Air conditioning not cooling. Is it the evaporator leaking since nothing else appears to be?

Joined
May 24, 2019
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250
Location
Ontario Canada
Two years ago, I had the AC system on the LeSabre recharged and it ran beautifully for two years, but this spring it has started to run warm again and no air conditioning cooling is happening now. They checked every part of the system when they charged it two years ago including opening up the wiper assembly. At the time, they could not find any leaks anywhere with either the die test or the leak detector. The shop that does this kind of work for me has now gone over the system again this week and they cannot find any leaks anywhere and are suggesting it could be the evaporator. Note that the evaporator is the only part of the system that is not easily accessible and the labour costs or couple of hundred dollars in order to get access to it. I can still find replacement evaporators for this system including an AC Delco version. But my question is, if I go forward and get the evaporator replaced, is there any other part of the system that could be leaking? They have checked every other part of the system including the compressor which is original and all else seems to be working just peachy. I am looking at about $250 labour to open up the old evaporator and then another $150 or so for the new evaporator. FYI, the leak must be extremely small because it took two years for it to impact the temperature of the air cooling. What would you do?
 
Small leaks can almost be impossible to find. Try some refrigeration stop leak name brand like rectorseal. Its not cheap the size u need is by tonage but it displaces oil so 10% of oil volume ( flows with the oil).
 
I think it's unlikely to be the evaporator coil as it's in an area that is protected from the elements.

More likely is the Schrader valve or an o-ring. If the cannot find a leak then replace the Schrader valve and o-rings.
 
If you have the black light to detect the dye-look, at night, at the condensate outlet where the water drips out when it’s running, and at the front of the compressor. I bet you see dye somewhere!
 
I think it's unlikely to be the evaporator coil as it's in an area that is protected from the elements.

More likely is the Schrader valve or an o-ring. If the cannot find a leak then replace the Schrader valve and o-rings.
Evaporator leaks are quite common. Leaves and trash fall down there and eat the aluminum core.

But the leak could be anywhere.
 
On the LeSabre the most common thing that leaks is compressor clutch seal. Very hard to find unless you can look at compressor for oil in the front. It will get worse but I would top off every 2 years and not worry until it gets worse. Wait until you have to fill every 6 month.
I was going to say… I’d check the manifold at the compressor and the clutch.

Otherwise evaporator is a decent bet unfortunately. If the leak is that slow, it might be worth trying the right amount of leak seal, if there is no intention of having a pro touch the car, or replacing the evaporator.
 
I think it's unlikely to be the evaporator coil as it's in an area that is protected from the elements.

More likely is the Schrader valve or an o-ring. If the cannot find a leak then replace the Schrader valve and o-rings.
Good idea. They have checked all of these areas such as the Schrader valve. Its a very reputable shop and they say they've not found any leaks anywhere with either dye tests or the 'Sniffer' which leads them to think it's the Evaporator. Still, as others have said, 2 years is a long time for a leak to run before impacting the temps coming through the vents inside.
 
Labor will run approximately $300 and I've found a few sources for a replacement evaporator. Most are "no name" brands or brands I don't recognize. Surprisingly, I DID find an AC Delco unit on Amazon as well as JEGS. Prices are quite diverse as you can see from these 2 links. I'm in Ontario so will be paying in Canadian $. FYI, I've noted the REALLY poor reviews of JEGS so this may explain the 'too goo to be true' pricing there. I also found it a bit odd that if I purchase this at amazon.com instead of amazon.ca, they will sell to me and ship for less than at amazon.ca and the price is less since the $130 converts to $246.46 with duties in Canadian $.



 
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I think it's unlikely to be the evaporator coil as it's in an area that is protected from the elements.

More likely is the Schrader valve or an o-ring. If the cannot find a leak then replace the Schrader valve and o-rings.
I saw the O ring and gasket kit for the AC system. Wow, I had no idea just how many seals (and potential leaks) these systems can have! :rolleyes:
 
I'm surprised recharging at home doesn't help if a shop recharged 2 years ago and it was fine. Case in point, my neighbor has a 94 Mustang that we top off each spring. No notable leaks, but it still maintains 30psi of static pressure, so we know it hasn't sucked in air or humidity. What kind if pressure does the system have today? If its zero, it could be more of a problem. If its holding some pressure, it should be able to be nursed back to life. You might need to put a full set of gauges so you can see what the high side is doing or not doing.
 
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