A/C problem

[Flycat]

Hello,

 

I had the head gasket in my 98 legacy wagon replaced over the winter and was wondering if that may have anything to do with the AC not working?

 

I was tossing around the idea of trying one of those DIY recharge kits or having the system looked at by a shop.

 

The fuses all look ok and while trying to diagnose it on my own I found that when I put a 12v test light at the base of the relays, the fans would kick on. One fan would kick on when checking one relay, the other would kick on when checking the other relay. I've read that the system has a mechanism that shuts down the compressor when the refrigerant is low?

 

Thanks

Edited July 25, 2010 by Flycat

[Fairtax4me]

Is the compressor clutch plugged in?

Do you have any traces of oil around the compressor? That would indicate a bad O ring causing a leak.

 

You can try a recharge kit. They work fairly well as long as you don't use the gauges that come with them. Get a small can, and if one can makes it start working then a second small can should be enough to top it off. If you want to do it right, buy a manifold gauge set (about $50 for a cheap one) to check the system pressure.

[Flycat]

I put a can of the leak detector r134 and a second small can. Some interesting results.

 

1) I found a small leak where the return hose goes into the compressor. It's funny, because it looks like the clamp holding the hose in belongs there, but thee's an empty threaded hole, as if there should be a different clamp being held by 2 bolts.

 

2) Upon putting r134 into the system the compressor kicked in, abeit off and on. When the compressor ran the system blew cool air.

 

3) The compressor was off more than it was on when I had a less than full can attached to the return so I began to mess with the relays. When one of the relays was barely placed in it's socket the compressor ran and it sucked in the rest of the can of r134, however it wouldn't stay running. For a while I could play with the relay and get the compressor to run, one time as long as 10 minutes, in which time the car was nice and cool. Not cold, but definitely a marked improvement.

 

Could it be the relay? Or could it be the fact that there is barely enough r134 to make the system operate?

 

I've read that you can jump the compressor clutch, forcing it to run so it takes the refrigerant. How do you do this?

[Rooster2]

I put a can of the leak detector r134 and a second small can. Some interesting results.

 

1) I found a small leak where the return hose goes into the compressor. It's funny, because it looks like the clamp holding the hose in belongs there, but thee's an empty threaded hole, as if there should be a different clamp being held by 2 bolts.

 

2) Upon putting r134 into the system the compressor kicked in, abeit off and on. When the compressor ran the system blew cool air.

 

3) The compressor was off more than it was on when I had a less than full can attached to the return so I began to mess with the relays. When one of the relays was barely placed in it's socket the compressor ran and it sucked in the rest of the can of r134, however it wouldn't stay running. For a while I could play with the relay and get the compressor to run, one time as long as 10 minutes, in which time the car was nice and cool. Not cold, but definitely a marked improvement.

 

Could it be the relay? Or could it be the fact that there is barely enough r134 to make the system operate?

 

I've read that you can jump the compressor clutch, forcing it to run so it takes the refrigerant. How do you do this?

 

 

When the system is low on refrigerant, the compressor will cycle on and off in short bursts of about 3-5 seconds. If it were me, I would add another can of 134 refrigerant to see if that lengthens on/off cycle times, before swapping out the relay.

 

You need to see if you can stop the small leak before adding refrigerant, or if it is just a very small leak, then adding the second can of refrigerant just might get you through the heat of summer before running out.

[nipper]

Solve the leak first. I would replace that O ring where the missing bolt is (do not hurt yourself on the refigerant). Then replace the bolt that is missing. Get a gauge set and fill up the system and you should be golden

[Fairtax4me]

Solve the leak first.

 

Agreed. If you don't fix the leak you just lose all of the refrigerant and the money you spent on it.

 

The compressor does not run continuously even under normal operation. It has to turn off periodically for the pressure in the high side of the system to bleed down. Pressure makes heat. And too much heat leads to a vicious snowball effect that ends with the compressor imploding.

This also gives the evaporator core a much needed chance to defrost. If the compressor ran constantly, the evaporator would plug up with ice (condensation from the air moving across it), or the high pressure lines would explode from overheating, or worst case the compressor melts down and seizes.