AC Black Death on 98 5.0 Please Help!!!

[Fiberford]

Not want I expected

This weekend I replaced the compressor, accumulator, and orifice tube. Took me about 2.5 hours. There was no black gunk on the orifice tube, which means the compressor was not totally gone. Just the normal metal shavings on the screen, and not a whole lot.

Now, I still have problems. The air is not ice cold, just enough to "cool" the car. A co-worker has a 96, and his is way better on the original compressor. I also notice that the air will be cool, then go warm, and eventually cool. Seems like it works better in idle, and rather crappy on the highway.

What the heck could this be? I'm wondering about any interior sensors. For a brand new compressor, this AC should be a lot cooler. Low side pressure when operating is 44 lbs. I don't have a gauge for the high side. Again, there was no black found anywhere, just neon green oil.

 

[Glacier991]

A couple questions. How long did you run the vacuum pump before the recharge? Did you flush anything? How much 134 did you put in ?.... 44 lbs low side at what outside temps? What are your vent temps? 44 is a little high....

 

[Fiberford]

I didn't run the vacuum. I just flushed the condensor, nothing bad looking came out. Reading 44psi on the low side with the system running, compressor running with outside temp in mid to high 80's. Both accumulator tubes are cold, one's a little colder. Noticed they weren't sweating with old compressor, but definitely sweating with the new one.

Part of me is wondering if the blend door is not functioning. I can remember a few months ago that the heat was not working. I hit the max AC button, then hit heat, and the heat would work. With 110k I'm sure the compressor was shot. My mechanic's diagnosis of black death....nothing black in the orifice. I'm game for whatever you suggest. Although I can live with it now, I'd rather get this fixed totally.

 

[Glacier991]

You have to pull a vacuum on the system prior to recharge. Have you read the the thread "Recharging your A/C A-Z ?" You missed a critical step. Also recheck the amount of R134 you added. May pay you to just take it to an AC shop and ask them to recover the charge, properly pull a vacuum (people confuse this with vacuuming.... it's NOT) and then recharge it....

 

[Fiberford]

That could explain things. What does pulling a vacuum do to the system that can make such a big difference?

As far as having a shop do this, I agree.

 

[Fiberford]

Glacier991,

Well, I don't think I need to visit a shop. I found a post were someone had problems with the automatic controls on his 97, 98, or 99. Anyways, someone told him to look at the in-cabin sensor, on the passenger side mini-vent. Well, while I was waiting for you to explain the need for vacuum, I walked out to the parking lot at work with a bottle of alcohol and q-tips from the first aid box. Cleaned off a bunch of dust, cranked her up, and wouldn't you know, ice cold air on both max and auto.

Glacier991, I owe you at least a lunch for all your replies. In fact, this site and its members owe you for all the help you have given on AC systems. You seem to appear with help on nearly every AC post, and I know at least I appreciate your insight.

Perhaps I didn't need the new compressor, but now I will never need a new one. The biggest lesson learned was never to go back to my mechanic that diagnosed Black Death.

For anyone with AC problems, I'd suggest taking two minutes and cleaning the sensor. Sure wish I had started there, and its free.

 

[Bruce Rock]

What does pulling a vacuum do to the system that can make such a big difference?

Two things I can think of:

1) It removes water by causing it to boil at a lower temperature (the reverse of your Mom's pressure cooker). You want the water out for two reasons I can think of: a) Water doesn't lubricate as well as oil. b) Water becomes a solid at 32 degrees F. It will block the orfice tube.

2) You have to get to a MIGHTY low temperature to condense air (turn it into a liquid). Lower than what you can expect your system to produce. If you have non-condesables your pressures will increase. Look for your new compressor to upchuck.

Better do what Glaicer says.

Visit your local library to get a book on the basics of air conditioning and continue to ask questions if you don't understand.

 

[Fiberford]

Thank you for the info on the vacuum. I don't want to drop another $300 on a compressor. The truck will visit a local AC guy this week. At least now I have ice cold air after cleaning the damn in cabin sensor. Its always the little things that get you.

