I’ve recently noticed the A/C performance on my XKR getting progressively worse, but only under certain conditions:

Symptoms:

• On cold morning starts: blows ice cold immediately and stays cold the entire drive.
• If the car sits parked in the sun and the cabin heats up: the A/C barely cools at all.
• Driver side blows slightly cooler than passenger side when this happens.
• After about 5 minutes of continuous driving: air begins getting colder.
• After about 10–20 minutes of nonstop motion: both sides blow evenly cold.
• As soon as I stop at a red light or stop sign: air warms up again.
• Nighttime / rainy days / cool mornings: works perfectly at all times.
• Increasing RPM while stationary only helps minimally.
• No error codes from the climate control system.

What I've checked so far:

• Both radiator/condenser fans run at full speed when A/C is on.
• I suspected low refrigerant, but a gauge on a recharge can reads firmly in the green.

So essentially, the A/C cools only when the car is moving and looses cooling when stationary, especially after heat soak.

Has anyone experienced this on their XK8 or XKR? What components are the usual suspects?

 

I would not trust what a gauge on a can of recharge tells me. I have seen several XKs that do this and it has always been due to being a little low on charge.
If you areny over 30 PSIG on the low side and 2.5 times the ambient temperature in Fahrenheit( 80 degrees=200 PSIG), then you are low.
A weak compressor could also cause this issue.
Hope this helps

 

Ok, so you are saying I should get a proper set of gauges first?

 

Can't hurt - I mean a second opinion to a disposable gauge on a can of refrigerant that has been sitting on a shelf for who knows how long isn't a bad idea.