A/C troubleshooting

So I did a vacuum test and after 1 hour it went from 30 to about 27. I thought hmm maybe I didn't do it right so I did it again for 2 hours and it didn't appear to drop, if it did, maybe by 1. So I let the vacuum run for an hour and I just closed the system off, I made sure everything was tight when I closed it off. I'll check in 2 more hours to see if it holds pressure. Odds are I have a leak and that's why there is no coolant. If it drops again I guess I'll recharge and add uv dye to find it.

 

So I let the vacuum sit for 3 hours and zero drop. I'm surprised but I'm not gonna get my hopes up. Tomorrow or the next day I'll add coolant and uv dye so if there is a leak I will find it.

 

I just finished charging the system with r134a and see UV dye. She blows coooooooold now.

I put a vacuum on the system yesterday and it was at -30 before I drove it today. Before I recharged the system it looked like it was -26. Does this confirm a leak or is it normal after turning the car on and driving for that pressure to change a little?

 

You’ve got a leak.

 

That's what I figured. Just interesting how it didn't drop for 3 hours in a vacuum but then after 24 hours it dropped by 3-4. That seems to be a pretty fast leak too. Im assuming this system will be out of gas again in like 10 or so days if the going rate seems to be 3 lbs of pressure every 24 hours. Hopefully I put in enough dye to detect it easy.

 

Makes sense to me - it'll leak faster when there's more pressure in the system. Buy a new Denso expansion valve and drier at the very least and replace all your o-rings.

 

UPDATE

2 weeks later, the A/C still blows pretty cold. I figured enough time has passed so if there is a leak, I should spot it. So I went out last night and used my UV light to detect leaks in the engine. I didnt see any UV dye anywhere. Im highly skeptical of the results. I mean the system had to have a leak somewhere in order to run out right? My other 2001 tacoma has never been charged and still runs super cold. Maybe not enough time has passed. I wonder if its the Evaporator under the dash that could have a leak. What would I need to open up on the Evap in order to see where it would leak if it did fail?

 

You'd pretty much have to pull the entire evaporator out of the truck. You may be able to separate the housing a bit to get a flashlight in there but it'd be tough.

 

Sometimes it will come out of the drain with the condensate if it's leaking, alot of times you will smell it inside too after it sits awhile on a hot day and you turn it on.

 

Okay, we will try that when the truck returns from the shop for the new wheels and nitto tires mounting and balancing. Haven't checked the belt for sometime now, hope it's just loose.

 

was there an update on the leak?

 

Truck still has coldish air over a year later. I'm sure there is a slight leak cause it's not as cold as when I first put it in. It will buy me enough time till I decide what I actually want to do with it. Right now I'm not too concerned.

 

This right here.

I had a similar slow leak in the evaporator and it was hard to detect even with dye in the system. Finally showed itself when inspecting the condensate drain tube at night (while the A/C was running). It might help if you can collect some of the condensate to look for that glow under the uv light.

I thought my A/C troubleshooting was lengthy at a couple weeks. But a year… I might just top it off annually at that point.

 

Ya that's why I think I'm just gonna let it go till I decide if I want to do. It still blows relatively cold but not in the 40s like at first.