FOCUS A/C Grenade!!! Help

[mikedyj]

I had my A/C clutch grenade on me... so i replaced the clutch and hooked everything back up...belt works fine but button on and nothing.. The button light turns on for 20 seconds then blinks and retries to initiate again but noting... the fans turn on for cooling as soon as i turn on button but the clutch doesnt even try to engage or make a noise. Pressure was really high on low side.. i dropped it to 40 psi.. it was in the red.. Not sure if i burnt something electrical when clutch toasted the first time.. Thanks

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[tmittelstaedt]

AC clutches don't wear out, generally, they burn up when the AC compressor seizes. If your pressure on the low side was "really high" then it sounds to me like the compressor blew gravel into the A/C system or somehow foreign debris got introduced into the system.

Reminds me back when I was 16 years old visiting my grandparents, they had an old Oldsmobile 98 (I loved that car) one day we are driving and started smelling something burning - I make them pull off into a parking lot and pop the hood - and there was the telltale smoke rising up from the AC compressor clutch.

They took it to a garage the next day without me then 3 hours later they are back "They fixed it" "How" I ask. "Oh the mechanic said the AC clutch was broken and he replaced it" I'm like "WHAT?"

So I make them drive right back to the garage - sure enough, we pull into the parking lot of the garage and I'm already starting to smell the new clutch go - they made the mechanic come out and stand there watching while the brand new clutch burned up in front of him.

This was in Arizona. Let me tell you, AZ is stuffed full of old people who don't know how mechnicals work, and every corner garage has a big old sign saying "we fix auto A/C" and the state is stuffed with mechanics who think they know how to fix A/C systems - but don't. It is scam city. I saw more half-assed A/C "fixes" being done down there, taking advantage of the old grandmas and grandpas, than you can shake a stick at.

The ONLY time you should ever be buying a brand new AC compressor clutch is when you just took delivery of that new rebuilt compressor and it didn't come with a clutch for some crazy reason.

IMHO your system needs to be completely dissassembled and all freon lines flushed, then new compressor & accumulator, and the orifice must be checked for blockage and the screen cleaned.

A/C systems are simple to work on but they have to be absolutely clean-room clean when you put them back together or you will simply seize the next compressor. And you need at minimum an electronic leak detector, vacuum pump, guage set, and can tap. And I usually run the vaccum pump on them for at least 4 hours to boil out any water if I've cracked the freon lines for any reason.

[amc49]

'AC clutches don't wear out, generally, they burn up when the AC compressor seizes.'

Hmmmm. Not in my experience. I've repaired at least 5 clutches and not a single compressor in the last thirty years and on several personal cars. The bearings shell out since the pulley always runs. Common enough so that I started replacing the bearing alone and filing the clutch flats to let them run in again. That allows back up and running for maybe $40.

Now if in the shop, yeah, one does not sell the parts separated, rather as an assembly. Be a moot point before long as getting harder to find clutch by itself.

X2 on compressor here, probably lunched. The difference there is easy to tell.

I feel most of the 'a/c specialist' work here is pure scam also.....................

[whynotthinkwhynot]

It's probably something in the controls. You have a high and low pressure switch which protect the system. The high pressure switch protects the system from over pressure which could cause a rupture in the lines- most likely the rubber lines under the hood. The low pressure switch prevents the evaporator from collecting ice. Low side (suction) pressure is directly related to the temperature of the evaporator- and what you feel in the cabin. Lots of people call that the cycling switch.

I would expect to see high pressures when the compressor is not turning- static pressure. Typically it will be something like 10-20 psi above ambient temp in F, so if its 80F outside, expect 90-100 psi from either port. When the compressor turns on, you should see low side pressure drop, and high side (head) pressure increase. IIRC, the head pressure should be about 140-160 at 80F, and I'm not sure when the high pressure switch kicks in- likely around 240 psi or so because that's under what the rubber part of the hose can handle. You could be tripping this switch, but there's no way to tell without a set of gauges. If you have a high side gauge, give us an idea of where you think the high pressure switch trips out- if you can.

Finally, it could be something else in the control circuit. The only other things are the fuse, the relay, and the interior switch. You might be dealing with an evil coincidence. I'm totally with AMC49, the clutch and compressor might be together, but one doesn't necessarily KO the other except in the case where the compressor locks up and the clutch tries to stay on- and in that case I think the belt would go before the clutch.

Try swapping relays with the low beam headlight relay. Those should be the same. It does seem like the compressor is doing it's job. You can then test that relay using your headlights. Be careful when removing relays. Resist the temptation to pry with something. Hold down the relay box with one hand, and wiggle and pull the relay with the other hand. Remember, your car is 13 years old!

[tmittelstaedt]

"...I've repaired at least 5 clutches and not a single compressor in the last thirty years and on several personal cars. The bearings shell out since the pulley always runs..."


interesting I wonder if that's the type of compressor - most of the AC work I've done has been on GM vehicles with the Frigidaire compressors - because those are the ones that break. I have owned Ford's and a Datsun with the York compressors and those never died - of course those also were R12 systems.

[amc49]

Never owned a GM to tell but dang sure sold plenty of the compressors though.

I always had York or 10P15 or FS10.

Thinking the high pressure valve blows off at 400+ psi. I've heard elsewhere 450. A standard R134 system can easily touch over 300 psi highside in Texas summer. I usually set mine close to there on a 100+ degree day. I use a cut-off point of at least 275.

The high pressure switch is not made for actual regulation all the time, rather as a last gasp failsafe to prevent hose blowout. They really should never come on in normal use.

If highside switch were the problem, compressor should at least come on for a second or two, run up to the limit and switch then kills it. Of course either switch could be bad.

[whynotthinkwhynot]

Didn't the OP say that it came on, dropped to 40 psi on the suction side, then cut off? He might have a bad switch too, but if the relay doesn't fix it we'll go there. It could always be a bad compressor- just the breaks that both go out at the same time.

[whynotthinkwhynot]

No wait, I re-read that. He couldn't get the AC to turn on, so somehow he dropped the pressure......meaning released refrigerant. So it won't run now if he's only at 40 psi static pressure. I think the OP is about to learn how AC works whether he/she wants to or not. The first step would be stop listening to people before you check. ACs are sort of like electricity, the unknowing end up taking a lot of advice that doesn't fit exactly.

[amc49]

Brother you SO got that one right! Most a/c common knowledge out there is at best worthless and at worst downright dangerous.

The ones I've worked on pretty much start up compressor around 25 psi if things working right.

Sounds like to me someone should crawl his happy butt up under there and verify whether the compressor is locked up or not first. If he read lowside pressure at static then he let refrigerant out for no reason at all just like someone else just did here onsite. A whole lotta unsaids in there and no way to give clear direction. What's this? I seem to be talking to the ether................!

[mikedyj]

Originally Posted by mikedyj

I had my A/C clutch grenade on me... so i replaced the clutch and hooked everything back up...belt works fine but button on and nothing.. The button light turns on for 20 seconds then blinks and retries to initiate again but noting... the fans turn on for cooling as soon as i turn on button but the clutch doesnt even try to engage or make a noise. Pressure was really high on low side.. i dropped it to 40 psi.. it was in the red.. Not sure if i burnt something electrical when clutch toasted the first time.. Thanks

Thanks....im on the up the arse move now..... lol i will check the rotation on the compressor to see if it even moves....