Sandin compressor locking up?

-
jaws

jaws

I put the fun in dysfunctional
FABO Gold Member
Joined
Sep 11, 2006
Messages
6,126
Reaction score
6,831
Location
Strasburg Colorado
new radiator, new belts, now when I was checking the A/C, was running good. Compressor was running, then the clutch disengaged, when it engaged again, compressor was not turning, belts smoking. Shut motor down to check everything, looked good. Started it up, compressor turning just fine, kicked off, then back on and compressor not turning. Shut it down took the belt off, put a wrench on the compressor, and was hard to turn. Is this locking up or something else. This is on a Classic auto air system, been on the car for 10 years.
 
The car is cool, just started it. Compressor runs for about 20 seconds, cycles off then locks up.
 
jaws said:
new radiator, new belts, now when I was checking the A/C, was running good. Compressor was running, then the clutch disengaged, when it engaged again, compressor was not turning, belts smoking. Shut motor down to check everything, looked good. Started it up, compressor turning just fine, kicked off, then back on and compressor not turning. Shut it down took the belt off, put a wrench on the compressor, and was hard to turn. Is this locking up or something else. This is on a Classic auto air system, been on the car for 10 years.
Click to expand...
You need to see high side pressure with a set of ac gauges with ac running. Does comp. turn hard with a wrench the next morning?
 
mechanicmark said:
You need to see high side pressure with a set of ac gauges with ac running. Does comp. turn hard with a wrench the next morning?
Click to expand...

Right. You have a gauge I assume. If not, better get one.

The high side is plugged, the fan is not going on when the pressure goes up or the compressor is mechanically locked up.
 
Yep, compressor turns better this morning, Lent my gauges out but never got them back. Guess I will start with tearing out the condenser and go from there to find the blockage.
 
Some Sandens have a small pressure-relief valve on the rear head. I put a PRV on one I installed on my 1964 Valiant. I recall ~220 psig (~$8 ebay). If the belt is tight enough, the clutch will usually slip first. When that happens, it quickly gets really hot and slings molten plastic out. That happened in our 2002 T&C on an afternoon when it was 108 F. I didn't help it by adding a can of refrigerant after it wasn't cooling well enough that morning and measured the low-side slightly low.

But, the pistons can also seize in the bores. That happened in our 1996 Voyager w/ Denso compressor (similar to Sanden). I tore it apart and found the black anodizing had worn off one piston, causing it to jam in the aluminum bore. I had to really beat it out. That was at ~200k miles, so might be about their life in challenging GA and CA where it lived. My guess is that is a sudden event since bare Al likes to stick to bare Al.
 
Most A/C problems show up after a recharge as ppl/techs reclaim the Freon and remove the oil from the system , then never add any oil. Each time there is a leak u loose oil which is needed to help the Freon circulate through out the system. Even though the system is fully charged it more than likely won’t work as good as it could with out the oil which also lubricates the compressor, which in turn wears out the compressor prematurely. Kim
 
There was a lot of oil in the system. I blu some air through the dash radiator and that was the blockage. Ran some solvent through it, now seems to flow well. Got a boat load of oil out of it. We will see, I'm putting everything back together today.
 
That was it, must have been full of oil, solvent cleaned it out. Back together, charged, working like it should. Will have to see how it performs in the long run.
 
You must log in or register to reply here.
-

Back
Top