A/C fittings reversed?

[cory58]

With summer approaching, it's time to get the A/C in my Touring working again. Thought I'd check the fittings and see if the system's been converted to r134a. My understanding is that the low pressure schrader is in front of the shock tower, and the high pressure schrader is on the inner fender.

Here is what I found.









Are these fittings reversed? Shouldn't the larger one be on the high pressure line? The blue cap is marked with an "L", which I always thought meant low pressure.

Thanks, Cory

[jeffnhiscars]

The low pressure is by the shock tower and is typically blue. Iirc all the fittings have different threads so you shouldn't be able to switch them around. I cant explain what's in your pics but I'd be pretty surprised if it was anything but standard.

I'd put manifold gauges on and if you system it's empty, pull a vac then do a static charge (meaning with the engine off). That will give you enough pressure to close the LP cut out and let you start the car. Once you do that you'll know pretty quickly which line is which.

[Das Delfin]

^ agreed. OP I think your plastic caps are just switched around. Get some gauges and see if they fit the way they are supposed to (blue near the shock tower, red on the fender)

[cory58]

Thanks for the responses (and thanks Jeff for the PM)! It's not easy to see in the pics, but the fitting on the shock tower is noticeably larger than the fitting under the fender lip. My R134a recharge hose also popped right on to the fitting under the fender lip. These are the things that make me think the fittings are switched. Does that make sense, or am I confused on something?

I am trying to track down a set of gauges, so I can test the pressures and try to add some refrigerant in what should be the low pressure line.

[Das Delfin]

usually the top off kits come with the blue fitting, the low side (the one that's supposed to be near your shock tower).

Does your A/C work? Try taking off the adapters and see what's underneath. There is a shraeder valve that keeps freon from escaping

[bmwstudent]

They look like 134 retro fit caps on regular r12 lines. In which case they could be reversed because r12 ports were the same size on high and low side. Either way, the low side will have the larger diameter pipes. High side will have smaller diameter pipes. If the caps are on the wrong sides just unscrew them and put them on the correct ports. There should be Schrader valves in the line under those adapter caps. Remember, all these cars came originally with r12. Red cap=small diameter pipe=high side: Blue cap=larger diameter pipes=low side. Suction is always larger than high side in any type of pumping system.

[jeffnhiscars]

Autozone (or Advance) has manifold,gauges in their free rental program.

[cory58]

Try taking off the adapters and see what's underneath. There is a shraeder valve that keeps freon from escaping

Thanks for all the additional responses. I just assumed the schrader valves were mounted in the fittings. Great info to know that I can just switch the fittings without opening up the system!

Cory

[Das Delfin]

right, the r134a fittings are just adapters. The actual valve is in the original fitting