A/C clutch trouble?

[thekauz]

I have a 91 loyale with an A/C problem. I was charging the A/C system with R12 and when the A/C was turned on it would run for 10 seconds and then the clutch shutoff off. When I would turned the system off and back on it would work for 10 seconds and the clutch would cut out again.

Following an earlier thread I found on this forum I jumpered the belt protection system. The A/C clutch engaged and said engaged. temp out of the A/C was 57 degrees F.

 

My question: Is it OK to leave the system running like this?

 

Also is the pulser bad? Is it turning off the clutch? Is their a test for the pulser?

[djcommie]

What does your gauge manifold say for low and high pressures? Did you fill a system that was vacuumed, purged, and with the receiver replaced?

[thekauz]

Its an all original equipment system and no it was not vacuumed and purged. I hace read on other threads is ok to run the system jumpered to bypass the belt protection system. Car seems to run fine. I guess I need to figure out why the A/C compressed turns off after it run for 10 seconds.

 

is there a test procedure for the pulser that usually causes that problem??

[djcommie]

Without the correct tools, you're going to destroy the system. An empty system absolutely requires a new receiver/dryer. Water combines with R12 oil and creates acid, corroding the lines and eventually destroying the TXV and compressor. I don't know how the pulser system works, but I imagine your compressor stops because the low side pressure drops too low and trips the low-pressure cutoff switch. R12 is expensive, R134 is less efficient and requires every o-ring to be changed to HNBR, and R152 isn't type accepted in automotive applications (is slightly flammable).

 

Without an understanding of how phase change refrigeration works, a mistake can permanently damage the system or you can injure yourself. 

[idosubaru]

I may be charged too low or too high.  What are the pressures?

I would not jumper an A/C system to get it to run.

 

I always replace orings and charge Subaru's without vacuuming or replacing anything. Subaru's routinely go 100,000 miles without issues. Subaru A/C systems are robust and rarely have issues. I never replace receiver/dryers in Subarus, though they're inexpensive so why not on one that's so old? While things can happen, and they may be more common in other manufacturers systems - they very rarely happen in Subaru's.  Here's my write up with 14 pages of other people that have done the same over the years:

 

http://www.subaruoutback.org/forums/99-do-yourself-illustrated-guides/43428-diy-c-air-conditioning-leak-refrigerant-repair-5-less-15-minutes-less.html

 

So far not one person has come back to say they're A/C exhibited issues.  Same here, I've never seen a failure after I've worked on a Subaru a/c system.

 

I ***would not*** apply this approach to other less-robust systems on other manufacturers vehicles.

 

I totally understand people who are scared or uber-technical and that has it's place.  But realistically speaking there are plenty of people that appreciate an approach that's inexpensive and has a high percentage of success.

 

All that being said - it needs properly diagnosed.  what was the original issue?

 

If the pressures end up not being the problem then look into

1.  relays in the system

2.  the a/c compressor clutch

Edited July 23, 2014 by grossgary