Just had the compressor replaced and leaks fixed but the ac blows cold then after 10 minutes or so blows warm and then goes back to cold after 5 minutes. Fully charged. Mechanic wants to take the dash off to look for leaks on the coils? nut if leak air wouldnt get cold again? any ideas? Thanks!

2010 Jaguar XK convertible

 

There are sniffers that would indicate any leak behind the dash, no need to remove anything.

 

New compressor or an used one? Does it blow warm with low idle or at a traffic light etc.? There is a TSB for this problem, often discussed here.

 

I had similiar symptoms years back, came up to be a faulty radiator fan. Inner circuitry had bad connections due to constant vibration in the module, thus intermittent operability, lack of air flow through the radiators. I also had engine overheating problem when vehicle was stationary/slow traffic and engine running for prolonged periods of time

 

great to know - Thanks!

 

New. but did not have this issue when I replaced it. When the cold air is coming back on after a few minutes or more it does seem revving the engine helps. But once it is back it will stay cold for a while until it doesnt.

I don't really think there is a leak, I suspect a sensor or clog or something.

 

Good to know - fortunately no over heating issues that I have experienced.

 

common sign of a failing expansion valve.

 

Thanks - testing it this morning while driving daughter to school ac went out twice and came back each time. When it goes out and I put it on auto the air seems to slow down - is that a thermostat issue?

 

You need your mechanic to hook up a set of A/C gauges and monitor the hi/lo pressures in order to isolate where the issue is coming from.

If it still blows hot while the pressures are where they need to be for your ambent temperature and humidity, you can starting to look at cabine fan blowers etc.

 

I second the Expansion Valve.

 

Could be moisture in the refrigerant which ices and blocks the line at the evaporator, system shuts off, ice melts and you start over again.