A question for the AC geniuses...

I had my AC recharged last year after I completed my timing job (I had to discharge the system to get the valve cover off, etc). Normally I do all my own work - even the AC, but I didn't want to fuss with it at the time and wanted a full-blown professional service done. It's never had a pro shop charge it since I bought the truck so I figured what the hell.

Unfortunately the place that did my service did a ****-POOR job (long story). My AC did work after the service but when I went to use it for the firs time this year - HOT AIR and you can hear the AC clutch rapid cycling (classic low Freon symptom).

I hooked my AC gauges up today and sure enough it's low. I added 2 cans and the pump seems to be working right again (it's staying on and not rapid cycling). It also seems to be cooling although I have not did a full temperature test yet. It doesn't seem to get nearly as cold as it used to though.

Anyway...

My first thoughts were... where did all the Freon go? Obviously a leak somewhere. You'd think the AC shop would have checked for leaks and changed any bad O-rings - or they did and something else caused one, who knows. Maybe I tweaked something during the timing job and it took this long to show up. Again, another reason I wanted a full service done.

Working on the AC system is still a bit of a mystery to me and I'm learning. Problem is the hot weather is here and I still want a full and PROPER pro service done. A complete flush, orifice change, all new O-rings, the whole smash. This way it will give me a baseline for the future so I can take care of things on my own.

Question:

Since my truck's AC system is 19 years old and bone stock - would you recommend I replace the compressor, dryer and anything else before I take it to the shop? This way I can eliminate any potential (major) problems right off the get-go and it will no-doubt be cheaper than the AC shop if they find I need a new pump or other parts.

I don't have a problem buying new parts as they aren't terribly expensive. There are kits for around $200 - $250 that replaces the pump, dryer and all O-rings. Some even come with the condenser. I'm not sure (yet) which pumps to stay away from. I'm still researching. (Any input on this would be greatly appreciated).

Thoughts?

 

Find the leak first, that way you aren't blindly shotgunning the system. Once you KNOW where the leak is, then replace all the seals and o-rings as well as anything else at the same time if you want to. Otherwise, you may find yourself doing that job anyway after dropping considerable money only to find it still leaks, perhaps from some place that isn't a seal or o-ring.

Inject a UV dye charge into the system and run it for a while. Get a UV flashlight and yellow glasses (they help with seeing the dye under UV light).

 

Yep. I'm going to grab some dye today and see if I can find the leak. The only thing I took apart was the hose to the dryer so I could get to the right-side valve cover. Not sure where other areas might be prone to leaking. The Shrader valves are another culprit from what I've read.

Another question: How long can a person expect these 134 pumps to last? Yesterday's R12 pumps were built for interstellar battle but I don't know about the ones on our trucks today. As we've discovered - not all Ford parts today are like they used to be. My pump is still going for now but like many of us - you KNOW when it will finally fail... right when you need it the most!

So is my 20 year old pump and components... on borrowed time? Not sure, but as the old saying goes - it has fewer days ahead than it does behind.

I guess I'm overly-**** for preventative maintenance. I probably should have replaced it when I did the timing job. Not sure how much fun it will be to do it now. Certainly easier before the real hot weather gets here.

 

Did the shop that did the work last year offer a warranty? I'm wondering if they gave you a one-year warranty. If so I would take it back to them first.

If not, I agree with ProjectSHO89 to find the leak first. That is unless you're just fed up with working on it. If you are and you really want to replace everything ( except the evaporator) then I think you should get at least two quotes, from shops with good reputations, and try to get a 1 year or more warranty.

One more thing, I had my the original A/C compressor on my truck replaced last year because it would not pressurize the R134a. I had a local shop do it because although I've replaced compressors and other parts on other vehicles before, I didn't want to fool with it this time. Point is that if you're planning on keeping the truck for the foreseeable future, it’s probably a good idea to go ahead and get the compressor replaced, assuming it's the original one.

 

I plan to keep the truck until I can't drive anymore or the Earth has an extinction level event.. lol. It's paid off and I just put all that work into the timing job so it's staying with me or the family for the foreseeable future. The AC is all factory original.

I don't know if the shop had a warranty on the service. I didn't think about that. I'll have to dig up the paperwork. Problem is - I'm not so sure I want them opening my hood again to be perfectly honest. Would you?

Being that it's almost 20 years old - I think you're correct and it wouldn't be a bad idea to swap out the major components. I can install myself. This way it's a clean slate going forward. Surprisingly the parts aren't terribly expensive - even the OEM.

Which makes me wonder - just what is an OEM compressor these days? Who makes Ford's pumps? There's a slew of different brands but I'm betting they are all made by only a few places. My local parts house has a 'Four Seasons' kit as well as Amazon and Rock Auto. The reviews are decent. Any thoughts on their pumps and components? Which ones to avoid at all costs? I would prefer to stick with OEM when possible. The dryer is around $60. The OEM pumps vary.

