Awesome. Thanks for all the feedback guys!

The condenser is squeaky clean. That was one of my first fixes.

If the fan clutch was going bad I'd expect the car to run a little hot and it doesn't. (not ruling that out but I don't think its likely). At the moment I'm leaning towards it being the blend door stuck open a fraction or the evaporator being clogged. Maybe some leaves got in or whatever.

Tonight I'll check those evaporator temps. Maybe Autozone has some loaner gauges...... I'm such a cheapskate!!!

I'm also going to mess with the heater and see how opening the blend door affects the vent temperatures. If the AC gets hotter the longer the car stays on that's got to be the blend door.


Here's hoping the dashboard doesnt have to come out. I've done that before............

 

No, you wouldn't notice the difference.

If you can clamp off one of the heater hoses, you can quickly determine if the blend door is at issue or not.

 

I finally had a chance to measure the temperatures today. Apologies for leaving this blank for a week.

I ran the truck for 15 minutes. Same test as before, all the windows open and max AC, max airflow

Ambient temp = 90F
Vent temp = 69F
Pre-evaporator temp = 57F
Post evaporator temp = 60F (Just before the drier)
Temp before compressor = 64F
Temp after compressor = 143F
Temp after condenser = 120F


It looks to me like the evaporator isn't doing a very good job.......

I look forward to hearing what you guys think.

 

It's not the evaporator's fault the inlet is only 57F.

We sure could use some accurate pressures...

In their absence, I'd recover, back flush the condenser, replace the orifice tube (inspect for junk first), evacuate, and recharge by weight.

 

I'm in agreement and will also say it's low on an R-134a charge.

 

Well, I suspect its overcharged, if it's anything related to the charge level. Might be a restricted orifice tube or condenser, or a faulty fan clutch. Unfortunately, the data are suspect, so it's tough to be more comfortable with an opinion..

 

Are the evap. temps the refrigerant lines going into and out of the evap?

 

I think you have an orifice tube problem. Did your a/c work good last year? If it did, did you add any freon this year?

 

Did you check your blend door?

 

Over charge... Also, if your checking temp with the A/C on Max and have the windows and a door open you are defeating the Max setting purpose since you are not cooling the cool air in the vehicle, you are trying to cool outside air. Just like using the "norm" A/C setting. My problem in my 99 was cured when the system was vac'd and recharged, correcting the overcharge issue the DIY previous owner caused by recharging the system himself.

 

Well thanks to everyone for their responses. This is the BEST forum!

Given the lack of love for my harbor freight gauges, and the fact that I can't recover the R134a myself I'm plannign to take the car to a local shop for them to recover the freon, and I'll see if they're willing to hoook up their gauges and give me a diagnosis first.

After that my plan is to replace the orifice tube and drier, back flush the condensor, evaporator etc and re-charge.


I'll report back in a week or so........ Hopefully with good news!!

 

If you're going to go that route, let them make the diagnosis. Otherwise, if you simply tell them what to do, that's what they'll do and will pass on any liability of the named procedures don't resolve the issue.

 

It took a little longer to wrap this up than I hoped. I've been on vacation and then it cooled down a bit and I got lazy blah blah blah. You know the story.

Anyway:
- Replaced the orifice tube with a variable orifice tube (supposedly work better when the engine is idling)
- Replaced accumulator
- Replaced all the o-rings
- Back flushed the condenser

The system held vacuum first time and I added 64oz of R134a.

It blows noticeably colder when you first turn the AC on, but I haven't had a very hot day to see how it handles 100+ ambient temperatures, but when its 80 outside I'm getting 52-55 out of the vents which is a big improvement.


So thanks again everyone for all your help!!

I'll report again once we have a really hot day.

 

It should be down closer to 40.

 

Ooops I meant 42-45F.

Here is a picture of the old krusty orifice tube

https://picasaweb.google.com/1018131...02606294068322