AC system issues

[daniel.drives]

Alrighty boys, it's mid june, which means it's time for AC questions.

Two weeks ago, as I was cruising down the highway in phoenix, the AC went from blowing nice and cold to ambient temp for about 20 minutes. I assumed it was an EATC issue, and left it for the time being.

Yesterday, on my way from San Diego to Phoenix, the AC died in Blythe CA. I assumed it was the EATC acting up, so I removed it from its slot, removed the glovebox, and verified that all the vacuum actuators and the blend door actuator works (they do). I also topped up the R-134A, it took about 3 seconds until it was at the correct low side running pressure of 55psi.

Today, the AC didn't pretend to blow cold, and when I got on the freeway there was a buzzing sound and a noticeable lurch each time the compressor engaged. After some more driving, it became apparent that below 1500 rpm, the AC would work normally and it would blow about 60* at the vents, above 1500 rpm it does the buzzing lurching thing and blows at ambient temp.

Am I in for a new compressor/clutch/orifice tube & co., or is there something else I should look at first? Thanks

[03Merc]

I'd say replace the compressor, drier, and orfice tube. It shouldn't just take 3 seconds to charge the system. It has to be done with the machine. To recover it and recharge after vacuum You're looking at 15-20 mins. Have a professional add some dye into it and check with the violet light for leaks.


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[Marauderjack]

The AC's did that in my CV's and the Marauder....watched an AC man remove a shim from the AC clutch in one of my CV's.......FIXED!!:beer:

It seems high mileage cars experience a widened AC clutch gap from wear and the magnetic exciter cannot hold the clutch firmly at higher RPM's......there are normally several shims in the compressor clutch from the factory to get the correct gap!! Removing a shim or two may do the trick.......you'll have to make or rent a tool to hold the clutch while you remove the bolt!!:coolman:

I recall about 0.015" is the max gap allowed........I removed all shims in my Marauder at around 200K miles...worked flawlessly from then on!!:D

[blazen71]

The AC's did that in my CV's and the Marauder....watched an AC man remove a shim from the AC clutch in one of my CV's.......FIXED!!:beer:

It seems high mileage cars experience a widened AC clutch gap from wear and the magnetic exciter cannot hold the clutch firmly at higher RPM's......there are normally several shims in the compressor clutch from the factory to get the correct gap!! Removing a shim or two may do the trick.......you'll have to make or rent a tool to hold the clutch while you remove the bolt!!:coolman:

I recall about 0.015" is the max gap allowed........I removed all shims in my Marauder at around 200K miles...worked flawlessly from then on!!:D

Still works at 275K!

[Marauderjack]

TADA!!:beer::D

It really is amazing that automotive components can live that long Dave!!:eek:

[daniel.drives]

Thanks guys, I'll give that shim trick a shot before dropping $300 and all day on new parts. I'll let you know how it goes!

[justbob]

Check for a vacuum leak. The black box on the drivers fender is a holding tank for vacuum so when you’re accelerating and making little to no vacuum it won’t effect the performance of the A/C.


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[MyBlackBeasts]

My clutch failed where the thin plate part of clutch cracked and would drag when disengaged and not fully engage when magnet activated.

$80 I think from Rock auto and 45 minutes = good as new even 6 or so years later.

[FordNut]

My ac quit, it turned out to be the engine cooling fan. The ring around the outside edge of the blades broke and jammed against the shroud. Made a loud noise and the ac didn't cool so I thought it was the compressor but found out otherwise. I've had two of them do the exact same thing. Left that way long enough, the engine will overheat too.