 

The high side condenser lines are a common leak point
Same for the high side line to the evaporator
A visual inspection will find most leaks (inspect the condenser close and all the lines, hoses) (for oily residue)
After adding 2 cans of freon, you added freon on top of some air
That is most likely why the system performance is down a few degrees
I only use what would be more dye on the problem children
There has been dye in there from the factory since about 1995
Some claim the dye quits fluorescing after a short while
I can still see the stuff 20 years later
You did not specify what you are driving
Good luck
007

 

Oops. I thought I mentioned what I'm driving. It's a 2004 F150 Lariat 4x4. 5.4 Triton.

I picked up some dye and I'll give it a look soon as I can. Now that you mentioned it, there appears to be some oily residue near the pump - or at least at quick glance. The oily mess was there before my timing job as my timing cover had 2 holes chewed through it and tossed engine oil everywhere but after the timing job I cleaned up everything, replaced the cover and all new seals and gaskets - so there shouldn't be any residue from anywhere in that area. Maybe the pump is giving me a warning or one of the hoses near it.

Obviously a closer inspection is required. I'll put that dye in later in the evening so my UV light can see things easier. I'm blind enough as it is so having the sun down should help. Wish I had a garage big (and dark) enough, but I don't.

Thanks for all the replies! Nice to know we have people here that are specialists in the AC field.

 

Like i said, there is dye in there already
Take a look with the UV light and glasses now
The residual oil from any leak is a good indicator, and without a sniffer and it is what to kook for
The oil in yours will fluoresce with the UV (heat) lamp
I can see the dye better without the glasses

 

UPDATE:

Before I put in the (new) shot of dye a little bit ago, I looked all around with the UV light and the front of my pump DOES have a green dusting on it. The green 'dust' is all around the clutch/pulley area like someone took an airbrush to it with fluorescent green paint.

I put in a shot of fresh dye and ran it for about 10 minutes and have NOT seen any fresh signs of it but then again the pump won't stay engaged long enough to really circulate - or at least that's what I'm guessing. The only other place I see the fresh dye is a few dribbles at the charge port where I put it in but that's expected.

I cannot see any dye new or old anywhere else... at least not yet. I have to run to the store so maybe a shakedown cruise will give the dye more time to pump around.

So... is my original hypothesis correct and I should go ahead and replace the (almost) 20 year old pump and dryer? I think it just gave me a huge red-flag warning to do so!
I had the pump engaging fine yesterday after I put in a few cans of Freon but this morning it's right back to rapid-cycling. Perhaps it has just enough pressure left in to engage the pressure switch but not enough to keep it on. Any higher pressure overwhelms the bad pump seal maybe?

Something turned the pump pulley into Hulk green and it wasn't anything I did on the timing job. There's no other leak anywhere. I'm a stickler for leaks! Can't stand them. OCD in fact.. lol.

I do recall the sniffers you're talking about. My Dad used to work in/on appliance refrigeration and I remember him having one of them. He once told me they could detect Freon your eyes can't see especially on older systems that naturally weeped out. Apparently those old refrigerators and freezers often gave a false reading even though technically there wasn't any leaks.. Neat little devices. Unfortunately I don't have his anymore. Or even if I do... it was made around the same time the Earth was still cooling so I doubt it would be reliable.

Thanks again! I think this nut is about to be cracked and another one of the automotive mysteries under my belt!

 

i think more important than looking for a leak with the green dye is seeing whether the system will hold deep vacuum for at least 24 hrs.

even though i do just about all the work on my vehicles myself, prior to a couple of years ago i had no experience working with a/c systems. so when my 04 f-150 started blowing "cool-ish", and not ice cold - and the compressor started to cycle more rapidly than before - i took it to a professional shop figuring they might just do a recharge. well, like most places, they tried to upsell me unnecessarily by saying, "look there is a leak on the manifold hose assembly, see the green dye here? you're gonna need a new one. $450 plus labor" i said eff that, told them to just suck the system down and i'll be on my way. i knew that even if there was a leak, it couldn't be that bad because the a/c still worked... it just wasn't as ice cold as before.

so i went to o'reillys and rented a manifold and vacuum pump, did a little research, and pulled a vacuum on the system. it held for 2 days. yeah... suuure there's a leak buddy.

so then i went back to o'reillys, bought a couple of cans of r134 and a little pag oil, and charged the system to spec. it worked great. that was about a year and a half ago, and the a/c STILL blows ice-cold.

so, long story short i wouldn't go replacing things just for the hell of it, i would try to get the system to work with what you got, and only replace what you actually need. best of luck with it!