stokesey

AC was not cooling today, so I figured it's more than likely low on refrigerant. Not this time, I've got high pressure (80psi) on the low pressure line. According to Google that's caused by too much refrigerant or clogged condensor. I'm not a big AC guy so I figured I'd ask the forum. Thanks for any input.

thoiboi

Did you happen to fill up refrigerant on your own via one of those "DIY cans"? if so, too much refrigerant is probably right.. Unless there was a leak, you should never need to fill up refrigerant.. Additionally, if there was a leak, filling up would only be a stop gap as it would continue to leak out. Need more info so we can help further.

stokesey

Thanks for the reply. I filled the refrigerant DIY after my engine swap 5m ago. Pretty sure I didn't overfill as I used only one can. Haven't been paying attention to the functionality (maybe I didn't even test it?) as weather was cold.

Recent repair was alternator replacement. Think I got it clean, but I did disconnect and reconnect one small blue wire on the underside of the rad fan. Could be a loose contact there, but I haven't investigated because the access is so tight!

thoiboi

Do you have access to a set of manifold gauges to test both the high and low simultaneously? Like I mentioned, A/C is a closed loop so not usually something you need to "refill on" unless it leaked out.

If you're up for it, I recommend getting a set of gauges like these: https://www.harborfreight.com/ac-r13...set-60806.html to check the static pressure of your A/C system with the car on. You should be able to also rent it from your nearest parts store for free as well.

Then if you need to replace your condenser, you'd need to buy a vacuum pump like this: https://www.harborfreight.com/25-cfm...ump-61245.html

and then about 2 cans of refrigerant https://www.oreillyauto.com/detail/c.../r134a12v?pos=

Pull a vacuum on the system after installing the new condenser (make sure to get a new drier as well). Ensure that it holds the vacuum for the appropriate amount of time (i believe at least an hour) and then you can suck the refrigerant into the system and refill the system properly.

stokesey

Harbor Freight for the win! Their stuff is so cheap that it's almost worth buying the whole kit just to do a single job. Thanks for the breakdown , I will read and do some more diagnosis, and maybe dive in.

I did have high pressure on the low line once before on another car. I was able to bleed the gas a bit and then it somehow seemed to rebalance itself. Never really figured out what I did wrong or right but it worked. Most of my cars are older so they typically leak a little gas over the years. Probably from dry seals etc.