at the end of last summer my 93's ac started to go out. It wasnt a big deal cuz it was getting cold but now that its starting to warm back up i need to get it fixed.
With the both Normal AC and Max AC with the fan on high the compressor cylce's on and off every 5 seconds. Befor i had always heard it cycle for much longer periods.
Also i checked the freon pressure with the little tire guage style guages and the low side reads 30 psi and the high side reads 80psi. The high side piping befor the evaporator is a warm, after the evaporater its kinda a little warm, and after expansion orfice it cool. And the air blowing with the setting on vent is cooler then the normal AC setting.
My questions are, is the frequent cycling casued by the low freon or is the low freon pressure caused by it cycling so much?
And also, im going to be converting to 134a, i'v done some searchs on hear and learned that you have to replace the dryer as well as putting oil into the system, is this correct? and do yall know of any good kits?
I'v worked in home HVAC but never in auto so there are some things im unsure about.
Sorry for the long post, i know that all these things are important in a ac system.
Compressor short-cycling is usually due to a low refrigerant charge. If those readings are to be trusted, they confirm this.
Steve
Yep, projectSHO89 is right on the money. Most likely a leak at one of the Spring Lock fittings in the refigerant loop.
Being a 93, don't just grab a can of refrigerant and go a'charging. Your truck is likely an R-134a system, but there were a few R-12 systems early in production for 1993. The cutoff was in September 1992 IIRC. What is the build date on the door tag?
As for the leak, if you see a fitting in the AC lines with oily dirt on it, that's probably the main culprit. It's usually one of the condenser (front radiator) fittings or the smaller line sticking up in the right rear of the engine compartment (evaporator inlet). Look at the front of the compressor for oily, dirty residue. If the clutch is grimy, there's probably a leak.
Regardless, the AC system is due for a proper service after 15 years. You need to: have the existing refrigerant recovered, have all of the line fitting seals replaced, flush the old oil out, a new orifice tube, a new accumulator, the system evacuated, the proper amount of oil added and the system recharged.
AC systems don't usually require "maintenence" until they stop working. Once they "break", the above steps are required to assure that they perform reliably for the next XX years or until you sell the truck. Shortcuts usually mean disappointment within a short time and money wasted. (ie: another leak, compressor failure, etc).
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Shortcuts usually mean disappointment within a short time and money wasted. (ie: another leak, compressor failure, etc).
yep, that's what i'll be going through next month....already had them replace a few parts..."oh it's not the compressor"...but in the end, it probably is.
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Thanks, checked my door tag and it says 05/93, does that mean its r-134a. I thought that r-134a wasnt used until the late 90's. but i could easily be wrong.
I checked all the fitting and they are surprising for a 15 y/o truck. The clutch looked clean, but a tiny bit of dusty grease. Im not totally sure if it freon, or because its right above the p/s pump which does have a leak and is covered in grease, so it could be from that. and its right out side the fan, so anything could easily be blown on it.
Does anyone have an idea of what the proper service would cost? Is it something that can be done by me? iv have access to a vac pump and a bottle of r-134a and gauges.
R-12 fittings resemble tire valves, R-134 fittigns are quick-disconnect, similar in appearance to what is used on air tools.
As far as the cost of service, you'll need to get out the yellow pages and call around. Cost of any service will vary based on the type of service to be performed and on the level of quality you will likely get.
Steve
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Im gonna have to chang to the newer r-134a, can i do the service when i do that? I know its not as easy as just charging it with r-134a, and it would be best to get it done by a shop, but i dont have the money to do that, and i always seem to have free time which is often used making uneccesary modifacations to the truck.
i guess ill do some searching as to what all has to be done in the switch.
As for the leak, do ya'll think that theres a good chance that its the compressor?
thanks for the help!!!
Any other ideas or thoughts are welcomed
Ya, i had heard that, but after alot of research i found that if you do the conversion right and not the cheap way, it shouldnt even be noticeable, it might even be colder.
r134a will not be as cold as a vehicle with r12. especially older vehicles with small condensers
Actually, that truck will convert quite well. It was mostly set up for R-134a to start with.
On that truck, the only real difference for R-134a is that you need to use the Ford Blue orifice tube and adjust the cycling switch about 1/4 turn to drop the low side pressure down a few psi. You will need ti use an Ester based oil. All of the things that I mentioned earlier apply. Don't take any shortcuts. You're in a high temp zone so the the AC needs to be as close to 100% as possible.
You will also want to replace the fan clutch with a new Motorcraft unit. At 15 years, it's dead as far as the AC is concerned. Don't use an aftermarket fan clutch if you go with R-134a!! The cooling WILL drop off at low speeds and idle.
Stay away from the cheap aluminum adapter fittings. Get steel fittings from NAPA or a real parts store. Don't use any additives,sealers, boosters, etc, only virgin refrigerant.
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Thanks lsrx, on the subject of a fan,i will replace the clutch like you suggested, but would it be worth while putting an electric fan infront of the condenser? I do idle for long periods sometimes, and im sure it would help with that, but how do electric fans do in city driving? And up to what speed does it help, i know that once you get going air is just forced through.
Im planning on fixing it this weekend. luckily we've had several cold fronts come through and it hasn't gotten as hot yet, but its still coming.
Hey eveyone. Sorry its taken me so long to get back to yall. I figured i'd let ya'll know what been going on. Last weekend was when i was planning on working of the A/C but ended up having to work on the clutch. The pedal got messed up.
Anyways i went yesterday to get the parts, i ended up getting the compressor and red orifice. The Receiver dryer will be here Monday and after talking to the parts i went home to pull the orifice to see if the system was contaminated, it was, i pulled out several large (1 in by 1/4 in wide) pieces of black Teflon. So ill be replacing the hoses and the evaporator as well.
OK, i have gotten all the parts needed, and i have started to replace them. The first thing i did was to pull all the old stuff off. Then i went ahead an put the new compressor on, i didnt hook up the clutch switch so the new compressor wont cycle without the freon.
But heres my question. Im need to put oil into the system, the instructions that came with the new compressor "which is a motorcraft" said to add 1 or 2 oz more then you drained from the old compressor. But my old compressor didnt have any oil in it, or at least i wasn't able to get any out.
How much oil do i need to put in? and where is the best place to add it? And what i the best kind of oil to use?
Got it fixed and running. Does great so far. blows 40* at 70* out side temp at idle. I hope that it will keep doing well. We ended up charging it to 175 on the high side, but i might add a little more in the near future once we see how it does.
mine did that, was undercharged. i did a conversion on a wifes 70 mustang, everything 134. i only kept the evaporator under the dash. i went with a aluminum sepertine condenser, all new barrier 134 hoses, new dryer, and a new sanden 134 compressor. im in az with temps of 110-120. works great. i did the cheap conversion to 134 and it worked half way for a couple years. the temps and pressure of the 134 are to high for the r12 system. like i said you can make it work but you will be messing with it a lot. they make all the r134 pieces for the older cars and its a direct bolt in replacement. it would be nice for some one to make a r134 complete conversion for the r12 ford trucks.
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