AC not cold after sitting + engine work???

[boy&hisdogs]

1998 K1500. Before the truck was parked the AC worked OK. It wasn't ice cold but it was definitely working, and has been the same way for years.

Then it developed a bunch of issues that left it parked and not running for about a year. After trying my best I still couldn't figure it out and had to take it to a shop where they had to replace the cam and a bunch of ignition parts. I asked them and they said they were able to do all the work around the AC parts and never had to drain the system.

I got one of those DIY refill canisters and when I hooked it up the gage on the can said that I still has freon. It didn't have numbers on it, just low/correct/high coloring. It would go between low and correct as the compressor cycled on and off, and the compressor seems to be cycling on and off as normal. I ended up not using the DIY refill and returned it since I don't really know what I'm doing here.

Just now I cleaned out the evaporator box under the dash. It wasn't as bad as some I have seen but it was definitely very dirty, lots of pine needles and fine dust.

AC is still not blowing cold. It's cool-ish but that might just be because the truck is sitting in the shade and it's a mild day.

Is there anything else I should check before bringing it in to check/fill the refrigerant?

 

[Erik the Awful]

Check your condensor in front of the radiator. Are the fins straight and clean? Or is there a layer of fuzz and leaves on it?

Check your evaporator drain and make sure it's not plugged, but usually this will result in water dripping on your floorboard.

How often is your compressor cycling on and off?

 

[boy&hisdogs]

Check your condensor in front of the radiator. Are the fins straight and clean? Or is there a layer of fuzz and leaves on it?

Check your evaporator drain and make sure it's not plugged, but usually this will result in water dripping on your floorboard.

How often is your compressor cycling on and off?

Condenser looks good, clean and straight.
Evap drain is functional. Sometimes I do get water on the floor after a hard rain but I cleaned it out yesterday and sprayed a lot of water through there to be sure and it drained fine.

The compressor clutch is engaged for 2 seconds, then off for 5 seconds, and repeats like clockwork. This is with AC on full cold and fans on full blast.

 

[Erik the Awful]

That's cycling pretty fast. I'd strongly suspect a low charge. I wouldn't trust the gauges on a parts store "recharge" kit. If you're feeling froggy, you can get a set of gauges and check both the high and low pressures while it's running. You can get a set of cheap gauges for $35 on Amazon, but as a hobbyist I'd go with the Harbor Freights for $65. Fortunately I still have my Blue Point gauges from when I was a tech.

If you're not interested, take it to a reliable shop.

 

[boy&hisdogs]

That's cycling pretty fast. I'd strongly suspect a low charge. I wouldn't trust the gauges on a parts store "recharge" kit. If you're feeling froggy, you can get a set of gauges and check both the high and low pressures while it's running. You can get a set of cheap gauges for $35 on Amazon, but as a hobbyist I'd go with the Harbor Freights for $65. Fortunately I still have my Blue Point gauges from when I was a tech.

If you're not interested, take it to a reliable shop.

Thanks for the help. I took it in and the refrigerant was low because the compressor is leaking. I have to say I'm not that surprised. When I bought the truck it had no refrigerant in it at all. I had it charged at the dealership back then and they said they couldn't find a leak. It lasted for several years but was never quite as cold as most other cars.

Now I know, and hopefully I'll get another decade out of it again.

 

[HotWheelsBurban]

Yup, short cycling is often a sign of low charge. I need to look at that on my crew cab; it takes a little while to get the cab cooled down. Of course it is bloody hot in Houston now so that ain't helping....

 

[boy&hisdogs]

Yup, short cycling is often a sign of low charge. I need to look at that on my crew cab; it takes a little while to get the cab cooled down. Of course it is bloody hot in Houston now so that ain't helping....

It's worth a look, my ac now blows colder than ever

 

[Erik the Awful]

I had it charged at the dealership back then and they said they couldn't find a leak.

Dealership technicians don't get paid for diagnosis. They only get paid for swapping parts and recharging the system. They're also under incredible pressure to constantly bring in more profitable work. If they can't find the leak in five minutes, they're just going to charge the system and charge you. They don't care that their "fix" doesn't last, because there's another sucker out there.

 

[boy&hisdogs]

Dealership technicians don't get paid for diagnosis. They only get paid for swapping parts and recharging the system. They're also under incredible pressure to constantly bring in more profitable work. If they can't find the leak in five minutes, they're just going to charge the system and charge you. They don't care that their "fix" doesn't last, because there's another sucker out there.

All the more reason to support local shops. I know there's good and bad everywhere but I've had overwhelmingly better experiences with local mom and pop places vs chains and dealerships.