Questions on AC low pressure port and missing cap

I discovered that the cap on the low pressure port of my 2004 T&C van
was missing and wonder if this has caused any problems. Is its purpose
merely a dust cap (if so would any tight fitting cap suffice) or does
it have other purposes?

Next problem is where to find a replacement without being raped by the
dealer. Anyone know where I might locate one?

Frank

 

I would try a salvage yard. One from another year and/or model would
probably fit.

Everytime I have my A/C serviced, I always check for these before
leaving the shop. Very few take the time to put them back after the
work.

KM

 

Thanks for the response - will try a salvage yard. Still not sure if
the cap serves any other purpose than to keep moisture and dirt out of
the port.

Frank

 

as long as the actual valve is still in the center of the port. that's what
holds everything in . the cap works like a valve stem cap on your tire.
keeps dirt out etc.

 

Besides keeping dirt out it should have an o-ring in it and it's a
second seal to prevent freon from leaking out if the schreader valve
leaks a little. Usually if there is a leak you'll see oil. If you
run by an AC repair shop they may have a cap laying around they would
give you.

 

Thanks to Rob and Ashton for their input.

Frank