Tallguy67

Hey folks,
It has been a while since I have been on here and I can't imagine anyone will have a magic answer but it cannot hurt to try. We are finally getting warmer up here in southern Alberta and today I did my annual top up of refrigerant. I have had a slow leak somewhere as long as I have had the truck. When I popped the hood this year the little black cap that keeps debris out of the low pressure Schrader valve was missing. I really didn't give it a second thought. I put in a can of refrigerant, pressures were good and the temps from the vents were all within spec. I put the truck away in the garage and went on to the next job. 10 minutes later, DW went out to the garage and came back 30 seconds later to let me know that the truck is hissing. Sure enough the refrigerant was leaking out the low pressure Schrader valve. I have put the coupler that I have on and off a few times in hopes that there was just a piece of something in there that I could manage to blow out of there. No joy, as fast as I add refrigerant, when I take the filling coupler off, out comes the refrigerant.

Does anyone have any suggestions? I really don't want to turn this into a $1,000 job.

sherod

I've never tired, but can you use a tire stem tool to unscrew the valve?

My only thought other than try to cap it, but i bet it's some "special" size.

Tallguy67

Sherod, after I posted I realized that I can probably pull the valve core and either clean or replace. This does mean that I need to buy a vacuum pump though to evacuate the AC system fully once I pull the valve. I have avoided AC work for years because I don't have a vacuum pump. Time to pull the trigger on the pump. I can get one from Amazon.ca for $250 with 3 days shipping free.

VADSLRAM

If you don't leave the valve out for too long you will be fine, no need to pump it down afterwards.
There will be enough outgassing to keep miniscule positive pressure at the valve and the valve itself is so small. You get more air in the system by not flushing the hose when you added the freon.

Tallguy67

I found a vacuum pump with all the hoses etc for a reasonable price. I am picking up up the valve removal tool today for $10 and I found a local refrigeration place that has valves in stock for not much money either. The only option at the dealer was to replace the whole refrigeration line and that was going to get spendy and be a big job.

Seeing as I got a good price for the pump I am actually happy to have it. I have avoided AC work in the past due to not having the pump. I know I have a slow leak somewhere (hence topping up the refrigerant yesterday). Now that I have the pump I will likely start looking for the leak to solve the problem once and for all. If the ongoing leak is a hose, I will deal with it. If it is the evaporator, then I will just keep topping up each year until I have to get to the heater core for some other reason.

BTW - the valve will be out for at least a day as I have to take it with me to get the replacement, the refrigeration shop doesn't know the actual size, so they need to see my old one.

gorms

My local Napa had those caps in stock, or see if you can borrow one from another car while the valve is out. Napa also had the lines for pretty cheap, took a little tweaking to get them lined up perfect but they were no more then $50 USD.

VADSLRAM

I had to replace this hose last year because my bypass oil hose rubbed through the aluminum part. They had it in stock and with Military discount it only cost $80. It came with orings, valves and caps.
List: A/C Hose Assembly - 1999 Dodge Ram 2500 | O'Reilly Auto Parts

Tallguy67

Note to others - make sure you have actually drained the pressure in your AC system before you start unscrewing the Schrader Valve. If you do not follow that step, things start to get messy in a hurry. I only got minor frost bite but I now know exactly what color the dye is in dyed replacement refrigerant...

Experience is an effective teacher.

sherod

I can imagine you jerking around and trying to screw it back in yet keep out of the blinding spray! Seems like what I would do!

Hope you had safety glasses of some kind on!

Tallguy67

Having now read the FSM in the HVAC Plumbing section I now know the 18 things I did wrong the other day. Luckily no injuries or fires resulted. I will be wearing appropriate PPE when I tackle the final repair job over the weekend.

Tallguy67

My A/C system is now back online. It was actually a really easy job. All it took was a $12 Schrader Valve Removal Tool, $200 Vacuum Pump + Gauges, $40 worth of R-134 equivalent and $0.75 Schrader Valve. It is nice and frosty in the cab now and the compressor doesn't cycle, it just runs.

sherod

Ok, bring your tools South. I have 2 r-12 systems to get going. I'll supply the beverage of your choice.

Glad you got it frosty again!