Hello,

I have a 2006 F150 4.6 175,000 miles in pretty good shape and well maintained.
Lately, the A/C has acted weird. When I first turn it on, it blows air, but the air does not chill until I have a pretty good RPM going. Then it's fine. Once it starts chilling, it's good to go even when RPM is low (like at a red light). It's just the initial acceleration.

Can anyone advise?

Thank you

 

It blows air because the fan is blowing - you need to see if the compressor is engaged.

Have the pressures checked - you might just be a little low on fluid.

 

Thank you very much.

 

This is the correct observation to make.

This is HIGHLY unlikely. If the system were low on refrigerant, it would NOT suddenly start working correctly and continue doing so.

Check the clutch gap.

 

Thank you very much. Will do.

 

How does acceleration effect clutch gap???????????

When diagnosing a problem, it is always best to start with the basics and then add complexity as needed. Otherwise you may be chasing werewolfs because the moon was full when the "problem" started.

 

Hello guys, I'm all fixed up, thank goodness, as we head into hot Texas summer.

Here is what my mechanic emailed me:

The truck was slightly low on refrigerant. The spec. is 2.25lb, and it had 1.60lb. at this level you would not notice a problem until the outside air is over 85 degrees with high humidity. All is good now, I filled it to the correct level, and did not find a leak, more than likely it’s a very slow seep, that might take over a year to leak back down.

 

Glad to see that it is fixed. It may take 10 years to leak down again. The AC compressor gets it's mechanical energy from the belt/pulley. There is a mechanical seal on the shaft that will leak over time. This is different from a refrigerator or house AC system which should not leak since they do not have a shaft seal.