93 Ford Explorer

I've refurbished the a/c system...taken apart, flushed hoses & condenser & evaporator, new oil, new seals, new accumulator, new orifice tube filter. Reassembled & had the system vacuumed at local shop, held the vacuum, appears to have no leaks.

Bought 22oz can of r134a, and the system only took about half the can (or less) before the cheap little pressure gauge said, according to ambient temperature, that it's full (actually - over full at ambient 75 degrees/humid - gauge is reading 55psi). But according to my calculation, it should have taken 23.12 oz of r134a. (1.7lbs of r12 x 16oz/lb x 85% = 23.12). Compressor is running.

And the air flow is only slightly cooler than it is with the air off - that is not much cooling - though going down the road it *almost* felt a little cool.

Any ideas?

 

You need a proper manifold gauge set for diagnosis. Obviously, the single cheap gauge on the can isn't providing complete information if, for example, you have a weak compressor.

 

Well, a vacuum pump & set of gauges/hoses will cost me about $400-500 might as well not be trying to DIY. Is that really the only solution?

 

You might as well hand a set of 3-D glasses to a one-eyed man, buy him a ticket to a 3-D movie, and tell him to enjoy the show.

That's what you're doing.

A set of gauges is $75. You do the math as to whether a diagnostic tool is worth it to you.

 

I could just buy new compressor & go through the process again ($169 + tax for the compressor, another $20 to vacuum the system again) and then might just find out that the offsite vacuum, bring home to fill with rinky-dink can/guage set-up is also causing problems.

 

Do whatever you want.... It's your time and money to waste. You've already demonstrated that you cannot diagnose the fault with what you have.

 

Well, my post last night in the other thread turned out to be prophetic. Not that I'm a great seer or anything like that, it's just that that method is prone to problems that the do it all together method doesn't have.

It's shooting in the dark without a gauge set on it.

That said, did you purge the air out of the can's charge hose before connecting it to the low-side port?

Did you heat the can in very warm/hot water as you added it? As refrigerant leaves the can, that allows more liquid refrigerant in the can to vaporize, which absorbs heat. The can gets colder. Colder temperature in the can reduces the pressure in the can, and less liquid will change to gas. An equilibrium point can be reached where no more gas will go into the system, as the pressure in the can is not enough, even though there is plenty of (liquid) refrigerant remaining.

 

No Torky - I didn't get the msg to purge the air out of the tube first, until after I had done it. That being said, the tube is so short it (about 14 inch) that it couldn't have had much air in it - and I couldn't put it in hot water either because it was so short (could have preheated it though). But the can not having enough pressure to empty wasn't the problem- I could have kept putting more in from the can. The problem is that the system reached max low-side pressure, and only (guessing) about half the can had been put in the system. And no cooling at all (revised assessment).

That having been said, I haven't given up, just thinking on it a day or two, still trying to find access to a vacuum pump & gauges to have here in my hands where I can actually work instead of running to the shop up the street and keep shelling out $20 everytime I need a vacuum.

 

Maybe I'll just buy, use & sell for $220?

Also, I was wondering what this doo-hickey 3 inch cylinder is. It's in the photo here, on the right side on the high pressure line between the compressor and the high-side quick connect.

 

You can get a gauge set from Harbor Freight or Amazon. They are handy to have. I did the same thing you are doing when I had my 92 explorer a number of years ago and still have the cheap gauge set. The cheap one works for me considering how often I actually use it.

 

A muffler. In general, any line that has a muffler can not be (reliably) cleaned. In the case of a compressor failure, a line that has a muffler in it must be replaced.

I've lost track, and you have had multiple threads - You are converting a '93 Explorer from R-12 to R-134a, but what was the history of the A/C before you started working on it? I don't think you ever gave the operational status of it.

 

Sorry about the multiple threads, thought maybe that was better for individual questions, but now realize that was dumb, so I'm sticking with this thread now.

93 Ford Explorer - 248,000 miles & no sign of drive-train trouble.

The operational status of A/C was this: Not working - but compressor would come on when low-pressure cut-off switch was jumpered. Thought I was doing a conversion, but as I started the work, I noticed that the low-pressure quick connect was same as in conversion kit, and O-rings were already green, so system had already been converted. But some O-rings were damaged, and threaded connection to accumulator was able to be unscrewed by hand so it wasn't even tight.