 

[Fiberford]

Precision Auto/Tune is performing an evac, vacuum, and refill today for $70. The mechanic that wanted $1100 to fix my non-existant Black Death wanted $103. Thanks again for all of those who assisted me with posts on this situation. I hope I can return the favor. I've learned alot about AC's.

 

[Glacier991]

Bruce is dead bang on. Also air can eventually lead to acid formation. The main reason to evacuate is for moisture and non-condensibles. You'll be colder too.

 

[Fiberford]

I took it in last night, had the system evacuated, vacuumed, and filled. Also had them add dye, just in case. Turns out there was a fair amount of air in the system. The mechanic that evacuated the system said everything looked up to snuff on the install work. Air is working well, and I hope it stays that way.

 

[Fiberford]

This AC is driving me nuts. I've replaced the compressor with a new one, replaced the accumulator, replaced the orifice tube. Had a vacuum pulled, dye added, and refilled. Now the thing doesn't want to work when the engine is over 2100 RPM. With the engine warm and in neutral, I can run it to 2100 and it clicks off. This is really bad for highway driving. Any ideas? I'm almost ready to pay the dealer at this point.

 

[Glacier991]

Well one of several things could casue this condition. Either the high or low pressure cutouts are cutting power to the AC clutch, or the Wide Open Throttle (WOT) module is kicking in inappropriately. You'd have a clearer idea if you were watching pressures on high and low side when it happens.

 

[Fiberford]

OK. I'm going to buy a high side gauge and check this out. I'll post the readings tomorrow. I've noticed that as soon as the car hits 4th gear on acceleration and drops to 1500 RPM, the air gets cold again. Never a problem in idle or park.

 

[Bruce Rock]

OK. I'm going to buy a high side gauge and check this out. I'll post the readings tomorrow. I've noticed that as soon as the car hits 4th gear on acceleration and drops to 1500 RPM, the air gets cold again. Never a problem in idle or park.

Why not buy a manifold with high and low pressure gauges? Harbor freight has one for under $50.00 I had to have them replace one of the quick disconnects because it leaked but they did it under warrantee. Ebay may also have some. In the future, if you decide to get a vacuum pump, you will be set up. Or, can you rent or borrow one?

 

[Fiberford]

Thanks for heads up. I decided to check my blend door actuator. Its not working. I'm buying a new one from Ford tomorrow morning. Hope this is the end of my ac repairs for awhile. The gods of backyard mechanics must be shining on me, because I'd hate to think about replacing the blend door. I even went to Sears and bought a drill bit thinking I'd have to Jimmy rig the blend door like everyone else.

 

[Bruce Rock]

I decided to check my blend door actuator. Its not working.

Is it getting the engine vacuum it needs to work?

 

[Bruce Rock]

I decided to check my blend door actuator. Its not working.

Can you move the actuator door by hand? I would want to make sure it's not jammed before giving Ford any more money.

 

[Frankdm83]

You can get a conversion kit from r-12 to r-134A for about $30-$35 at Advance Auto Parts. They come with all the fittings, stickers, and r134a you need. Also, they have a full line of quality A/c parts

 

[Fiberford]

Need some more help, if you guys don't mind. I bought a manifold gauge set from Harbor. With the system off, I'm reading 82 on both sides. With the system running, I reading about 38 on the low and 225 on the high, outside temp is about 90-95. Can't seem to get air colder then 66. Still cutting off on higher RPMs. When I rev the engine to 2500 rmp's the low drops to amost or past 25, at which time it cuts off. If it stays above 25 and doesn't cut off, I'm reading 275 or 285 on the high side. I've replaced both high and low side cutoffs and the WOT relay. Not to mention the return line, condensor, accumulator, and orifice tube. My drive today to Charleston in this heat is going to suck.

One thing I found wierd. The directions say to have both valves open while testing with the system running. Won't this transfer high pressure to low pressure?