Air Conditioning blocked line??

[rick]

Hot days are here and so I plugged in my air conditioning compressor (left unplugged and therefore not loading the engine during Fall and Spring months).....and then flipped the dial to air conditioning. After a few moments the the compressor kicked in and the air began blowing out of the air conditioning vents in the centre console (the flip-down 1961 unit). But no cool air.

Local garage assumed some of the 134A had leaked out over the winter and tried to pump in some more..... but couldn't. The system is holding pressure fine. Their diagnosis is a blocked line somewhere and they didn't have time to try and locate the problem. Booking an appointment with them is a minimum two weeks wait.

First of all, any ideas what's going on?

Secondly, should I take it to another garage that specialized in air conditioning ... or just wait out the two weeks for my regular guys?

Thanks, Rick

[action]

Can you install gauges?

If not then take to a shop. WE can speculate about what is happening inside it is kind of pointless because it is a guess and a AC gauge takes out the guessing.

If it is a blocked line you have some serious issues. The only reason an AC line would be blocked would be because of debris. Debris typically comes from metal shed off of the compressor. Which would mean major compressor repairs or replacement PLUS flushing the system to remove the debris. The other issue would be a receiver/dryer that came apart. Kind of rare but does happen. Again a system flus is needed.

However more likely that shop has mis-diagnosed the system. And gauge readings will confirm or diagnose the system. Without that, it is a parts replacement guessing event. If you have that kind of cash to burn.

Action

[rick]

Okay, Action.

So, from what you are indicating, the Service Tech's will be able to get a read-out from their instruments as to what the issue probably is. Thats good news. I'm in no hurry, I'll wait the two weeks for the appointment.

Thanks!

Rick

[action]

As long as the instrument is a AC gauge set


Action

[George W]

Are you saying that on your '61 the a/c compressor clutch is always engaged ? That sounds odd. Normally the clutch just freewheels unless the a/c is turned on. Gauge readings will tell right away if you have a blockage. The only "normal" blockage in the system is the restriction that's built into the expansion valve but that would never be totally closed.

[TonyC]

Well, this question should be in the "Electrical and Accessories" category, but...

I agree, you need to have the system examined with proper A/C gauges before deciding on what action to take. If the gauge inspection suggests debris, then that will be involved. Rick, you mentioned R-134a, which tells me your A/C has undergone mods. My question is, how much modding was done? In the original high-pressure line of the factory system, there was a fitting which held a metering valve, meant to regulate how much freon would pass through (at least that was the case with cars later in the decade). That valve had a bad habit of seizing up over time, either with rust or debris, causing blockage and even leakage from blow-outs. An old mechanic who was actually my mentor into automotive mechanics told me that valve was a redundant piece which was not actually necessary for normal operation, and should be discarded. If your lines were all replaced with new lines during the modding, then it's likely that valve no longer exists and is no concern. However, if you have the original lines, it could be a concern.

On my car, that valve is located near the sight glass in the high-pressure line, along the inside of the driver's fender. I'm not sure if it would be in the same place on your year, but I would check that if the gauge test suggests blockage somewhere. Again, I stress that this applies only if you still have the original factory freon lines in place; if they were replaced with new lines, I doubt that metering valve will exist to cause trouble now. Another possible place for blockage would be the expansion valve, which should be at your evaporator core.

But first thing to do is determine whether there is in fact blockage somewhere, and a gauge inspection should determine that. Have that done first.

---Tony

[frasern]

How long ago was the 134 conversion done? Is your appointment with the same shop? If not, maybe give them a call and see what they think.

[rick]

Hi Fraser, Yes my appointment is now with the shop that did the conversion. I zipped the car over to another nearby shop to have them check to see if my R-134a had leaked out over the winter, but I have very little faith in them. The original shop are going to be looking at it on June 4th. Meanwhile, it's an ok car to drive around with the windows down. Just the right amount of air gets in plus it's just at the right height to have my elbow stuck out the open window. Cruised around for an hour last night around 9pm.

Thanks for that info Tony, I know for a fact they didn't replace any of the original lines and so will alert them to that metering valve. The sight glass in my '61 is on the passenger side of the firewall.

Good point George, not sure why they unplugged the compressor in cool weather. I'll ask them.

Cheers, all

Rick

[frasern]

Hopefully the "dog days" will hold off until after the fourth.
My '62 Buick has air which has needed a recharge for over 30 years now, I just never use A/C anyway, so haven't bothered. It is a 2 dr. hdtp, which is designed to be driven with the windows down, and an elbow out the window! Most newer cars, with fixed rear windows, are so noisy, you can't drive them that way, at least not on the hiway. Your car, with it's windows down, should be comfortable on most days, plus you can hear the compliments!

Edit; Let us know what they find, I would be curious to know if it's an "old rubber" problem.