After 10 ys and 155kmiles, I took my trusty MB to the local MB for an AC recharge. I was told that both the high side and low side schraeder valves would not seal after the tech attempted to add freon, and both needed to be replaced at an estimated cost of >$200.

Is this a common failure mode?

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Tom Latos
2002 E320
1995 E320 Sold at 288kmiles

I would try replacing the Schrader valve stem internal valve first. You will need to remove/recharge the system for this procedure. That may be where they are coming up with the high $$ amount.

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Jim

A couple of thoughts.

The valve cores are essentially the same thing used in your tires. The old one just unscrews, and the new one screws in. When I went to get new ones for an a/c project, the shop just gave them to me; they aren't worth charging for.

Assuming the system is discharged, changing both cores requires, oh, approximately two minutes. No, wait, I'm being too pessimistic, make it one minute.

There are tools out there which can be used to change the valve cores without releasing the refrigerant. Do some browsing on http://www.acsource.com - I think they have an example there. Of course, with the recovery machine all shops now have, it's really no work to take the refrigerant out of your system, change the valve cores, vacuum the system, and then recharge it. That shouldn't take more than 30 minutes, with about 25 of those waiting for the vacuum pump to do its job.

Final thought. The valve cores aren't really expected to completely seal. A good set of caps for the service ports is really what keeps the refrigerant inside. The valve cores only have to be good enough to not let the refrigerant out between the time the charging hoses are disconnected and the caps are reinstalled.

How much do you trust this shop? 'Cause frankly it sounds a little like they're scamming you.

- JimY

Well, here is the deal. When I got home tonight I printed out a couple of procedures from the 124 CD AND I took a look at the leaking schroder valve. It was leaking alright - the high side fitting - so I took a small key and depressed the valve and walla - it seated properly and stopped leaking. So I recharged the system with about 1 lb of 134a and am now happy as a clam!

I can't wait till tomorrow when I call my "favorite" MB shop - Napleton's in Rockford, IL, and tell them it will not be necessary for them to plan on seeing me on the repair.

I can't say enough how much this forum has helped me enjoy my E320 - and control maintaince costs. Thanks to all

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Tom Latos
2002 E320
1995 E320 Sold at 288kmiles