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GM Low Side Shrader Valve Leak.

Sellncars on Thu June 28, 2012 11:06 PM User is offline

Year: 1997
Make: GMC
Model: Sierra K1500
Engine Size: 350
Refrigerant Type: R134A
Country of Origin: United States

Hey everyone,

A new problem arrives. Last weekend or so i changed the A/C line and the Accumulator on my truck, vacuumed down the system, No leaks, went through the whole routine, posted new numbers and a vent temp, few people said numbers looked good for a truck. So, i added dye during the refilling process, the only place that i see dye is the low side port. I have cleaned the port and cap just to see if there was fresh dye, and there is. Start over with a new schrader valve and a refill again?

GM Tech on Fri June 29, 2012 6:20 AM User is offline

A new cap with the proper rubber sealing washer inside will seal that port.

The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

buickwagon on Fri June 29, 2012 9:12 AM User is offline

If you don't trust a plastic cap as a long-term solution (although one sealed my high side port for months) then look very very closely at the port itself. Some GM ports do not have a replaceable Schrader valve -- the entire port must be replaced and unscrews from the line. And yes, to go that route means you must recover the refrigerant first, change the fitting, vacuum the system then reinstall the refrigerant.

I've saved hundreds on service by spending thousands on tools.

mk378 on Fri June 29, 2012 10:54 AM User is offline

There's always dye around the service ports, it is hard to diagnose a leak that way. You should confirm leak or no leak with an electronic detector. Shrader valves almost always leak slowly with the cap off, which is of no concern if the cap is good.

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