99 S70 - It's summer annnnnd my AC isn't cold anymore

[Auburn T5]

Well we got it figured out. It wasn't the evaporator (thank goodness) but rather the pressure switch had warped.

http://www.fcpeuro.com/products/volvo-a ... h-30767231

A pleasantly nice quick fix and the ac is ice cold now.

My mechanic took a peek at the evap from behind the glove box and he said it still looks to be in great shape.

He did discover that the exhaust manifold gasket is coming apart and I've got a leak there (which I kinda was guessing but he confirmed) so I'm going to be getting the copper gasket, an R manifold and *maybe* an ARD spool control 19T and tune

First order of business before I go there is to get some supplemental transmission cooling in place.

[abscate]

Nice. I did my evap core on my 1999 last year, and held my breath this year the first time I punched the AC button - and it works great.

I have been spoiled my new-to-me P2 car which kicks out almost 50F of AC temp differential - it is ice cold.

[erikv11]

Nice easy fix, good to know about the pressure switch.

Just FYI, the mechanic can't tell anything by looking at the evaporator core. Even when it is leaking he can't tell anything unless he uses tracking dye. Clearly yours is not leaking and that's good news, but still keep the usual close eye on it.

[abscate]

You can actually see the track of a leak in the evaporator without dye because it will bring some PAG oil with it. Any greasy residue is either dead rodent or leaky AC. If it doesn't smell, its leaky AC. Once the grease gets on the evap core, hair and dust stick to it and it will look furry. If it has eyes, it might be a dead rodent...Swedish mouse or Norway rat..

Dye (which you can buy as R134A+dye at an auto parts store, will be easier to see.

[Auburn T5]

^ yeah my mechanic mentioned the oil thing. He says that he typically replaces about 8~10 evap cores every year once it starts getting warm outside and people with old volvos start to discover their AC doesn't blow cold anymore.

He did say it was the first time he'd ever seen a pressure switch warp like that. The fitting that screws into the AC line was no longer perfectly round.

[erikv11]

... Just FYI, the mechanic can't tell anything by looking at the evaporator core. Even when it is leaking he can't tell anything unless he uses tracking dye. ...

You can actually see the track of a leak in the evaporator without dye because it will bring some PAG oil with it. ...

Aha, I didn't think to look for PAG oil residue. Makes good sense, thanks for the info guys!