So my A/C on my '97 Silverado v8 5.7 wasn't working. Nothing at first. Added some r134, then the compressor kicked on - sporadically at first, then continuously. Noticed a light bubbling/hissing from the high side service valve. Put the plastic cap on it hoping it would seal it. A/C worked for a day or two. Next time I drove the truck, a few days later, no A/C again. So my plan is:
1. Put some dyed refrigerant in and see if I can find another leak somewhere.
2. Either replace the service valve, or port, or whatever you call it.
3. Replace the cap, preferably with a brass one and some teflon tape.
4. Refill with refrigerant assuming I found no other leaks in step 1.

Sound like a reasonable plan? Anybody else have a similar experience.
Thanks much.

DD

 

the schrader valve should seal all on its own, the cap is there to only protect the valve from getting debris in it... using tape to seal the cap should not be needed.
Try snugging the valve down a bit and adding dye.. if no joy then the valve may need to be replaced....

 

Here is a link I posted a while back give it a read and see if it helps any

https://chevroletforum.com/forum/sho...t=conditioning

 

Thanks, in2pro. I'll check it out. I'm told this high side isn't a schrader, but is more like a ball valve. I don't see nuthin' sticking up like a schrader, but I'll prolly end up replacing it. They Chevy parts guy said these go bad a lot.

 

I found some brass caps that have an O-ring to seal the service ports. I am sure some service tech will say to replace the valves. $100 to $500 but I prefer to just eliminate the problem at a cost less than $20. I will never have to do this again.

 

The high side port went bad on my truck. I bought one at Autozone for 2.99 and replaced it myself. You do lose all the freon. The A/C has been ice cold for several months now. You will need a vacuum pump to do it yourself.