Greetings all!

I just replaced my leaking exp valve, and am not sure if the two plates on either side of the valve are supposed to sit flush with the valve or not. The O-rings went just inside the valve, but that's it. I should've taken a before picture for reference.

If someone could review pic below and tell me if it looks OK, I'd appreciate it! I don't want this to leak

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-Paul-
'01 E430, Sport 72,000 mi
'98 C280, 126,500 mi

Paul,

I just went out and looked at mine and it appears to be much tighter than that.

The proof is in whether or not it leaks. Have you tried to draw a vacuum and see if it will hold the vacuum?

Hope this helps,

Hey thanks Larry for taking the time to compare yours! The system is closed and ready to be vacuumed and charged, so tommorrow it's off to AutoZone to grab a vacuum pump.

Tommorrow should be a great day to uncork some freon as it'll be about 82 and balmy down here in Houston.

Thanks for the reply!

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-Paul-
'01 E430, Sport 72,000 mi
'98 C280, 126,500 mi

Paul,

When I reread my post I saw that my wording might not have been clear.

My expansion valve looks tighter than yours. Make sure the o-rings are the right size and are slipped in place up to the shoulder before sliding the tube into the valve.

I should have proofread what I wrote.

Good luck,

Larry, I read your reply and knew what you meant so I didn't chime in.

Paul, I looked at mine, too. My gaps are equal on the front and back but not nearly as wide as the ones in the photo.

I would check it again before charging. I replaced mine once and had to fiddle with it to get it to settle in just right.

Is that the original evaporator?

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2012 E350
2006 Callaway SC560

Thanks Larry and Brew ---

I slapped some Nylog on the O-rings and seated them all the way back on each hose line, and like you Brew, I had to fiddle with it to get it to go in as far as I got it. (found it surprising)

I'm starting to wonder if the dealer parts woman gave me the correct o-rings (size was correct but they were dark green and very hard and un-elastic -- unlike the HNBR type)

I'm not sure if that's the original evap or not B -- but it is reassuring to see those copper fittings.

I'm going to pull a vacuum today and see what happens.

Thanks again for the help!

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-Paul-
'01 E430, Sport 72,000 mi
'98 C280, 126,500 mi

Paul,

To do a gross leak check with the least trouble, simply pull a vacuum for five minutes or so, then close off both low and high side of your manifold and see if it will hold the same vacuum for a minute or two. If it does, then go ahead and do a thorough evacuation. If it's going to have a sizable leak, you don't have to completely evacuate to tell, and that way you won't waste your time on a full evacuation only to find that something needs attention.

Good luck,

I've been through 124 expansion valves a few times, and it looks OK to me. Pretty impressive photo for such a tight spot!, BTW.

I can see the suction line is seated in the ex. valve all the way up to the shoulder, with the o-ring hidden from view. This is how mine seats as well.

The o-rings are just standard metric sizes, so it's very unlikely you have incorrect sizes.

Colors of o-rings don't mean anything. Usually HBNR is light green, and blue or black are neoprene. But not always... Either neoprene or HBNR should be fine for an R-12 or R-134a system.

Give it the old vacuum test as Larry described. The proof is always in the pudding. One caveat. I presume the system has been used recently, and that you've not completely flushed all the old oil and replaced the drier? If so, you can expect the vacuum gauge to not hold steady after a short evacuation. Here's why. Refrigerant is disolved in the oil inside the system. It will stay there a surprisingly long time, even with the system open to atmospheric pressure. As you pull a vacuum on the system, the refrigerant will start to come out of the oil. If you give it sufficient time, enough refrigerant will be released to affect the vacuum reading. I find it takes 2-3 hours under full vacuum to get all the refrigerant out. After that, see if the system will hold vacuum long term.

- JimY
- JimY