dfinnegan

My A/C is not getting cold.

It has been upgraded to R134a and was mildly cold last summer, but now is really not getting cold at all.

Can I recharge the system myself or must a shop do it?

I expect I have a leak somewhere, any tips on finding it?

Thanks,
Dave

Larry Herman

Although the most likely culprit is a leak (and probably from the compressor seal) there could be other reasons that your A/C is not cooling. I have seen plugged filters and even had a stuck expansion valve on my old Carrera. Unless you really understand refrigeration systems, it is not really a do it yourself project. As far as a leak goes though, any traces of oil on the fittings or lines usually indicates the presence of a leak. The best tool to use is an electronic leak detector.

MarkD

"Can I recharge the system myself or must a shop do it?"
You can recharge yourself. R134 and hose etc. is available everywhere. You can even google it and get some pretty useful instructions on many sites.

A leak is another story as Larry mentions above...

dfinnegan

Larry, Mark,

Thanks for the input. I've scheduled a servicing as I expect there is a leak. As my daily driver I'm really going to want the A/C this summer season.

Rennlist rocks,
Dave

Larry Herman

Mark, unless you have a set of gauges, and know what the proper readings are, you can literally explode the compressor like a grenade. If poor cooling is caused by a restriction, and you mistakenly overfill the system with refrigerant, you can get high-side pressures in excess of 450~500 lbs! BE CAREFUL!

LeRoux Strydom

A common leak on the 964 a/c system is the evaporator. The symptoms are how you describe it, with the presence of a oily wet patch underneath the car where the evap drain hose is situated near the fuel pump. It loses pressure over time, and will even tend to "hold" a vacuum when recharging. The leak usually occurs at the copper tube to alumunium tube joints on the evap where 16 years worth of galvanic corrosion took its toll.

It is a bear to replace (ask me how I know) as you have to remove the fuel tank, the fuse box and the complete air distribution box in the front to get to the evaporator. However, it is completely DIY for someone with normal tools and a lot of patience. It took me 3 days working evenings. A search will lead to detailed instructions and pics on the replacement.

Let's hope your a/c leak is somewhere else!! It could also be a hose, expansion valve (accessible from the front without major disassembly) or the receiver/drier.

An R134a recharge should take 850 g - don't know how many ounces that is :-(

Good luck!

MarkD

I bow to your superior A/C knowledge Larry... but in practice I have always recharged my own vehicles with no problems... yet.

I'm off to go whistle in a graveyard

Larry Herman

And you may not ever have any problems. It's just that without really knowing why your system isn't working, it's a bit of a crap shoot. Maybe 99% of the time, it really is just low on refrigerant. It's that 1% that can be trouble.

MarkD

yes, I understand... was just joking a bit.

Larry Herman

Yeah, I thought so. I really wasn't trying to be the prophet of doom, if that's the way I came across.

last toy

I need to replace my compressor. Is it difficult to depressurize the system so I can disconnect the hoses from the compressor. I plan to have a shop charge the system again but don't see a need to pay them to replace the compressor. Looks like a pretty straight forward DIY. Not sure about how to bleed the freon. Any suggestions would be appreciated.

Larry Herman

Now Mark is really going to accuse me of being an alarmist. It is illegal to vent any type of freon into the atmosphere. It is part of a worldwide agreement called the Montreal accord. A shop would reclaim the freon into a canister, filter it, and load it back into your system after the repairs have been made. You probably could get them to remove the freon before you made the repair.

Just for information, there are 2 ports with Schrader valves (like tire valves) that are used for charging and testing the system. They are usually located right on the lines to the compressor. Make sure that neither of them are loose, because the freon would bleed out slowly over the course of a day or so.

Indycam

Hiya Dfinnegan
Do you have ac gauges ? You should get some if you don't and then charge up the thing . Watch over time how long it takes to leak down . If it takes one small can of gas every year , you are golden . If it takes 3 cans every month , time to start looking for the cause . Gas is cheapish and ripping everything apart is not .

Smokin

I bought a set of gauges, a vacuum pump and I have about 15 cans of the old R-12 refrigerant. I also purchased a receiver/dryer as I'm sure the original is in my car. I was going to take it down to the local shop and have the guy eveacuate the system then DIY the rest. I'll change the reciever/dryer and then pull a vacuum. I've never personally odne it but I'm sure it's covered in the manual and/or online. My quick question is... Do I need to add oil to the R-12? As I recall they used to sell the oil charge along side the R-12.

craig001

Yes, if you have the system opened up you should try to drian the oil from the compressor and refill with R-12 oil.