Hot Rods 30 year old brand new Ford AC compressor hard to turn

I found a brand new Ford OEM never used or mounted AC compressor and it was sealed with the caps for 5.0 that I am putting in my 38 Ford Truck. It was full of thick viscous Mineral Oil which I drained. The compressor is little hard to turn which I ***ume due to the viscous oil. I dont want to do anything to ruin it.

Is that normal for Mineral Oil ?

What is the best way to free it up ?

 

Are you trying to turn it with the caps on?

 

No! I removed the cap and drain all of the old oil out.

 

I have installed some reman compressors that turned stiff but worked fine. I think once it runs it will loosen up.

 

New compressors are often shipped with the PAG (PolyAlkaline Glycol) oil that is required to lubricate them already in place.

This is done so that the correct grade and volume of oil is present, and no "installer error" can occur.

You drained it out. You will need to determine the grade and volume, and put it back in, if you intend to use it.

 

I’d think it should spin freely, even with the caps unless the clutch is engaged on it?

 

Good point. Current is required to engage the clutch. The pulley should spin free, or close to it.

 

The pulley spins freely since the cluth is not engaged. I am rotating the clutch. The oil that came out was very viscous. I will be converting it from R12 to R134a which is why I drained the mineral oil.

 

It is the compressor that sets the lubrication requirement, not the refrigerant.

The static parts of the system require no lubrication.

 

Not quite true. When we changed to R-134A at Freightliner, we were using the same compressors but went to PAG oil. If I remember right is was because R-134A wouldn't carry mineral oil through the system the way R-12 had. With that said, different compressor manufacturers specify different oils. Most use a specific grade of PAG oil but some will accept Ester oil. If you go to a parts store they will tell you that Ester oil replaces any other oil.

 

Mineral oil is not compatible with R134a, the refrigerant has to carry the oil around the system in suspension.
Mineral oil in a R134a system will destroy the compressor in short order.
Pag is the best to use but will not mix with mineral oil which is why ester oils are used during conversions.

 

Consider it take a few HP to turn a AC while engaged, do you have another vehicle with AC you could pull the belt and compare?

 

Ok, let me re-phrase:

The compressor still sets the lubrication requirements. It may not set the particular chemical composition, in regards to compatibility with the refrigerant.

If the lubrication that is subs***uted does not meet the lubricity requirements of the pump, it won't matter if it is compatible with the refrigerant. You will be out a compressor.

 

Are you putting in a new evaporator and condenser? Do you know how much oil the system holds (Estimate)?
I would recommend putting ester oil in the system.