I have a F150xl w/ 4.6L & 2x4. It's got about 188,000 miles on it. I bought the truck brand new from the dealership in 2006. I am religious on my oil changes and never really had a problem with the truck until now. After I have been in the truck for about an hour or so the AC will blow from cold to hot. It still has the original OEM AC system in. Is my AC compressor going bad?

I'm not a mechanic so I really don't know where to look.

 

Impossible to answer. Insufficient information.

Well, I'd suggest starting with the HVAC FAQs, link is in my signature. While written for the previous generation, it still applies to the newer models with the provision that you do have a PCM-controlled HVAC system.

 

Hello -

I don't want to piggyback on this thread I'd like to create a thread dedicated to my issue.

projectSHO89 - I read your HVAC FAQs. You appear to be an HVAC guru - what is the most appropriate sub-forum for me to create a thread related to my issue (below)?

2003 Ford F250 6L (early build), 188K miles, belt drive (serpentine belt) broke into x2 pieces. Removed radiator/fan shroud, removed fan diffuser shroud, removed both smooth serpentine belt drive pulley & grooved serpentine belt drive pulley, removed belt drive tensioner (each of those items have been ordered & each has arrived). Upon further evaluation, I suspect the AC compressor is the cause of the broken serpentine belt - e.g. the AC compressor pulley/clutch is frozen, locked, baked, toast i.e. won't budge. Cleaned the remaining bits/pieces of rubber from crank pulley, etc., etc. - most of which I wore for a considerable time yesterday until a hot shower resolved the issue. I have reviewed what it takes to remove this beastly AC compressor - I intend to R&R the required ancillary components while I have the system apart e.g. accumulator, evap. core, drier, etc., etc. (I don't plan to have to open this HVAC up again for any reason in the next 100K miles).

I know how to read, think, & follow directions - automotive HVAC is "not" my forte - in fact, it's far removed from my automotive knowledge base. I own a '71 Oldsmobile Cutlass Supreme (I perform all the maintenance, e.g. pulled the engine, changed out "stuff") & an Indian Chief Vintage motorcycle - I can do "stuff". What I don't understand and what I don't know is automotive HVAC. I'm digressing - I said I wouldn't piggyback this thread....

What sub-forum is the best place for me to create a thread pertaining to my issue?

Thanks!
Norm

 

The one that covers your truck will get the widest exposure.

FWIW, a lot of times you only need the pulley and hub and can repair the system without tearing everything apart. The pulley bearing collapses and locks everything up and the compressor is still good. You'll have to remove the hub and pulley to see if the compressor shaft still works.

 

Much appreciated...

 

Doesn't sound like a typical compressor or clutch failure since it will work for an extended time and then fail. I have an '07 with 4.2L manual. Sometimes on a hot day when re-starting after a hot soak, the compressor will not activate for a minute or two. Otherwise, works fine. Whatever causes that may be the same thing that causes yours to not work sometimes. I used to play with the old Freon systems and didn't mind charging it up every year. Well, I got pretty good at giving the AC a good environment in which to excel. There are several things to do to see if anything helps. The most obvious one is to look at the front of the compressor and see it its oily. If so, it is leaking refrigerant along with its oil, so that is something to consider. Next is to check the drive belt and see if its slipping. Next, clean the radiator and AC condenser - I just mentioned the radiator because you can't clean the condenser without cleaning it too. Now with it running, check the larger return line at the compressor (suction line) to see if it is cold and sweating/frosting. If it is not cold enough to sweat, this could also point to low refrigerant. Also, with low refrigerant, it will quickly cycle off and on.
Now inside the cab, how's the air flow from the registers? Does 'Max Cool' close the door for internal circulation only? Does your model truck have a cabin air filter? If so, is it fresh? If you have certain conditions, the evaporator can ice up and stop the air flow as well as the compressor. Then after it all melts, everything works again. You could have a blockage in the cabin air intake under the cowl screen, like maybe a mummified squirrel.
As you can see, even as a layman, I can think of quite a number of things to do before you start thinking about buying anything. I'm not going to mention adding some refrigerant because everybody will get their dander up and start preaching about how wrong it is, but if you gave it a little until the suction line gets cold, it'll probably get you through the summer.

 

That's actually a symptom of an excessive clutch gap. As the components heat up from operation, the magnetic field of the clutch coil isn't strong enough to maintain a positive engagement or to re-engage when commanded.