I disconnected all lines, and flushed with a/c flush (actually, first time I flushed I hadn't found the orifice tube filter and flush/compressed air didn't move freely through one line, so once found and that joint taken apart, I flushed again because the orifice tube was so clogged with a gray pasty substance that I couldn't even recognize the long end of the filter without scraping the gray paste off with my finger - did that to verify that the new one was an exact replacement. Used compressed air to blow out flush from lines & coils - compressed air moved freely after 2nd flushing. Let sit an hour in the heat to evap more flush. Replaced orifice tube filter.

Removed accumulator (before flushing) - it had about 1.5oz of oil in it. removed compressor (before flushing) - it had another 1oz of oil in it. Drained compressor thoroughly, added 2oz of ester oil to it, turned it by hand a few times & drained again. Added 3oz of ester oil to compressor, turned by hand a few times, then reinstalled. Installed new accumulator, added 1oz of oil to accumulator (as per advice I found here on FTE). I had looked up the oil requirement of the compressor/system and it was 5oz - but compressor itself wouldn't hold more than 3oz.

Replaced all O-rings (except one of two - first connection after condenser coils - only had one new O-ring the right size - was an extra with the accumulator - reused one of the O-rings already there that wasn't damaged). Each O-ring was lubed with ester oil as it was installed.

Reconnected all lines, took to shop had vacuum pulled for 3 15 min cycles (45 mins), checked for 5 mins that vacuum held. Brought home (1 mile) and began to fill according to directions on 22oz can (has some oil in it - worried I might end up with more than 5 oz, but as it turned out - I could only get ~1/2 the can in before the low-side pressure reached 55psi, so I had to stop before the pressure got too high.

Compressor runs, but doesn't cool. Two days later, low-side pressure is still 55psi with system running. Still not cooling.

BTW, replacing the blower motor resistor, as blower was only running on high. That part is expected to arrive today.

I'm having trouble just bailing on this project, and am determined to finish it. I love my Explorer, but I'm burning up in the Alabama heat & humidity.

I've got this crazy idea I can buy the $250 vacuum pump/hose/guage setup, complete this project, then sell it for $220 on Craigslist or something. I'm willing to buy new/refurb compressor ($169.00) I think you're also suggesting I need to replace the line with the muffler on it (even though it's not clogged?) I haven't looked up the cost of that - but it's the largest, most complicated line in the system.

I appreciate your help, advice, & patience.

 

That hose is $63 + tax

 

I would put a gauge set on what you have now, and see what it all looks like. And then determine a course of action from there. May sweat a few gallons before it's all done

About the muffler, since you did not have a compressor failure, one could make the point that if your flush solvent was all evaporated out of the muffler, then it may be okay. But another way to look at it, is, if those hoses are the original 1993 vintage hoses, they are pretty old, and solvent has been run through them that may have weakened their internal walls further.

I did a total A/C system replacement on my '94 after a compressor failure, a firewall-forward replacement. Everything refrigerant touches I replaced, so I had all-new rubber hoses too. My hose assembly on the compressor had/has a muffler too. Due to the type of failure mine had, and the age of the rubber, I did a total replacement.

If you get the new hose assembly, it's possible that the mechanical routing of the hose(s) may be a bit different. On my '94 Bronco, the discharge hose from compressor to condensor used to run under both plastic ducts in and out of the air filter box. With the new hose assembly on that side, I had to run the hose between the two air ducts, and had to bend tubing a bit here and there to get everything to fit correctly. On the condensor to evaporator liquid line, I had to do a LOT of tubing bending, to get it to fit right, and I wanted that tube to come in perfectly end-on to the evaporator inlet where the orifice tube is, as that connection was the only spring-lock coupling on the whole truck for A/C. The less stress on a spring-lock coupling, the straighter it is, the more likely the two O-rings inside will stay sealed over many years.

Almost all A/C parts are being made in China. Fit is "approximate". It's working great, though. I had stopped using my '94 in the summer other than very early morning, due to the awful heat. It's nice to have A/C back again!

One of the other users here mentioned a vac pump at Harbor Freight, I looked it up, $89 and says it can pump down to 70 microns. It looks a lot like some other vac pumps that are sold under different names for more $$. I can't vouch for it myself since I don't have it.

 

OK. if I can find the $, I'm going to get the vacuum pump/gauge/hose setup and will get back with you on the readings, before ordering any more parts. Thanks again!