Hello, (1994 Ford 150 5.0L) I just had my ac checked, orfice tube replace, and everything vacuumed. The tech filled everything up with proper gauge readings on high side and low side. The compressor was purchased new 3 yrs back. The air does not get cold at idle. It only gets some what cold during driving and not that cold. It was all fine until three weeks ago my ac vacuum hose was leaking causing it to go to defrost and that was fixed. I hear about the fan clutch giving out, but my ac blows cool/not cold from a cold truck startup. Wouldn't the ac condensor be cool and blow air cold from a cold truck startup. Oh and the other thing...my ac compressor stays on...back in the day it would click on and off...Its hot here and texas so i need some help. The tech says its my compressor but i don't know. Why would i get some cold air during long drives? Maybe clogged condensor...Help me please

 

The fan clutch is dead and the system is undercharged, most likely. The bad clutch gave readings that indicated the proper pressures when it was actually undercharged.
Also, high pressure due to the failed fan clutch may have dislodged the orifice tube. System pressures will tell if that is the case.
If you have access to manifold gauge set, mist water from a garden hose over the condenser. If the clutch is dead, the high side pressure will drop like a stone.
A weak compressor is a possibility, but you need to know the pressures to tell for sure. Get the pressures and post them here.(Max AC, high blower, doors open, 1500 rpm) Post the pressures at idle also in this case.

 

Yeah...we did mist some water into radiator and condensor and pressures drop like crazy...the high side gauge needle was twitching back and forth and he said a bad compressor does that?? Why would it blow warm/not so cool air straight out of a cold startup? Wouldn't the ac condenser be cool? Does the fan clutch immidiately start working/cooling the condensor. Does the condensor get hot really quick? I don't believe my compressor is bad...it does get cold when driving or driving really fast(high rpm). But it drops quickly when i slow down or stop. The fan does spin when on...and i try and spin by hand and it has some play...same amount of play when truck cool and hot. Thanx for reply...fill me with more info please for i have no ac knowledge!

 

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"Yeah...we did mist some water into radiator and condensor and pressures drop like crazy...the high side gauge needle was twitching back and forth and he said a bad compressor does that?? "

Ding ding ding! We have a winner! Dead fan clutch. The twitching "can" be caused by a bad reed valve in the compressor, but it can also be caused by oil slugging, air in the system, refrigerant slugging, ....

"Why would it blow warm/not so cool air straight out of a cold startup"

No airflow over the condenser to cool the hot compressed gas coming from the compressor.

" Wouldn't the ac condenser be cool? Does the fan clutch immidiately start working/cooling the condensor. Does the condensor get hot really quick? "

The gas leaving the compressor is hot immediately due to being compressed. It needs to be condensed (gas to liquid) by cooling as it passes through the condenser. The condenser can't dissipate this heat without airflow. If the refrigerant isn't a liquid when it leaves the condenser, it can't spray into the evaporator as a liquid and boil back to a gas. This is needed to make the evaporator cold. That's the easiest that I can explain it.

"I don't believe my compressor is bad...it does get cold when driving or driving really fast(high rpm). But it drops quickly when i slow down or stop."

It's possible that the compressor is bad, but not likely. You need to replace the fan clutch first and check the pressures. Also make certain that your mechanic pulled a deep vacuum on the system before charging and replaced the accumulator.

"The fan does spin when on...and i try and spin by hand and it has some play...same amount of play when truck cool and hot."

This only tells you that "Yep, there's a fan clutch in there". There's no good way to test a fan clutch and it's ability to move the necessary amount of air. You may hear about for checking drag, etc. Such tests don't tell you anything useful. You can get fancy with a strobe tach (doesn't everybody have one? ). Basically, if a fan clutch is over ~8 years old, it's bad as far as the AC is concerned. Engines are pretty forgiving of a bad fan clutch, AC systems are not. Except for low refrigerant charge, it's the most common problem I see during the AC season. I've probably replaced the FC on 20 mid 90s Ford products this summer.

"Thanx for reply...fill me with more info please for i have no ac knowledge!"

Now you have a little bit. I hope it helps.
The only thing I can add is: If you are using R-134a in the system, get a Motorcraft fan clutch. They're pricy, but the aftermarket ones don't work well with a converted system. If you are still using R-12, aftermarket is ok.
You are using R-12 or E-134a, arent you? If your mechanic has installed anything else, get him away from your truck, pronto!

Good Luck. Post back and let us know what happens.

 

Got fan clutch today as you stated...Going to install later on today...will give update...Thanx a bunch!

 

oh and yes...134a...oh and this morning it rained...no sun has appeared and my ac is blowing cold...i'll give update in a while on install

 

I installed new fan clutch and it help out but still is kinda warm at idle. Went to tech and he put gauges back on with new fan clutch...pressures where about 53 on low side and high of 260. With the throttle engaged...low was about 31 with high steady at 260 any other ideas....On the high side gauge, the needle was twitching and he claims the compressor is bad. He says that if the needle vibrates, a valve is messed up in the compressor...but he's not sure...Air coming out of vents at idle were at 60degrees on max ac max speed. and 58degrees when little throttle engaged. When i drive around...my ac gets cold or at least comfortable for my standards...any ideas??

 

Overcharged.

High side should be around 2.5X ambient. You'd have had to have been ove 100F ambient to get that kind of high side reading.

steve

 

Yep, I agree with Steve. You're overcharged unless your ambient temp is about 115 degrees.... Or the orifice is plugged.
Your "tech" didn't diag things right and his mistakes are now going to cost you money. The recharge along with the bad fan clutch could have caused condenser plugging due to compressor failure.
The compressor has blown its reed valves. The pieces of the valves are now in the condenser and the orifice tube.
The only sticking point is; What caused the compressor damage in the first place? The bad fan clutch before the diag? Or the Techs' bad diagnosis and overcharge?
You mentioned that he replaced the orifice during the initial check. Why? Plugged? That indicates the compressor was shedding parts before he checked the system.
If there was junk in the orifice initially, he should have suspected the compressor and not gone any further. If he went further, you owe him nothing past that point for diagnosis. You own the bad compressor and subsequent damage, though.
If the old orifice was clean, he owes you a compressor and condenser due to overcharging the system. He should have noticed the high pressure caused by the bad fan clutch. He didn't stop there, and now the compressor is toast.
You're going to need : compressor, condenser, orifice, accumulator, system flush, some seals, evacuate, and recharge.
Talk to the Tech about splitting the cost. He F**ked up in his diagnosis, but the main cause was likely pre-existing. He just didn't diag it properly it seems.

 

Ok... mistake...high side pressures were 250 on idle and with throttle... I had him change the orfice and vacuum system just to have peace of mind and its a way of elimination. The orfice was clean just couple specs of metal shavings possible from old compressor that shattered on me 3 years ago. I have no clue...i just know that it stays cold when i cruise around and at idle it gets only cool...not cold. I'm gonna take to another tech and get another diagn test.

 

Let us know what you find out.