The shop says I need a new pump but I see there are a lot of these o-rings on ebay. Is this o-ring failure common? If any have changed it one bolt holds the reservoir in place along with the )-rind as it slips the reservoir into the pump. If anyone has changed this o-ring how difficult/easy and a part number as I would think what you guys use is the same as what my MB needs. I want to try the o-ring before I change the pump. Thanks! Mark

 

I cannot help you with the O-ring part number but when you take it out you can measure it quite easily. You can buy a replacement at industrial supply house among others as well as dealers. You want the dealer supplied one as long as it is for continuous high temperature use. You want one made from Viton, not some cheaper material. Measure the outside diameter of the groove it fits in and the cross sectional diameter of the O-ring.

 

Since your car is 2 years older than any of ours, I say you are pretty much a pioneer for what degrades with age.
I wouldn't be surprised if you have O-ring degradation, and replacing it is a lot cheaper than the whole assembly.

 

replace the reservoir, it has the filter in it that is due for being changed after 14 years

reservoir = $40.00
gasket = $3.50 (may come with the reservoir, i don't remember offhand)

 

Thanks Rob. I am not a trusting guy whern it comes to shops. I'd rather take a shot at the O-ring. Add a new reservoir also. Sweet