

This just seems like an affordable solution to me. Call me whatever, but I find 250bucks a bit steep for the only plug and play solution currently on the market. If it was 180bucks, I'd *****, but I'd probably buy it and be done with this BS.

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