H3 won't hold a charge (AC)

[Teahead]

Pulled vacuum.

Let it sit overnight. Held.

Charged it until got about 26psi on cold, about 155psi on hot side.

Air is cold.

Next day...hot air, no pressure on either.



How do I have such a huge leak, but able to hold vacuum????

I had dye in the freon, but seems there's fluorescent dye from when a shop did a coolant leak test, so I have to clean the engine compartment and start over.

 

[JPaul]

Did you try drawing a vacuum again after it leaked out to see if it still holds?

If it is holding a vacuum but not pressure then you have a seal that either is failed in a way that will keep a vacuum but once pressurized will open up, or someone didn't use a reinforced o-ring where they should have when doing work on it before.

 

[Teahead]

Yup.

Did this routine twice.

Tired of wasting freon; especially how hard it is to get these days.

 

[EndeavoredH3]

Time to run some dye and run it again. That big of a leak will be very visible with an UV light after dark.

 

[alrock]

Could be a temperature differential that opens up the leak. Regardless of why there's a leak, like Endeavored said, you just need to find it at this point.

 

[Doc Olds]

FYI when H3s were built, GM put refrigerant dye in the system. All GMs made since 2005/06 have it from the factory. The only time you need to add dye is when you do a flush and vac of the system.

 

[rascole]

Since you already have air in the system. Save the refrigerant until you find the leak. Pressure it up with air and soap test entire system including condenser. 150 psi leak will be easy to spot the bubbles.