Greetings folks!

My 03' SE7 Discovery has been riding perfectly for the past year and was amazing to have during this past winter up here in CT. My fiancé stole it from me almost every day to get to and from work. I, of course, was left to drive her VW Passat :P.

Prior to winter the AC was working perfectly. I hadn't noticed any leaks and the air was very chilly. Unfortunately, a few weeks ago, I turned on the AC for the first time and only warm air came out. My neighbor, an engineer and familiar with foreign cars, came over to help. We hooked the system up to a vacuum and got no pressure. I may be saying this wrong so please stay with me on this. He mentioned that he was almost positive there was no refrigerant left in the system. I then picked up a few cans and was about to try and top of the system. Instead, we put air into the system to see if it stayed, for about 30mins or so we saw no change in pressure.

He suggested that I don't put the refrigerant in because he was concerned that it may knock loose or break apart the (forgetting the chemicals name) inside the refrigerant drier. Is this possible? I wanted to check here before we tried topping off the system with refrigerant just to make sure it was safe. He was afraid we could really gunk up the system.


The refrigerant I purchased is the UV non-sealing type, so we hoped to put some in and then use a black-light.

Any thoughts?

I'm trying to avoid going to the shop, so any help is greatly appreciated.

Thanks!

Cisco

 

If the system held pressure (you really shouldn't have put air in there - now you really should replace the dryer) you can likely get away with vacing it for an hour and recharging. But even if you don't replace the dryer, you MUST VAC THE SYSTEM. You should be attaching the vacuum pump to the yellow (service) line of the manifold gauge set, open the high and low sides, vac for an hour, shut it down and close the high and low side and see if it holds. If it does not, it's doesn't necessarily mean a leak - you could still have water vapor boiling off. Try vacing for another hour and see if it holds. If you can get it to hold for 20 minutes or so, shut the high and low sides, remove the vacuum pump, attach a can of R134a to the service line, open the valve on the can, and open the low side. Turn the low side off once the pressure equalizes. Now start the truck, turn the AC on high and recirculate, close the windows, blower on high. Put the rest of the can in. Now you need almost another can. You're looking for 22 ounces (if you don't have rear air conditioning).

Here's my tutorial on recharging.

The thing I've seen garage mechanics fail to notice over and over again when testing systems that have lost refrigerant and then pressurized with nitrogen (yes, that's what you should have used) and found the system to hold is the valve cores. If you leave your gauge set hooked up and it doesn't leak, you haven't tested them. They are cheap, so you might want to replace them anyway. Or at least see if it holds before you go filling up the system only to find out that was your leak.

 

What he said. (look up)

 

DaryIJ,

Thanks for the detailed reply. I'm going to print this out and speak to my neighbor. I know we didn't put air in the system, I feel like I'm not explaining this properly. This is a huge help!

Hopefully we can work in this soon since there's a nice heat wave in effect.

I'll keep you folks posted.

 

If he had the stuff you do it, chances are good he knew better and didn't put a bunch of moist air in there from a compressor.

In any case, any time you open the system or it's empty (for an unknown amount of time) it's good practice to change the dryer. They are "one shot" desiccant charges, so if there is any residual moisture you didn't get out with vacing, they'll take care of it. So you SHOULD change it. But you'll probably be fine if you draw a good 27+ inch vac for an hour, considering it sounds like the system hasn't been open to the atmosphere or anything.

But if you did put something other than a dry gas in there, change it. It will work if you don't, but it will chew up the system over time.

 

He probably used nitrogen to preasurize the system' if that is the case there is no need to replace the drier. Pull a good vacum makes sure it hold for a least an hour, before you recharge the system.

 

Any ideas where I can find a new dryer? Just in case I do decide to replace. I took a look over at Atlantic British, but it looks as though they've only got replacements for Discover 1s.

 

LAND ROVER DISCOVERY SERIES II A/C RECEIVER/DRIER 94-02

it looks to be about a $20 item do a google search (thats what I did) pick the closest place to you.

 

By the way, the new drier will come sealed up in plastic, etc. Don't open it up until ready to install, and be quick about it, while open it is soaking up humidity. Some mechanics feel you only have a 10 - 15 minutes working time to get the system sealed back up....

 

That's what is says in RAVE: