How do you leak test a drained (empty) AC system?

[joecap5]

Is there a way to test for a leak in the AC system if the system has already been drained?

The compressor seems to be locked up because the car stalled out immediately when the AC is turned on and I could smell burning belt. So I couldn't test for leaks with the system running. Probably should have tried the test before the system was drained even if it was not running but too late now.

I'm doing a heater core replacement so I have access to the evaporator. I'd like to test it to see if there is a leak before I put everything back together.

If you're not familiar with what's involved in a heat core replacement which would be very similar to an evaporator replacement check these DIY:

• http://forums.vwvortex.com/showthrea...eater-core-DIY
• http://vincewaldon.com/index.php?opt...d=32&Itemid=28
• http://forums.vwvortex.com/showthrea...ngine-with-A-C
• http://jettajunkie.com/vw-jetta/show...r-core-romoval

I could just go ahead and replace it but a new evaporator would cost $200 at germanautoparts.com so I'd like to avoid the expense.

[sic_null]

I've never done this. So it's not for sure. But I would imagine that you could plug the outlet. And rig up a fitting of some sorts from the inlet to an air hose/compressor/pump. And spray it with soapy water and look for leaks/bubbles

I would only put 15-20 psi in it tho. Considering its a low side component and normally only gets 35-40psi of refrigerant.

[richardf8]

The compressor seems to be locked up because the car stalled out immediately when the AC is turned on and I could smell burning belt.

I am confused a bit. If the compressor stalled the engine when the AC was turned on, that would imply the clutch engaged. If the clutch engaged, that would imply that the high and low pressure sensors were giving acceptable outputs, which would imply that the system is holding a charge. So I'm not sure why you are concerned.

I could just go ahead and replace it but a new evaporator would cost $200 at germanautoparts.com so I'd like to avoid the expense.

What's 200 dollars compared with the prospect of ripping the dash out again to replace an evaporator which may, although still intact, yet be reaching the end of its service life? I know $200 is a lot to spend on an "as long as I'm in here" repair, but when getting in there is that much fuss, it may nonetheless be worthwhile.