cliffs: bad compressor.

Never was happy with the performance of the system, but now that the temps are hoovering into 100s it gets bad.

Basically the performance is acceptable when you are moving, but when you stop the ac just about fails. It still produces cool air, but not anywhere as cold as needed. It feels cold right at the vents, but a few inches out it really isnt. Dont have a IR thermometer handy but it doesnt matter, because i can feel it isnt as cold as it has to be.

After being stuck at a drive through for 10 minutes sweating and cooking myself earlier today, it has to get fixed, somehow.

I have rear air, that works fine. well as good as the forward air anyway. Freon is just fine, fans all work as they should at least visually. no clogs in the system or confused hot/cold zones. no electrical gremlins that i can tell of either.

compressor is rather quiet when on, you really don't even hear/feel it, but it cycles as you would expect based on settings. i drain enough condensation water to fill the titanic and sink it. going by that alone you would think it is working awesome, right?

So, now that you have all the info i can think of, is crappy cooling efficiency normal with these or is my compressor just done for and not able to cool?

 

Don't need IR, a regular utility thermometer with a metal "nail" sticking out the back will poke in the center vents just fine. Outlet temps can be 42 - 44 degrees. Home Depot has Ryobi IRs for $29. But in your case it is probably time to check with guages. The calibrated Mark I palm reader can't tell you if head pressure is low, high, etc. Of course the front condenser (AC radiator) needs to be clean of trash, the electric fan(s) in front of it need to be functioning, and blowing the correct direction (toward the engine).

May be time to have it vacced down, check for leaks, refill to proper levels with refrigerant. You have described "low" AC charge. What made it low is another matter.

 

i might pop the line and drain it but that will cause it to evacuate some oil which means i might as well drop the compressor. and if i do that i might as well change it. 360$ part before tax and then all the supplies + dryer. looking at 500 DIY when all is said and done. so you see why i want to avoid opening up the system.

last time i tended to it was back in early may. no change in performance since then or after my tending to it with some extra freon (almost didnt take any). i'll check it this morning and see if any has come out. but it really goes with engine temp. if you crank it and stationary with cool engine/open hood, it's fine. Funny because no matter what the coolant temp won't go over 208F so i know it is within LR specs. you would think it would be designed to deal with that ambient. PS. 200F normal stop and go temp, 195 cruising temp. 208 is as high as it gets and thats baking in the same spot for a while. And it seems once it hits 203 the ac really begins to degrade.

any way of testing fan rpm? wondering if its heatsoaking the condenser

 

AC shops seem to be able to vac down and replace refrigerant without pulling compressor, with recovery machines designed for such. You may have air in your system in addition the refrigerant.

Harbort Freight and others sell photo tachometers, you put a tiny piece of reflective tape on the rotating part and it reads it.

 

have someone pull a vacuum and recharge the system, there is no need to remove the compressor or replace the drier. you only need to replace the drier if the system has been open to the atmosphere for a prolonger length of time.

 

How do you know your freon is at the proper level, do you have a set of gauges or are you guessing?
My money is on low freon which can easily be recharged with out going to a shop.

 

And Harbor Freight (not a stock holder) has gauges for $49 and a vac pump for $99, and a 20% off coupon on their latest flyer. Of course, AC tools don't have much use in other places on the truck, but when you have a pasture full of oldies like I do you'll need it from time to time.

 

The system does not need to be pulled down, freon does not wear out, all you have to do is buy a large can of 134 with oil and fill till the gauge indicates you are at the proper pressure.

 

With 100 degree temps you are only going to get a 40 deg drop in temps max. So your only going to be blowing around 60 deg at the vents. Remember your driving a vehicle with windows like a green house it's getting some serious solar gain. Bottom line, you are going to need to put some gauges on it to verify freon pressure, probably need to be above 50psi at idle. Just blindly adding freon can cause problems, too much freon and performance will plummet.

 

As what everyone mentioned, the system needs to be gauged. Normal temp failure at idle is the condenser fan, but you mentioned that they are working. I would bet the system does not have enough freon.

I had the same issue with one of my RX7s years ago. I thought it was one of the components, but after gauging the system, it came down to not enough freon.