A/C Evaporator inspection and removal
 

Hey fellas,

I need to check the evaporator and the expansion valve area for leaks - I'll be looking for the die using a blue light. I'm currently in the middle of removing the lower half of the evaporator tray inside the cab (under the pass dash). The three clips that hold the two halves together were removed as well as all securing nuts. The lower half "wants" to come out and there is a snag. The condensate drain hose was removed as well.

-Is it possible to even remove the lower half of the evaporator tray?
-Do I need to remove the high and low pressure lines gong through the firewall into the evaporator in order to do this? I wouldn't think so....

Before anyone asks, the compressor, drier, condenser and all O rings have been replaced. But I still have a leak somewhere :mad:

Thanks for any insight.

Ali
'92

Regurgitation of the service manual.
 

I broke out the service manual, and it only describes removing the entire cooling unit. And the exploded diagram is kind of vague on where everything goes.

The lower case only snugs up against the housing for the hoses, so it's not truly "attached" to it. There is a large oval gasket, but it looks like it goes inside the lower case fitting, and not over it.

It appears the expansion valve fits in a socket on the lower case and then a small run of tubing for the high side runs up to the hose housing. If it is still attached, this would keep it from coming apart. It has two nut style fittings: A female with gasket on the expansion valve side, and a male fitting on the hose housing side. By hose housing, I mean the oval assembly that attaches to your bulkhead/engine firewall where the engine compartment hoses attach.

Theres also a fan control amp that is attached to the lower case with one small screw. But it doesn't seem in the way... except of course for the outside electrical connector. It will just come out along with the lower case.

The diagrams do show the lower case as a completely separate piece.

I've personally never been in there, so I wouldn't know for sure.

But....... The only place you could have a leak inside the cooling unit would be at the expansion valve, or the tubing (connectors on both sides) coming off of the expansion valve, or on the test fitting soldered on to the large tubing (Low pressure side) coming out of the evaporator, and all four of these can be seen through the opening. Only the insulator on the large tubing would have to be removed to glance at that particular test fitting.

If the evaporator unit itself is compromised and leaking... Well.. That's another story. But what's the chance of the actual core having a leak? Of course, I'm asking that rhetorical question with absolutely no experience, but it doesn't seem to be reasonable for the core to spring a leak.

All other fittings and "normal" leak areas can be seen through the opening. :)

How fast is it leaking? If it's relatively fast shining the UV light in the drain hose might be the answer.

Evaporator leaks aren't uncommon but we haven't been hearing of it being a pattern problem w/the SVX.

Phil,

Thanks for the insight. Can you tell me where you're looking at in the FSM? Specifically which book and what page would be great. I think I'm in the same page but just want to make sure.

If it's the expansion valve leak then that's an inexpensive replacement. However, knowing me, I'll just replace both parts since everything else was replaced as well.

Beav,

I lost brand new R12 in about two weeks :mad: I'll look up at the drain hose. Thanks for the idea.

Ali

Check the hoses to the manifold fitting at the rear of the compressor very closely. I've found a couple that like to seep there, especially after the compressor has been moved around.

Oh.. cool, it's still sitting over there on the same page. :)

It's in the sections 4/5 book. Section 4.7. I derived most of the info from page 59 which has an exploded view of the cooling unit, and then the removal instuctions on pg 58, and dissassembly on pg 60. All from section 4-7.

How many o-rings did you change? When I converted mine to r134 I found 13 of them.

I remember reading your thread...I had 11 O rings. When/if the expansion valve or evaporator come out, I'll replace the remaining rings. In any case, nothing inside the engine bay is leaking. There was no die to be found anywhere so I'll move my search to the evaporator area. It probably is the expansion valve but I'll check the drain hose per Beav to rule out the Evaporator.

Thanks.

Ali