AC Air Conditioning Cold then NOT!

[GTOSHO]

I'm having trouble with the AC on my '94 MTX. Its ice cold when I first start the car cold in the morning, but after a few minutes of driving it goes warm. While I've done most everything else mechanical on a car, the AC system is one I've never messed with.... I'd like to know the best source to educate myself on the subject. I'm fairly new to this vehicle and don't even know where all the components are located. I'm thinking I need to check the coolant charge level first. Need a pressure gauge of some sort connected to where? Which gauge is preferable? If ok, check compressor clutch and coil? Maybe try to shim air gap? I've gathered just enough info from this site to be dangerous... Thanks for any help. Tim

 

[Dave Kegel]

It's most likely the compressor clutch. They're pretty easy to replace, about $50 or so from Ford. Some have had luck removing the existing clutch, and then removing one of the two shims in order to get the air gap back in spec. I just went ahead and replace mine since you have to remove the old one anyway. It's held on by one nut, then you can pry it off with a couple of small screwdrivers.

Since it starts out blowing cold, your freon level is probably fine..

Dave Kegel

 

[Slo-Sho]

I removed one of my shims and now it works great.

 

[GTOSHO]

Checked things out again today. Started up, cold AC let idle, continued cold AC, after a bit brought the revs up and down a bit, still cold, rev it a little higher and it goes warm. Check the compressor, clutch not turning, while looking at it, it starts up again and we're back to cold AC, car's now been at full operating temp and it 84 degrees outside. Do the same thing with revs and get it to shut down again. Take a piece of PVC pipe and whack at it, nothing happens the first couple times, then it starts back kinda slowly then engages. Once again bring revs up and hold til it quits and now can't get it to come back on.

Is this absolutely a sign of a bad clutch? Could it be another system shutting it down? If I go the replacement route, do I need just the clutch or coil/switch as well? May just try pulling a shim for a cheaper solution? Thoughts????

 

[jthomas68]

How do you hold the clutch from spinning to remove the bolt?I had the exact same issue for 2 days.Now it won`t come on at all,so i figured i`d check the gap.It`s at the extreme high range,or just out of it,but i can`t figure out how to hold the clutch tight to remove the bolt.

 

[drdave]

Go to AutoZone or O'Reilly. They will loan you a tool that's made just for that purpose. And then it will take you about two seconds to get it off.

 

[GTOSHO]

I struggled but finally prevailed and got the clutch off! (I made a makeshift spanner wrench with a couple of metal screws into a plate (to pick up two of the 6 clutch hub holes) tied to a 1 X 1 for some leverage to get the 12mm nut loose). Was hoping to remove one of the two washers (I did find a thin one and thick one, not the half washers I expected, but full ones) but the clutch face looks to be really worn, down to a rivet in one place (warped or misaligned?) and it looks to have been riding the serpentine belt pulley as well! So my question now is what all needs to be replaced? What is the next piece that comes off the compressor that engages this clutch hub? I don't see any friction surface only metal. Is there supposed to be something there?

 

[GTOSHO]

One more thing, assuming a "clutch kit" (hub, pulley and coil) is what I need, is Ford parts the only way to go, got quoted $237 (with tax) from the local dealer. Called a local autoparts store > $129. Quality? What are the cheapest sources for both the Ford and aftermarket lits?

Thanks, Tim thumb

 

[Slo-Sho]

jthomas68:
How do you hold the clutch from spinning to remove the bolt?I had the exact same issue for 2 days.Now it won`t come on at all,so i figured i`d check the gap.It`s at the extreme high range,or just out of it,but i can`t figure out how to hold the clutch tight to remove the bolt.

There should be two shims, you will want to remove the thinner shim first and recheck the gap.

 

[projectSHO89]

AutoZone and Parts America have remanned units starting at around $72.

Personally, I would probably pick up a new aftermarket kit from either store for around $100.

Make certain that you get the one for the Nippondenso 10P15F compressor.

Steve

 

[rangerj]

GTOSHO,

Aftermarket, that is the local parts store, clutch assemblies are fine. Chech your service manual for the recommended gap between the clutch surfaces, but .035 should be fine.

The gap is set by inserting or removeing washers of differing thickness into the clutch face where the compressor shaft goes.

The "metal" surfaces are the clutch surfaces. There is no "friction" material other than the metal you see.

The clutch face can be held with a "Strap wrench" for removing the nut or bolt that holds on the face to the compressor.

If you are going to replace the clutch assenbly then two screwdrivers can be used to pry apart the face from the pulley ( actually you are "pulling" the face fron the compressor crankshaft).

I would use two wood shims to pry the face from the pulley surface if I am going to re-use the clutch face and pulley. (Actually I have a puller for this purpose)

Once the face is off, then the pulley and the coil are held on by snap rings. When removeing the snap rings notice that the snap rings have a "beveled" side facing outward. When you put it back together the beveled side should face outward, i.e. should face you.

You may find it easier to remove the four bolts holding the compressor to its bracket so you can tilt the compressor for easier access to the snap rings. There is not a lot of room to work down there.

Since you have a 94 it should be filled with R-134a. You should have "quick connect" type ports for the high and low side guage connections. If your ports are schrader valve "threaded" ports then your system may be filled with R-12.

It is my understanding that some early production 94s had R-12 in them. The cut off date for R-12 was sometime in 93, and as you know production on a car starts the summer before the model year.

There should be a label on the car telling you what type of refrigerant is in the car.

You can borrow guages from Auto Zone for a deposit. As you get into it and more questions arise shoot them out to the forum. rangerj

 

[GTOSHO]

Thanks all for the responses/help. I'm going to buy an aftermarket clutch kit since I think the wear surface on the clutch hub, since down to rivets is pretty much toast and the pulley must be about the same. Probably don't need a new coil but I guess its good insurance and since its nearly all apart wink

Took the alternator out and found the top two bolts (actually one long bolt and one nut on a stud) on the compressor. There's four total, huh. Two more tucked underneath and need to be accessed from under the vehicle?? Is there any danger of breaking lines while trying to get this thing tipped up to get at the snap rings?

Thanks again thumb

 

[rangerj]

GTO (Grande Tourisimo Omligato)SHO,

There are a few places that sell the clutch face and pulley as seperate pieces. By the time you buy the pieces you can have the whole clutch assembly for a couple bucks more. IMHO get the assembly.

Next, you will not break a hose by tilting the compressor to get at the snap-rings, but you could pop a connection. So, support the compressor so you do not over stress the lines.

Lastly, you are right about the clutch surface. If it is down to the rivits it is shot, and the bearing cannot be far behind. When you turn in your old clutch assembly, keep the old "shim" washers. They could come in handy. rangerj thumb