Model: Civic LX
Engine Size: 1.7L
Refrigerant Type: R134a
Ambient Temp: 100+
Pressure Low: 40
Pressure High: 135
Country of Origin: United States
I just joined the forum to read up and possibly get some help diagnosing my vehicle. Trying to get my car back to blowing cold air has been a hassle for me. I read up alot of stuff and had a friend help me but I can't get it quite right. need to get this fixed so my son won't be burning up in his seat in the back seat. That and between doing all the other mommy chores.
So I had a friend help me and he replaced my expansion valve and the Dryer ( ? ).....We rented a vacuum machine and pulled vacuum on the system for a good 2 hours. The vacuum held overnight so it is sealed up pretty good.
Added 2oz of PAG46 and charged it the next day ( 19oz ) and it was blowing about 38 degree air. I thought all was good. I made him a nice dinner to show my appreciation. The next day the car would only cool down when it was physically moving more than 50MPH on the highway.
He came out to check it and said the low side ( ? ) service port valve was leaking. So he bought new high and low side service port valves and installed them. Re vacuumed and recharged the system. This time it lasted for about 2 days and same thing happened as the first time. We checked the low side service port again. Filled the port with a tiny bit of water and you can see an air bubble come up once every 5 seconds or so.
Is there any trick to getting that sealed up? or did we just get a bad new service port valve?
I appreicate anyones help.
Sometimes service valves leak slowly no matter what you do. The plastic cap should hold the gas in (you do have plastic caps on them, with good gaskets?). Probably there is a leak somewhere else.
Be careful not to get water into your system. Clear all the water out of the port before connecting a gauge hose.
Edited: Mon August 24, 2009 at 11:27 AM by mk378
Shouldnt the vacuum detect if there is a leak if it doesnt hold? and yes......i do have caps on the ports.
My friend explained the whole a/c theory to me...I understood some of it. He used comrpessed air to blow the service port water out before he did anything else.
Its been about a month now and like I said.....the a/c works great once im at highway speeds ( 40 degree ) Just that in town it doesnt cool very much. Maybe 65 degree air.
are you sure your fans are operating properly? the high side pressure looks a bit low for that ambient....at 100 degrees, should be closer to 200psi, so you might be just a bit low also..
Freedoms just another word for nothing left to lose
Yes chick. Both fans turn on. The compressor turns on when the a/c button is turne don but it is always on. It never turns off or cycles on and off.
I didn't see the pressures at first, I agree with Chick it's undercharged at the moment. O-rings and compressor shaft seals can get so they hold vacuum but leak under pressure. A "sniffer" (electronic leak detector) is very useful to find these larger leaks.
OR, since there is a consensus that the system is a bit low, top it off with refrigerant that has leak detecting dye.
When we recharged the system we added a 12 oz can of 134A with UV leak detector and another 7 oz of regular 134a. We sniff tested the connections and checked with a UV light. No leaks anywhere except from the low side service port. There was UV stuff inside there and when you take off the cap you get a "PFFFFFT" noise....
I am having my friend replace the service port valve again with a new one and see if we just got a bad one last time and do a recharge.
There could be a leak in the evaporator box, it can be hard to see those with dye. Look in the end of the drain hose with the UV light. Also you can run it until water is dripping out of the hose, let the water drip onto a paper towel then inspect the towel with the UV light for signs of dye.
Hey guys. More info on my dilema here. I took the car to a shop that does a free a/c check. They told me they couldnt detect any leaks , that the r134 level was fine and that they didnt know why its acting up. To diagnose any further it was going to be $75 bucks.
I brought it home and we hooked up a set of mastercool gages to it. Here are some of the readings which I find very odd. Can someone please help me out?
Ambient Temp = 95
idle rpm =725
low = 45
high = 120
low = 27
high = 140
high = 145
The only way to know with certainty that a system is properly charged, is to remove all the refrigerant and weigh it back in. Did they do that?
The most obvious explanation for your pressures is an undercharge. If you don't know the charge level, try adding some and see if you can get the high side up to around 220 (in 95 degree weather). It should not take much more than one can to do that. See if it cools any better. Of course if it keeps coming up undercharged, there must be a leak.
Here is what we did. We replaced the service valves again. You can tell the low side one was leaking bad. When we took off the cap we heard the " pfffft" noise of it being under pressure.
Pulled vacuum for 1 hour. Let it sit one hour. The vacuum held. The specs on the car call for a max of 19.4oz
We added 1 can of R134A. The can weighed 15.3oz before we tapped it. Empty is weighs 3.34oz so that means we added a total of 11.96oz with the first can.
The second can weighed 17.89oz before tapping it with the tap on the can. So I added another 7.5 oz to the system until the second can weighed approx 10oz on the scale. I added just a tad bit more to account for loss in the lines and what not.
So now I have the factory spec amount of refridgerant in the lines. The car cools down to about 42 degrees sitting and about 38-39 on the highway.
My pressures were
98 ambient temp
150 high ( still seems kinda low )
Hopefully it works out ok. If not I dont know what to do.
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