My 08 XL V6 has a weird a/c issue that I've noticed for as long as I've had it -- since August of last year (10 months). The a/c works great when I start the truck cold. It works great when the truck is moving. It works great when I have to stop in traffic. But it doesn't work at all if I've shut the engine down for 15-30 minutes then restart. It will eventually work (cool down) if I drive away.

 

When you say it isn't working, can you be more specific? Is the compressor cycling and it's not cooling, or is it failing to cycle?

 

Sorry, but I'm not sure about the "cycling" part. There is absolutely no cooling -- there is only hot air coming thru the vents into the truck. It's not "slow" to cool -- there is no cooling at all and then it magically starts up

 

The compressor uses an electromagnetic clutch to engage. So when the AC is off, the center of the compressor pulley does not spin. With the AC on, the center should be spinning.

When the truck is at idle with the AC on and the blower set to the lowest setting, you can see and hear the compressor engaging and disengaging repeatedly (referred to as "cycling"). With the AC on and the blower set to high, the center of the pulley should be spinning continuously.

Here's a video that shows a compressor cycling.


So back to the original question. When the AC is blowing warm, is the compressor cycling/engaging?

 

Thank you very much for that info -- especially the video. I'll watch the compressor and get back with you . . . .

 

Sorry it took so long to get back to your question but the truck has been behaving itself, for the most part.

But today it was blowing hot air so I popped the hood and the center pulley was NOT spinning. It would start spinning (engage?) for a second or two and then "disengage" and stop spinning and stay stopped for quite a while. It was doing this over and over and the air stayed hot. This time my truck hadn't been started in over a day so the engine was cold.

 

Could be something simple like a low-charge condition. Would need to hook it up to a set of gauges to verify.

But since you describe the problem as intermittent, it may be something else. Either way, a manifold gauge set is where to start.

Sorry I don't have time to go into much more detail. But searching the forum may yield more useful information. If nothing else, here are the pressure specs from the service manual. If you connect a gauge set and find that either side goes out of spec while the compressor is engaged, this will cause the compressor to stop cycling.

A common issue on some older Fords is the compressor relay. I can give you more specific information soon, but not tonight. But search the forum and the internet and you may find some useful information along the way.

 

Hey man, thanks for the time and info. I appreciate it.

I'm not a mechanic so I don't have a gauge set but I will take the truck to the garage and tell the mechanic there what you've told me. I may not take it in right away because the a/c always kicks in within a minute or two when I drive away.

I promise to update this thread with the resolution -- it just may be a while . . . .