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2003 Legacy H6 intermittent AC issue


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Well folks, I need to tap the knowlege base out here because my dealership service department has me $1100 deep into an intermittent AC issue they can't seem to figure out. Here's the details:

 

Vehicle - 2003 Legacy wagon w/H6 engine

 

Issue - AC will quit at idle and will not return to operation until vehicle is turned off and re-started.

 

What the dealer has done so far - First, they replaced the speed sensor in the compressor (still had the issue) then they said it was the PCM that was causing the issue so they replaced that (still had the issue) then they replaced one of the pressure switches and I think maybe even the condenser temp switch? (still had the issue). They just tried swapping out a known good ATC head unit and that didn't work either. Service rep just called to say that during thier hunting they found a bad serpentine idler pully. They weren't directly suggesting that it might be the problem but they did float the idea that it might be causing a problem with the speed sensor in the compressor. I'm really hoping someone out there has run into a similar issue and might be able to give some guidance. Thanks!

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Welcome to the board.

 

Do your Legacy have the automatic climate control?

 

Sounds like they haven't really diagnosed the problem, they're just throwing parts at it.

 

If it were mine, I'd go through and test/check all the sensors/switches and verify they are reading correctly while running, and when it shuts off to see if that leads me to the problem.

 

If it's the automatic climate control system, they should be able to plug it into their computer and monitor what the control system is seeing from the various sensors/switches, etc.

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Thanks Legacy777. It does have the automatic climate control and they claim that they have monitored the data stream but it dosen't really give them a lot of info. Just that the system has shut down. It's hard for me because this vehicle is being driven by one of my employees that is in another state, and my only interaction with the dealer is over the telephone. This has been an ordeal from the very beginning. After they whacked me $700 to diagnose and replace the speed sensor, they wanted to charge me another $800 to replace the PCM. Thier argument was that the speed sensor shorted out and damaged the PCM. I told them that I didn't buy that theory and refused to pay an additional $800 on top of what I have already laid out. The service manager eventually offered a total cost of $1100 with what was already done and the new PCM. I agreed as long as that was going to resolve the issue. Well, the issue is ongoing and they have tried a few other things without success. They claim that they have contacted Subaru and requested that a field rep or engineer help them with the issue but their requests have been ignored. I'm starting to think that I'm going to end up standing in front of a judge explaining this whole mess and asking for the return of my money.

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Funny you should menion the relay. I asked the service writer today if there were any relays in the circuit that they thought to check. I would be furious to learn that that was the problem. Something like that should have been one of the first things that was looked at.:confused:

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Sounds like they don't have any qualified tech's at that dealer to work on that system. Testing parts prior to replacement is the key - obviously none of them know how to run a DMM or an O-scope. Much of the system could be monitored through back-probing of various connection points using an O-Scope to check the signals to the climate control system, etc.

 

GD

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I have come across this recently on 2000 and up Subaru's.

 

First check/replace the A/C relay. In Legacy/Outback/Impreza/Forester it's in the underhood power/fuse box by the battery. You can usually swap it with one of the radiator fans relays just to test it. The A/C relay, if you open it up, usually had burnt contacts.

 

Now to the other I have seen. A/C seems to work, but on VERY HOT days, or after using it for a while, it just stops. What's happening here is the CLUTCH is no longer engaging. ( usually the ZEXEL Compressors ). The clutch IS getting the 12v to engage, but with the heat, AND PREVIOUS WEAR, the clutch gap had increased and will no longer engage. Let it cool off and like magic, it works again.

When failing and at an idle, you may try to 'carefully' pushing the front plate with a piece of wood ( my choice ) and CLANK, the compressor engages.

 

2 options here, Replace the compressor. I suggest NEW, I would not use a Used one because the clutch on these DOES wear and like buying a used tire, a used compressor already has wear on it. This option also requires vacuum/charge of the system.

 

Please Note, Zexel supplies to its vendors ( Subaru included ) the compressor/clutch as an assembly. They do not supply clutch replacement parts.

 

The other, is buying/borrowing a clutch removal kit ( usually $50 and up ). Remove the clutch. Clean both sides of the clutch surface. DON'T SAND OR ROUGHEN them. Remove a shim or 2 from under the center bolt mount to get the .0011 to .0015 clearance between the clutch face and pulley. I really suggest getting the tool for this. By just removing the 10mm center bolt, the clutch is pressed on and does not easily come off. Prying on the edges of the clutch will bend and destroy it resulting in replacing the entire compressor.

Edited by ferret
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  • 1 year later...

Thank you for this info, This is what is happening on my car. The clutch is worn and the gap is way too large Off to pull the clutch apart and remove some shims!! Yahoo!!!

 

 

Matt

 

 

I have come across this recently on 2000 and up Subaru's.

 

First check/replace the A/C relay. In Legacy/Outback/Impreza/Forester it's in the underhood power/fuse box by the battery. You can usually swap it with one of the radiator fans relays just to test it. The A/C relay, if you open it up, usually had burnt contacts.

 

Now to the other I have seen. A/C seems to work, but on VERY HOT days, or after using it for a while, it just stops. What's happening here is the CLUTCH is no longer engaging. ( usually the ZEXEL Compressors ). The clutch IS getting the 12v to engage, but with the heat, AND PREVIOUS WEAR, the clutch gap had increased and will no longer engage. Let it cool off and like magic, it works again.

When failing and at an idle, you may try to 'carefully' pushing the front plate with a piece of wood ( my choice ) and CLANK, the compressor engages.

 

2 options here, Replace the compressor. I suggest NEW, I would not use a Used one because the clutch on these DOES wear and like buying a used tire, a used compressor already has wear on it. This option also requires vacuum/charge of the system.

 

Please Note, Zexel supplies to its vendors ( Subaru included ) the compressor/clutch as an assembly. They do not supply clutch replacement parts.

 

The other, is buying/borrowing a clutch removal kit ( usually $50 and up ). Remove the clutch. Clean both sides of the clutch surface. DON'T SAND OR ROUGHEN them. Remove a shim or 2 from under the center bolt mount to get the .0011 to .0015 clearance between the clutch face and pulley. I really suggest getting the tool for this. By just removing the 10mm center bolt, the clutch is pressed on and does not easily come off. Prying on the edges of the clutch will bend and destroy it resulting in replacing the entire compressor.

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