Compressor oil etc...

[Ross Wooldridge]

Hey All,

I have to re and re the compressor on the T&C since the clutch assembly decided to retire from active service and in the process, score the snout of the compressor crankshaft and wreck the keyway and the fan.

I have a rebuilt compressor and clutch in the box and I want to know how much oil to add, and what kind... I will be running Duracool in it (yeah, I know, but it works GREAT and is cheap to buy and top up once every 2 years).

Do I use PAG oil? Roughly how much, and do I add it to the little plug hole in the compressor's sump?

Thanks in advance.

Here are some pics of the carnage as I saw when I first opened the hood - it took out all the belts, knicked every blade on the fan (but thankfully managed to keep itself out of the radiator)... thankfully I was only 20 miles from home, and I have everything I need to fix.

 

[Ross Wooldridge]

Yes, I'll be installing a new cooling fan & fan clutch, AC dryer, compressor and clutch, and I have new belts on the wall - even a matched pair of compressor/alternator belts!

 

[furious70]

I don't know on the oil but you're lucky the hood wasn't damaged!
She didn't give you any warning signs it wanted to exit so bad?

 

[CBODY67]

As I recall, the FSM's compressor section details the amount of oil that should be in the sump, how to measure it, and where to add it.

Glad the carnage was not worse than it was!

Just some thoughts,
CBODY67

 

[volksworld]

ouch...I have no idea what is compatible with Duracool but if irc the system usually winds up with 6 or 7 ounces of oil in the compressor itself with the rest distributed into the other components...be careful with dipstick measurements as they vary with whether the compressor is installed laid over on a big block ,level on a small block or sitting on a bench ,and if you have the V shaped pan or one of the flat ones...if you have no clue what kind of oil is in it now rather than mixing 2 incompatible oils you may be better off flushing the entire system, buying a new receiver drier and adding 11-12 ounces...if the system is still original and was never converted to 134 it probably still has mineral oil in it...evidently the bolt in the nose of the crank backed out while the clutch was engaged...torque it to 20 ft lbs and it uses a special thicker than normal washer...you may run into the same issue as I did where the pullys on the new clutch are smaller in diameter than the originals and require shorter belts

 

[413]

It's all in the FSM. You make a dipstick tool, they have specs.

On your own with what type oil though.

 

[Davea Lux]

www.duracool.com/frequently-asked-questions/

 

[Trace 300 Hurst]

Dipstick, as per the FSM dimensions. The portion on the right goes down into the sump. Black paint allowed me to see fresh, clean oil. And yes, it needs that little bend so it can go where it needs to go to the bottom of the sump.

 

[Trace 300 Hurst]

As for what oil to use, you should use whatever is in your system now, since Dura is fine with either mineral or ester/synths. But what's in there now? I see that you have 134 conversion Schraders, but did whoever did the convert actually purge the system of R12 mineral and go to 134 oil? Probably not....hardly anybody does. So, do you fully flush the system with the compressor out of the issue, which allows for a good flush? Wouldn't hurt, and then you know what oil is in the system once you do the oil fill and all that tedious work.

 

[Ross Wooldridge]

Thanks everyone for your guidance here.

The conversion to R134 A was done around 1996, and I know it was done properly (it was expensive at the time to do it), which was likely why the system has lived and performed so well since, and not become sludged up over the years (even though I switched to DuraCool type refrigerants about 10 years ago or so). When the conversion was done they gave me a can of the oil they used, and I'm pretty sure it's the PAG Ester Oil, but I can't remember. I still have the can on my shelf, so I just need to look at it.

Regardless, my inclination is to do as complete a flush as I can, and start fresh, if I can't, I'll make a dipstick as per the instructions above, and measure the old compressor with it inclined the way it is in the car and add the same amount to the new compressor.

I'll be installing a new dryer for sure, new oil if possible, and of course, new refrigerant. Along with new (good used) cooling fan, new fan clutch and belts.

This will give me a chance to clean up the front of the engine too - something that is such a total pain in the butt when all the components are installed.

 

[Ross Wooldridge]

I don't know on the oil but you're lucky the hood wasn't damaged!
She didn't give you any warning signs it wanted to exit so bad?

