2000 4.0 XLS Explorer - AC blows cold, then hot

[lciaccia]

I'm having a strange (to me) problem with the air conditioning on my explorer.

It always blows cold when I start it, but sometime later, begins to blow warm. I believe the compresser is stopping. Sometimes the air conditioner will run cold for 30-90 minutes with no problem, other times it stops cooling after 10-15 minutes. The fan always blows as it should, it's just the air stops cooling.

If I shut off the AC for five minutes, and then turn it back on, it will usually cool again for a while, but not usually for very long once I start the process of having to turn it on and off on a trip.

I don't have a good sense about whether driving conditions affect it, but my sense is that it seems to go out more quickly and frequently the hotter it is and the more I'm in stop and go traffic.

My shop just said the compresser needed to be replaced, but that's $500 I'm probably not willing to spend on the vehicle at this point. But the mechanic did say that he'd not seen a compressor going that did that stop and start type thing. Because of that I was just hoping that maybe it was something else (cheaper) that might be causing it but he was unaware of.

Have you guys ever heard of this? Thanks!

 

[my98nnj]

Did you or anybody else put refrigerant in it recently? What you describe is an indication of an over charge. R134 depends on correct system pressures which are also temperature dependent. The only way to really get an accurate charge, especially if the charge is done on cool or very hot days is to charge from a vacuum state by weight, not pressure.

If the system was charged on a 60 degree day with an auto parts store recharge kit (can and idiot gauge) then it's very possible that on 90 degree days the pressures are to high causing the loss in cooling ability.

Did your mechanic put a set of gauges on it and actually look at both the high and low pressures? Does the shop actually have an A/C machine and if so have they ever done an evacuate and recharge correctly (by weight)??

If you can answer no to any of the above questions, you need to find a shop that has the proper equipment before you start throwing unnecessary and expensive parts at it.

 

[lciaccia]

Interesting possibility.

The thing is I've never put refrigerant in it, and I don't think any has been added in the ten years I've owned the vehicle. So to my knowldege, nothing has changed in that regard from when it was working. It does sound like what I'm experiencing though, so is there anything else that could cause that situation?

I talked to someone in another shop yesterday, and he said it honestly didn't sound like the compressor was going bad...just wasn't the behavior he would expect to see.

I'll probably have them take a look at it, but it's complicated. They are going to have to drive it around until it shuts off, and in the morning, that could take a long time...hours maybe. Probably will shut off quicker in the afternoon, but they are a busy shop that doesn't take appointments, so the chances of them being able to get right on it some afternoon are not good. Such a stupid situation...

 

[my98nnj]

They are going to have to drive it around until it shuts off, and in the morning, .

That's false, and being now you've said nothing has been done on 10 years then it's probably just the opposite, lack of R134 charge.

All that's needed is a set of gauges, somebody who knows refrigerant, a pressure -vs- temperature table and the ability to read. The diagnosis should take no more then 15 minutes, engine running a/c on. There's no need to drive the vehicle. The setup will take more time then to actually read the information presented on the gauges which will clearly tell you what's actually going on.

It sounds more like you need to find a mechanic who knows automotive a/c or is equipped with an a/c machine.

 

[ErnieX]

Had a similar problem - turned out the A/C clutch gap had gotten too wide due to age and wear. Gap should be no more than about a business card. Next time it quits, tap the face of the clutch face with a hammer handle and see if it reengages.

 

[allxlts]

same problem. the pump never turns off. it still runs, just no coldness.

something else i noticed was the duration of the pump running was normally longer then ive ever seen...

 

[lciaccia]

Ok, those are some good leads. Looks like I need to find a mechanic who really knows there way around the AC and are willing to chase it down.

 

[terrinmwc]

I have a 2000 Mercury Mountaineer and just had to put in a new thermastat and a new a/c compressor that went out. It's blowing hot air except when it's first charged. It's very cold then you drive it and it blows hot air. It was charged by an a/c guy with all the gauges but we think it's a vacuum leak..we hear the leak we just can't find it. Any ideas?

 

[lciaccia]

Ok, no dice. I took it in to a place who hooked it up. They said the pressure was all off and then did an evac and refill.

No change, 10 minutes after starting driving, no cold air. $160 down the drain.

Brought it back today, they said it must be the clutch, and the whole compressor needs to be replaced. Not going to do that.

Thanks for your suggestions everyone.

 

[jeepgirl]

A/C cold then hot

I am having the exact same problem in my 96. My mechanic said to try replacing a cycling switch near the low side port. I can't recall what its called, but it was around 15 bucks and took about 2 minutes to change. Unfortunately, it didn't solve my problem. I am going to investigate some of the things others have posted about the pressures being wrong, new compressor, or the clutch issue. I know it wasn't my questiong, but I sure am grateful for all of the responses given.

 

[lciaccia]

Update. Somehow I missed it when it was suggested earlier in this thread, but the problem was indeed having too wide a clutch gap. I was able to fix it myself, as per this link.

http://springerpop.net/F350/air_gap.html