Air conditioning recharge & oil
 

Hey all

I just used a vacuum pump on my daily commuter - 93 Toyota Camry - to bring the pressure in the system down a bit after putting Stop Leak in it a month or so ago. I believe I put too much in. At the time I didn't have enough refrigerant to refill it, so I postponed finishing the job. Then I started working from home so I haven't had to deal with this recently. But, it's April and beginning to get hot in Texas this year, so I got what I needed and hoped to unclog the main system but keep the leak sealed.

So, vacuumed the empty system a bit, brought the pressure down and put in a can of R12a. Seems to be holding it - but the next few days will tell for sure. That's what happened the last time before stop leak anyway.

So, on to the Ford question.

The 89 F350 460 manual crew cab was upgraded to R134a many years before we bought it. It's got all the stickers etc for the retrofit. And the prior owner didn't do it either - he thought the compressor might be out because it just didn't work. Turns out the electrical connection to the heat/AC controls was fried behind the dash and the compressor is fine.

Now that the new controller is installed & electrical fixed, I believe we probably need to re-charge the A/C system because even though it runs, it doesn't cool at all. Not surprising, since the truck has spent many years of its life just sitting.

So, my question is this - should I vacuum out the system & just re-add R134 or do I need to add oil? If so, how? We're not talking about removing the compressor here, but just a small can into the line right?

The problem with bringing it into the local service garage is the age of the truck. My local Firestone can't handle it because they can't get the parts in general through their official sources. The slightest issue and they charge me but can't actually fix anything.

Thoughts?

If it's been sitting, you'll definitely want to evacuate it. If it's been low or even empty, the low or even nonexistent system pressure may have allowed moisture to enter the system over the years.

You'll want fresh oil for the compressor and then refill with the R134 of your choice.

You may also want to look at replacing some other AC-related components like your drier since the system will be evacuated. Everything else should be fine, but others may have some additional recommendations.

Good luck!

Dealing with leaks in ac with refills and such can turn into a huge pain in the ass. Vacuum pumps get the moisture and refrigerant out, but leave the oil....I'd be conservative on the oil.

You need to put gauges on it to check the pressures and then go from there

I had a local shop evac the R134a out of the system today. They do that free, regardless of which refrigerant is in the system.

I've picked up enough refrigerant + oil, so I plan on putting the manifold gauge on it and get the vacuum pump going for a bit this evening to ensure I've got no leaks.

That's interesting. I wonder how many other shops will do that for free. Keep us posted on how the recharge goes. Which vacuum pump do you have?

Hi,
You might want to get a little dye also!!!

@Glenn54
I was surprised they evacuated for free too. I met one of their employees because they posted stuff on CraigsList, and I picked it up at the shop. I talked with him briefly, then called the shop a week or so later and learned that little tidbit. They do the same with R12.

@seagiant
I just did the dye thing on my other car, and got diddley squat out of it. Literally nothing in the engine compartment lit up except the low side port where it was put in. I got a sniffer now, and that works FAR better at finding where the leak was - which of course was behind the dash on the other car. :( The R12 recovery will come in handy when I go to fix the evaporator in the sedan.

I'd be willing to be that when you take the dash iut to replace the evaporator it will be covered in dye. I've never had luck with the sniffer.

You should replace the accumulator if it's been sitting empty for a long time. Put 2 oz of ester oil in the new accumulator. Then pull the compressor off and drain it and refill with 4 oz ester oil. Then pull a vacuum for 30 minutes minimum and recharge with 44 oz. R134a. Total system oil volume is 7 oz but figure an ounce in the lines.

@jas88
For the previous owner, the truck had been sitting for long lengths of time. However, the A/C system hadn't been used because the heater controls inside the dash had fried and it was unusable. The PO thought the A/C was toast, but the compressor would spin freely by hand. We fixed by replacing the heater control unit only then to learn there was too much refrigerant in the system - it literally would not take any more. That's why I had it evacuated at the shop, and could then continue troubleshoot from there.

@My4FordTrucks
On the sedan, I already know it's the evaporator or at least the connections to it. The sniffer went off in the cabin when I got it inside the glove box. I expect to see dye in the car once I get it open. Hopefully I do not need to do so for the truck.

OK but a new accumulator is cheap insurance (mine was $25) against having a descecant bag fail and pollute your entire system.