There were warning signs - I had just taken the car in to have an expert go over the charging system, and it had thrown the belts just as I came into the parking lot. They were not broken, but the compressor clutch was loose (which we thought was the reason for it tossing the belts), so we flipped them back on and checked the charging system, and then I was going to limp it home to change the clutch along with the alternator and regulator (again... another story... sigh).

We thought the bearing was toast, but what had actually likely happened was the snout bolt was backing out and the clutch and pulley had come loose from the snout.

Didn't make it home. No snout bolt, boogered keyway in the snout, and wrecked belts. Probably would have been just fine if I'd checked the snout bolt and tightened it back up.

Such is life...

 

[Ross Wooldridge]

ouch...I have no idea what is compatible with Duracool but if irc the system usually winds up with 6 or 7 ounces of oil in the compressor itself with the rest distributed into the other components...be careful with dipstick measurements as they vary with whether the compressor is installed laid over on a big block ,level on a small block or sitting on a bench ,and if you have the V shaped pan or one of the flat ones...if you have no clue what kind of oil is in it now rather than mixing 2 incompatible oils you may be better off flushing the entire system, buying a new receiver drier and adding 11-12 ounces...if the system is still original and was never converted to 134 it probably still has mineral oil in it...evidently the bolt in the nose of the crank backed out while the clutch was engaged...torque it to 20 ft lbs and it uses a special thicker than normal washer...you may run into the same issue as I did where the pullys on the new clutch are smaller in diameter than the originals and require shorter belts

You are correct regarding the snout bolt...

System was properly converted back in the day and I'm almost 100% positive it's PAG Ester, so things will likely be OK that way, but I'm hopefully able to flush and put all new oil in. What I don't know is how much total new oil for a Dual AC system. Hopefully that info is in my manual.

New clutch has the correct bolt and thick washer, but if you were in my place, would you put Loctite on the threads just to help avoid a repeat? I'll have to measure the pulley to see if it's a different size - haven't considered that yet! Thanks for the tip!

 

[CBODY67]

Loctite Blue?

 

[Rainy Day]

That bolt would get RED Loctite. It is a semi-permanent part.. and once is 1 too many times.

 

[volksworld]

I put blue loctite on mine...figured it couldn't hurt...but I really don't recall clutches falling off as something that happened on a regular basis back in the day... didn't realize yours was a wagon...no idea how much extra oil the dual a/c might use

 

[Trace 300 Hurst]

I really don't recall clutches falling off as something that happened on a regular basis back in the day...

Exactly. I think something else led to this failure, and it wasn't a lack of Loctite. Frankly, that little bolt--torqued to a mere 20 ft-lbs per the FSM--doesn't really do much other than push the assembly onto the "interference fit" taper on the shaft. That "fit" does the work, not the bolt.

 

[volksworld]

Dipstick, as per the FSM dimensions. The portion on the right goes down into the sump. Black paint allowed me to see fresh, clean oil. And yes, it needs that little bend so it can go where it needs to go to the bottom of the sump.

View attachment 669278

View attachment 669279

ok this is the pic from the '75 a/c manual on MyMopar...so these dimensions would only be valid on a compressor that's mounted level and has the flat/stepped oil pan, not the earlier setup

 

[Trace 300 Hurst]

ok this is the pic from the '75 a/c manual on MyMopar...so these dimensions would only be valid on a compressor that's mounted level and has the flat/stepped oil pan, not the earlier setup

It's also from my 70 Chrysler FSM, so whatever pan would have been on those cars. And it sits dead level on the 440.

 

[volksworld]

the FSM's procedure of running the car at high idle with the air on to evenly distribute the oil, then discharging the system to check the oil level isn't exactly practical at the moment...but they said if you couldn't do that just put in 8oz...yes like 69 and up the compressor is level...mine has the later brackets and sits level so I didn't have to deal with it but when I read the procedures in the 68 FSM they weren't easy to understand....about to leave so cant go down to the shop to try to make sense of it right now

 

[Ross Wooldridge]

Thanks.

My 66 compressor is tilted a tad to the passenger side. I'll let you know what my research reveals regarding the oil amount for DUAL AC systems.