[FWGTO]

I have a 1970 convertible GTO, with factory a/c. I recently purchased the car and the seller had advised me that the a/c did not work. Seller claims that it just needed to be charged. The seller had installed a belt on the compressor. I did not run any checks when I got the car last month. Last weekend we were driving the car (had maybe driven the car 30 miles since I got the car) and all of a sudden smoke poured out from under the hood. The a/c compressor belt was so hot it was boiling. Not a good sign! It appears the bearings in the a/c compressor seized and since the engine was running, it heated the belt up to the point that it melted. Very smelly situation. I cut the belt off and drove home.
My question concernes the compressor. Should I have it rebuilt or replaced? I am not an expert on GTO's and do not know if they were VIN number specific or if they are generic to the model year.
Any thoughts would be appreciated.
Best Regards,
FWGTO.

[wheelspin]

to the Forums.

Autozone sells re-manned A-6 compressors for about $100, including a one year warranty. Our host Performance Years sells reproduction compressor stickers to complete the change over. If you pay the $10 core charge you can keep the original compressor (if it is original) for future rebuilding.

Les

[RAIV55]

If you can turn the front portion of the clutch which has the rubber cushion that would tell you the compressor isn't locked up. Normally the compressor clutch bearing locks up. It's an easy fix for anyone that has the right tools and not beyond the scope of a do-it-yourselfer with a service manual.

[FWGTO]

Thanks so much for the reply. I can turn (with some resistance) the front portion of the clutch with my hand, clockwise for multiple rotations. If I turn counter clockwise, after a rotation, it will not move any further. Looks like I need to purchase service manuals!

[FWGTO]

Les,
Thanks so much for the information regarding Autozone and Performance Years. Also, I appreciate the welcome to the forums. I am a newbie, but I sure love Pontiacs, going back to my first car- a 1967 Firebird.

[engineer]

if the bearing seized on the clutch enough to melt the belt, that front compressor seal on the shaft would be no good, so either that compressor needs to be rebuilt if the case is original to the car or just get another compressor, either rebuilt or new. Freon is too expensive to mess around and the clutch kit is as much money as what I pay for a rebuilt compressor.

[RAIV55]

Originally Posted by engineer

if the bearing seized on the clutch enough to melt the belt, that front compressor seal on the shaft would be no good, so either that compressor needs to be rebuilt if the case is original to the car or just get another compressor, either rebuilt or new. Freon is too expensive to mess around and the clutch kit is as much money as what I pay for a rebuilt compressor.

Just because the bearing locked up doesn't necessarily mean the seal is bad. The seal is a ceramic unit and it's tucked quite a ways back of the hub the dual row ball bearing runs on. Not to say that it can't happen but very seldom seen the seal go bad as a result of the clutch bearing failure. I'm talking a bearing replacement instead of the whole clutch assembly by the way, should be less than $30.

If there is still refrigerant in the system the seal is holding, if not look for the oil stains that would indicate a leak. At any rate it don't hurt to take a look before whipping out your check book.

[FWGTO]

Is there a way to tell if the case is original?

[FWGTO]

I have not seen any oil stains on the inside of the hood. would that be the logical place to find them?

[RAIV55]

Originally Posted by FWGTO

I have not seen any oil stains on the inside of the hood. would that be the logical place to find them?

If an AC system has much of a leak you will find refridgerant oil stains. Yes it can be under the hood. Also visually check hoses, their connections, fittings and all components of the system.

[engineer]

if you can get by with just the bearing okay, but if the belt melted, that means the heat was into the clutch discs and the pulley etc. I would replace the clutch, so you might as well do the compressor.

[FWGTO]

I rechecked the underside of the hood tonight. Yep, oil stains and residual from the fan belt.

[FWGTO]

I figured I might have to do the compressor. Not real excited about that, but I do think I am going to end up with a bigger project than I first expected, because one of the hoses appears to be secured with (not sure for the proper term) contraction clamps, that you screw tighter with a screw driver. I did not know that freon could be kept under pressure with that type of clamp. The hose in question comes from the condenser to the back side of the compressor.

[wheelspin]

As mentioned previously, the cost of freon makes it important that you do the job correctly the first time, avoiding losing the gas to bad connections or crummy hoses.

I would replace the compressor which INCLUDES the clutch and new bearings, "O" rings in the connections, and all hoses. After cutting the new hoses to length and "clocking" their positions on the fittings, take them to a a/c shop and have the crimp style collars installed as in my pic of my 2 gen Bird system. This clamping method is vastly superior to the factory screw clamps. I also recommend using the higher cost R12 for it's colder discharge temps instead of the lower cost 134 conversions, which work well in some, but not all, systems.

Les

[pont3]

Based on my personal AC experiences I'm gonna have to agree with Wheelspin and suggest replacing the compressor and condenser and even the receiver/dryer or at least a thorough flush of the condenser. Usually when the compressor locks up it is internally destroyed and bits of metal and debris ends up in the condenser. Replacing only the compressor will lead to short life. Therefore, most remanufacturers won't warranty the compressor unless these are replaced as well. Just my experience.

[mikeb]

The compressor clutch freewheels unless the A/C is turned on, which locks the clutch and turns the compressor.

If you were driving along without the A/C on and it locked up then both the compressor and the clutch are toast. Junk and replace both.

[FWGTO]

That is exactly what happened. I was driving along with the a/c off and it locked up. I will look into replacing both clutch and compressor. Just out of curiosity, wheelspin mentioned replacing the factory screw clamps with crimp style collars. Sounds like a good idea to me, since my GTO is not 100% original (has a handful of non-build sheet changes-about 4, as best as I can determine). Are there other upgrades that make our cars more reliable, without materially affecting value, or is the question too broad for an answer?
Thanks

[LASJayhawk]

I was driving my 65 Bonneville with the a/c off when the smoke came out, when I pulled over the belt was boiling rubber. I cut the belt off, and replaced the clutch bearing about 2 weeks later. That was 4 years ago, and the A/C still works fine, and I still have a full charge of R-12.

Just replace the bearing. If the compressor goes out later your out $23 for a bearing, and you'll have spent about $30 on the tooling to change the bearing.

The P/N for the bearing is 5908-VAW.

If you choose to replace the compressor you will need the equipment to recover the freon so you can open up the system, and the equipment to evacuate the air that gets in once you have resealed the system. Or farm the job out. But most A/C shops will expect you to buy the compressor from them, and will want to replace the receiver dryer and the condenser, with some R-12 expect to pay around $1,200.

[LASJayhawk]

A-6 compressors are tough puppies. With a modified case and a 24 Volt clutch they use them on turboprop aircraft like King-airs. Older King-airs even used the same 12 volt clutch as your Pontiac, with a dropping resistor to adapt them to the airplanes 24 volt electrical system.