AC system exploded!

I was idling my car today with AC on high to load/warm the engine. All of a sudden...POOF! I thought the coolant expansion tank exploded.

But, it turned out to actually be the AC line (and spewed the yellow gunk in my engine bay). The failure happened right next to the firewall where the electrical connector plugs into the aluminum AC pipe.

Is this a known failure point? I was surprised it popped there because it looked like new...no corrosion or anything. Is it common for AC systems to explode like this?

That's a new one on me...

Yeah me too! I rarely ever use the AC other than to defog my windshield... So I'm not too bummed over it. I might just delete it altogether.

That's not a known failure point. The high pressure relief valve is on the compressor. Sounds like the pressure switch failed.

BTW, if the AC system ever vents like that get away from the car. You don't want to breath in all the R134a/oil.

-J

Yeah I definitely got away from the car...that stuff is nasty. It took quite a while for it to stop hissing...

What could cause the pressure switch to fail? Is there a fuse that may be blown?

Generally the pressure switch is tied in with the A/C circut and doesn't have it's own fuse. One of the fail safes didn't do their job.

Did you see a hole in the metal line anywhere? Bulged?

Thought maybe something was chaffing on it for awhile and it finally went, but that's an odd spot. Can you get us a pic or two?

Generally if there is a pressure issue the compressor will fail first. The line failing may have just been random. I would get the line replaced or repaired if you can.

At the failure point there is no visible defect. No bulge or corrosion. It looks normal. The pressure came out where the plastic interfaces with the aluminum. Radiators with the platic end tanks seem to fail the same way...at the interface between materials. I guess it was just a defective part.

First, if the ac had yellow dye in it, it's someone working on it trying to find a leak. Who knows what parts he replaced with. OEM? CRAP?

There is a pressure relief valve built into the compressor It looks like a bolt, but has a small aluminum seal over a lead melt-out plug. It usually blows around 350-400psi. If a system overpressures, that is where it is supposed to blow.

Apparently, you have a new, but ineffective replacement line. I'd be looking for something OEM or there are several quality aftermarket makers of AC lines.

Yes the stuff looked like yellow foam. Similar to "great stuff" foam in a can.

I'd also check fan operation. With no air coming across the condenser at an idle internal pressures can increase. As mentioned the PRV should have vented but I would still check for proper fan operation to be on the safe side.

He might have just been seeing the oil boiling out.

-J