Engine Size: 3.0 V6
Refrigerant Type: R12 to R134 Con
Ambient Temp: 90+
Pressure Low: 50
Pressure High: 300+
Country of Origin: United States
Well it that time of the year again. I haven't done a conversion from R12 to R134a in some time and this one has stumped me. My neighbor brought her fathers old car to my shop with a belt broken. I had to break the news that the reason was the A/C compressor locked up of course she said oh we don't use the A/C because it has a leak. I had the pleasure of explaining the workings of the compressor to her so she would understand what happen.
Ok I had to do a firewall forward A/C repair. All the hoses were swollen, the condenser had an oil spot on the right corner/middle section. I verified the condenser leaked with a Nitrogen pressure test.
Flushed out the Evap and did a nitrogen test on it and it passed.
After replacing all the hoses, compressor, condenser, adding 7oz of BVA Auto 100 oil, vacuuming down for an hour. I charged the system with about 80% charge (32oz) R134a.
I noticed right away the high pressure side was high, it will come down just under 300 once the car is cooled down but if you increase the throttle the high side will run away. The low side does come down to around 40 but the high side pressure triggers the cut out switch which is some where around 360 or 380.
The vent temp at best I can get is about 54 running down the highway and 65+ at idle.
Ideas suggestions? The new condenser is the updated narrower R134a style. The old condenser was very thick with double rows. There is a big gap now between the radiator and the condenser so could this be the problem not enough air flow? I have converted the same car several times but never had to replaced the condenser.
I have evacuated and recharged twice to make sure there was no air in the system. I have also done a nitrogen pressure test for leaks at 200psi system held fine.
I have not sprayed water on the condenser yet to see if the pressure drops nor have I put my temp gauge on the inlet and outlet pipes of evap. They feel close to the same temp but I will go put the temp gauge on them in a little bit.
Any help would be great since she is my neighbor and is very good to me I am not charging for labor and I need to move this car out so any help would be much appreciated.
Should be a large drop in temp between the inlet and outlet of the evap, Unless you meant the condenser? Is the condenser fan running with the ac on? Do you have the lines running right? I think they are different sizes, but don't have one in front of me...You will have to pull the O tube, make sure a plug didn't get blown into the condenser by accident, make sure air goes thru it unrestricted.. Just a few things to check..
Freedoms just another word for nothing left to lose
There temp difference between the EVAP inlet and outlet is 3 to 5 degrees. This is a ford so no getting lines crossed as everything is springlock and different sizes. The o-tube is one of those built into the line and its a new line. The o-tube is located at the condensor of the line on this model.
Fan is running with A/C on. As stated before the new condesonr is much skinner than the old r12 one. There is a large gab between the radiator and condensor and I can feel the fan pulling air thru it but very little.
I just got back from hooking up my fluke temp meter to the inlet and outlet as stated above there is a 3-5 degrees fluctuation difference. Its about 90 degrees outside right now. At idle the temp on the evap inlet/outlet was reading 41 and 45 once the car idle for a while and the inside cooled down
I sprayed a mist of water over the condenser and the pressure dropped quickly. I was able to put a large fan in front of the car and keep the pressure on the high side around 250 and when the engine rev up it did not climb to 300. Vent temps were in the low 50's high 40's via a pocket gauge since digital was hooked to evap.
So do I need a aux fan or is there a blockage somewhere? Should there be more of a difference between the inlet and out let pipes on the Evap? I am measuring right at the entrance/exit of the fire wall on EVAP.
Patiently waiting :-)
Thanks again for your help.
Edited: Wed June 11, 2008 at 9:03 PM by BigMike
Are you sure the condenser fan is turning in the right direction? Check the temps on the inlet and outlet of the condenser.
PS: If the O tube is at the condenser, then the difference between temps in the inlet and outlet of the evaporator should be close..Outlet slightly cooler..
Freedoms just another word for nothing left to lose
Edited: Wed June 11, 2008 at 9:38 PM by Chick
I was thinking about that as well. I will go back and see if I can still see the sticker that on the condenser that said R-134a only. I have played around with adding removing freon with recovery unit. But to me the compressor being at 300 and going up is to high for an FX compressor. The best I can get is is 35 low side 300 high side and 50 at the vents. Thanks your help keep the suggestions coming.
Edited: Wed June 11, 2008 at 10:27 PM by BigMike
Radiator fan pulling air from radiator.
condenser inlet 177
condenser outlet 130
about 40 degree difference
Is that a good enough difference of temp or not enough?
I have played around with removing/add refrigerant with Recovery unit until I got a pressure read of 30 -35 on low and high I could get 275. But when I drove down the road and accelerated hard or rev up the engine a little from idle high shot up to 300 and low side drop below 28 and cycle switch cut out and came back in around 45 on the low.
Any body got an idea on what the charge should be with this new condenser?
The vents temps at best were 48 to 50. Max and Fan speed high doors closed.
I just thought I would post an update incase someone runs across this thread in a search with the same issue.
The problem was fix by getting rid of the made in China Condenser made by a wheel know brand that I will never buy again after this ordeal.
The condenser was painted for one some may so that ok. Two it was not made out of alum. it was some light steel or other alloy. A magnet stuck to it and you could not even push or bend the fins on the condenser. Also what should of been a clue to me was the new updated condenser that is thinner than the old R12 style that came out of the car was heavier.
I called a local A/C remanufacturing company here in the Dallas area called Austin Baker who also sells anything auto A/C related. They already had encounter this issue and got me a condenser made in the USA and was on 20.00 more than the original one I bought from the local retail auto parts houses I have commercial accounts with. I also thru out the accumulator too as it was made in china and out of the same type of metal and got an ATCO one.
New made in USA Condenser even came with new updated mounting brackets and sticker. The sticker reads NOTICE this car has a updated condenser that is high efficiency and a smaller design. This condenser hold less refrigerant than the original OEM. Please use 2.4lbs of refrigerant when charging. There was a note in the package as well stating to stick sticker over oem refrigerant charge label.
High side now 225
Low side now 38
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