Low side O ring

Car is a 1996 base model and right now I have a problem that I just cant seem to fix and have been spending way too much money on it. I just put in a brand new evaporator and expansion valve, hooked up the low and high side hose to it with brand new O rings fitted on the evaporator. Still have a huge leak right at that O ring spot and dye is just dripping out like crazy. The low side hose I already replaced and has no leaks. It just keeps leaking from that one connection. Does anyone have any ideas? Summer time is here and I cant keep driving around in 97 degree weather with no ac.

Is the (expansion valve = filter/dryer) a big canister with a little glass window?
Did you get a stock or aftermarket one?

the receiver drier is on the driver side near the headlight. Yeah it has a glass window. I got 1 from rock auto but it looks wrong and I havent put that on yet. the expansion valve sits on the evaporator which is inside a black box located behind the glove box and under the dash.

Well if dye is literally dripping out then it’s not a small leak.

Can you take the hose back off and inspect your work? I expect a damaged o-ring or burred bore or the like. I’ve seen new evaporators leak. Not just at the tubes, but sometimes the connections are bent/damaged and will not seal, they disform the o-ring.

EDIT double check the oring size too

The problem is I dont have an O ring that fits on the evaporator. So no matter which o ring I put on. Its either too big or too small. Its literally the only thing stopping my ac from working right now lol.

Well that explains why it’s dripping and so easy to see! I’ve spent hours looking for AC leaks and they’re usually one of two kinds: I get a big clue with oily spots or dye, or I don’t get any clues and it’s a very hard diag.

So - if you know you don’t have the right size o-ring, what can we help you with? Can you bring the two orings you have to a parts store and get a few in between those sizes?

I see, sorry for that somehow I was reading one thing and thinking of another.
Have you tried calling the dealer and I think this is the part that you need… MB946449
unless something else is wrong except the O-ring.
They have been discontinued but some may still be in stock
O-Ring, A/C, 1/4 - Mitsubishi (MB946449)

  • Replaces:MB276658
    If not, I believe that it’s a 1/4 inch diameter but don’t know the thickness.

yeah called 2 dealers, both said its discontinued. Bought multiple o ring packs, no luck.

Do you remember what size you have installed?

I gotcha now.

I would run with those part numbers Lex just gave you, or if you run into problems call a dealer and get a p/n.

Just two days ago I replaced the transmission temp sensor and wire harness on my truck and it was a discontinued part, but the dealer gave me the p/n and i found it aftermarket.

Once you find the correct p/n you’ll know for sure the diam and thickness and you can get an o ring for sure.

These are the part numbers i got from one of the sites i called and I ordered 2 o rings per part number. Though when i called my local dealer and gave him the part numbers he said they were wrong. I guess ill find out when they arrive. These were the part numbers I was given.

Yeah I think we are on to the solution here. Please post the p/n and any relevant data when you do find out because it sounds like others will encounter this as well.

If your dealer said those are the wrong numbers I sure would have liked them to tell me what the correct numbers were so i could write them down just in case.

The many parts for these cars have been discontinued but other Mitsubishi models may use exactly the same parts but under a different part number. Hopefully that is the case…
Good Luck.

Just got the o rings and neither of them fit. They were both way too small. They sent me a diagram of the evaporator and it doesnt even show part numbers for the o rings in the picture ill post below.

Does it need to go into that big hole?

Im trying to upload a pic but this site wont let me upload pics for some reason idk why


As you can see the bottom O ring is too small. That O ring is 3/4 of an inch.

So not standard, it needs to be a bit bigger ha?

Yup but I cant find a part number on it, I also cant find any O ring that will fit. Its basically the only reason my ac doesnt work. Changed the evaporator, the low side hose. But i dont have an o ring that will fit there.

Would you be able to post a picture of the other piece that connects to this?