AC compressor engages but no cool air.

Does your engine fan come on?

 

The sticker on my truck was for 3.5 pounds R134. I found a recall notice online and the amount was changed to 3 pounds for my model. The air is colder with 3 than 3.5. Don't know why. Other owners of the same model mentioned the same in an online forum.

 

You don't have to take it to a truck shop. Call around the automotive AC shops around and see if they'll look at it. It will probably be cheaper than a truck repair place. Find one with as close to 5 stars as you can on Google, read the reviews. They specialize in this kind of work, that's all they do day in and day out, so you can be pretty sure they're going to do it right. If you need a part, they'll get it from the dealer, just like they have to do with cars.

You can get tools at Harbor Freight, but you're going to spend like $200 between a gauge and a vacuum pump and you still have to figure out what you're doing. You're not going to be able to recover the refrigerant, and venting it to the atmosphere is not proper. If this is something you think you'll be doing a lot for other people or on other vehicles, maybe go this route. But I wouldn't invest in tools for a one time job.

 

Not to be a wise cracker, but I like reading HVAC posts. There is never a shortage of well intentioned, misinformation. For one, as far a leak detecting dye is concerned, I wish everyone that used it would tag the system warning that its in there, so I will not work on it and avoid ruining/contaminating my expensive equipment with it. Dye may be fine for a desparate attempt at locating the first leak, but then it gets eveywhere on all tools and under the hood, like anti seize. The gift that keeps giving. Any reputable shop should be using nitrogen charges to locate leaks. There are two things that belong in a properly working HVAC system an that is oil and freon.

 

Anything that doesn't come in a can contains pag oil.
That pag oil contains dye.

If you can't handle green freon. You probably shouldn't mess.

Green is the nature of the beast.
Pretty much every vehicle will be green.
Pag oil is green.


3.5 pounds is too much. Overcharged. That's why it doesn't blow as cold. It needs to be exact amount. Or it won't be cold

 

I remember when the dryers had that eye glass on top. Once the bubbles cleared, it’s full.

 

Tha

Thats right. Didn’t need no freaking gauges. Vacuum pump, What’s that? Lol. On my first Truck, if all refrigerant was lost, I’d slap a new dryer on as quickly as possible. Let it pick up any moisture. No vacuum, just fill with proper amount. It worked fine. I’m sure it wasn’t 100% efficient, had some air in the system. But it worked pretty good. Compressor lasted 1 million miles. Might be able to get one with a sight glass still. I don’t know. The one on my Truck has one. Its purpose is to tell if it needs replacing. It turns color when bad. I’ve had a tech tell me they don’t always replace it unless needed. For $30 I replace them anyway. My best friend was a hvac tech. He finally convinced me of the importance of vacuuming the system. One tiny frozen bit of water can cause a sticking expansion valve, he was right, it eventually happened. Also moisture can possibly cause rust in the system. I think the oil fight against that. But not going to argue with a Pro. All I know is just enough to get it working myself when in a jam. Got tired of $600 repairs early on. Except for the 1 million miler, which ran up north, the longest compressor life I’ve gotten is my current one. It ran about 4 years. Probably because I replaced the whole system, properly vacuumed. It’s bad now. I typically expect a problem every year or two. Given the mileage an OTR truck runs, can’t expect much more. Cost of shop work is out of control. All over the board. Unless it’s someone you know, it’s easy to get raked over the coals on A/C work. I’ve saved Thousands over the years.

 

A pump has always been needed for best results.

I was disappointed when 134 came out with no glass. Specially since in the beginning it operated at much higher pressures then it does today.

Today it means nothing. In either world.

When epa made us get certified. They taught 100 + outside temperature for r12. On the high side.

I found 125 was better.

 

Ok. That explains a lot.