348 AC Charging Ports

Hey Jim,

I have a background in HVAC, but I don't want to give too much advise since I'd prefer to see what's going on instead of assuming things and typing over the internet. I'm a little far away so I will try to point you in the right direction.

1. You want to see if you have any pressure in the AC system. A nice manifold gauge set goes a long way. Not sure if you can borrow a set or if you're willing to buy a set. (Plenty of decent ones on Amazon)
2a. If there is 0 (or almost 0) pressure, do not charge the system. There is a bad enough leak and it needs to be fixed properly. Tossing in a charge and calling it good will do more harm than good.
2b. If there still is a decent amount of pressure, turn on the AC and add the 134a to the low side (might have a blue cap or hopefully labelled as such) I can't tell you how much to add because it depends on several factors. I could walk you through it if you had a gauge set and the ability to measure the temperature of the AC line.

Pete

 

For measuring temperature, you'll want something with a probe that can be taped onto the outside of the refrigerant line. Something like this: http://www.elightbulbs.com/Morris-57254-1000A-Digital-Clamp-Meter-with-Temperature-Probe

(Note: I'm not recommending that exact brand or model, I just wanted to give an example)

Can you take a picture of the two fittings? Are they schrader valves? (look the same as your tires valve stems)

When do you plan on doing the work?

Pete

 

That's my car, lol! IIRC, the port facing towards the front is the low pressure side, but please double-check your WSM.

 

If you want, I can get some info together and give you a call over the weekend and walk you through it. It'd much easier than typing back and forth.

 

Looks like you still may be running R12. You need to see if someone updated the system to R134a before pumping it in. Also, your R134a gauges will not fit those ports. You will need R134a adaptors to have the gauges fit. If the car is still running R12, you will need to change the oil in the compressor and replace the receiver/drier before installing the R134a.

 

You can find them in most auto stores for around $5. Not a big deal if your system is already set up with r134a. Make sure you pull a good vacuum on your system for at least an hour before charging. After you have pulled a good vacuum on the system, let it set for at least 5 minutes and check to see if the vaccuum level has decreased. If it does, you have a leak. You should pull a vacuum up to at least 25 inches of mercury. 30 is better.

 

It will not hurt anything to just add some freon and try it. But if you add it and it does not cool down as it should, you need to evacuate the system and pull a vacuum on it. If you have an air compressor, you can pick up an A/C vacuum unit from Harbor Freight for $20. It uses air flow to pull the vacuum. You may also be able to rent an A/C vacuum pump from an auto parts store. But try adding some first. Remember that your system will take less r134a than r12 so do not overfill it. Remember also that with r134a, you do not go by the site glass. There will still be some bubbles in the site glass even after it is fully charged. The whole system will only need around 3 cans max so I would not put in more than 1-1/2 to 2 cans on a refill. Read the gauges carefully so not to overcharge.

 

Jim, was your car converted to R134a? I ask because I ran R134a for a few years without updating the o-rings, etc, and it never ran as cool as with R12 (it can't cool the same volume as efficiently as R12). Also, the molecules in R134a are smaller than R12 and with the perosity the coolant leaks out of the system much faster than with R12.

The dirty little secret is R12 is still readily available in the US if you know where to look. I recently had my system vacuumed out, a few o-rings replaced and then recharged with R12. It runs so cold now it frosts up the windshield. Just my 2 cents if you are looking to get the most out of your A/C.

 

Yes, I just underwent a similar situation. I was looking at changing over to R134a but found a local supply of R12. Afterwards, I was able to hang meat in the cockpit.

 

Screw a fan to the dash put it on full blast. the ac works like arse when on hi & sounds like a motorboat ......in my 348 that is !I m looking foward to getting a 360 to get good ac!

 

I am not sure what is happening with your A/C but mine will freeze you out. I went out today for almost 2 hours. It was 97 degrees here in Oklahoma with high humidity. I set my thermostat to 70. I had the fan on low (only showing 3 bars). I was just fine the whole time and could not hear the system working. Just to test it, I cranked the thermostat down to Low. It did not take long before I was freezing and had to turn it up.

 

FWIW, my a/c freezes my ass off too. I have R134A in my a/c system.

 

Ahhhhhhhhhhhhhhh, the importance of owning a set of a/c gauges. Tells you exactly what is going on!!!!

I would replace the drier, of course. But if you need it over the weekend then you may have to just place it in the oven. Let it sit for a min or so to cool off before fitting the hoses to it. Dont want the orings to melt to it.

See Todd's post here in regards to a new $10 348 a/c drier.

http://www.ferrarichat.com/forum/showpost.php?p=140484962&postcount=368

Sounds like there is a blockage or a stuck TX valve in the system. The high pressure switch is cutting out the compressor so you dont blow anything up.

I would remove the TX valve and inspect mate.

Either way, do what you have to do to get it going and then when you come home, dump the gas, fit new drier, vac the system and refill with gas.

You REALLY need to vac the a/c system to remove the moisture mate.

For optimum a/c performance and longer component life.

 

You missed my last posts in the parts exchange sticky above. I found a replacement drier for about $15. Also, sometimes when the refrigerant is low, it can also freeze up the system. It may be worth throwing in one can to see what happens.

 

Oops! you beat me to it PAP! To fast for me.

 

Too fast for most they reckon.

 

That's what she said.