A/C System lasted about a week and is now acting like it is low on charge?

TF43

MEMBER
2010 FORD EXPLORER SPORT TRAC
4.0L
V6
2WD
AUTOMATIC
85,000 MILES

Am a bit stumped by this Sport Trac I had to change both Schrader valves on the service ports... High and suction side. Pulled the system down to with a vacuum pump to minus microns far as the gauge goes past zero... And pulled the vacuum for a good 30 minutes. Turn the pump off and it held vacuum for well over 45 minutes. No signs of leaks from any other component in the system. Charged it, and never had head pressure over 240, but suction pressure was sort of funny in reading on the gauge. Reading the 134A scale, if was looking at it right was around 10 pounds, but the thing was blowing ice cold. It has lasted about a week and is now acting like it is low on charge again. Haven’t put the gauges back on just yet, but am wondering if I might have a sticky TX valve...?
Thanks for any input and or idea's
Terry

5 Replies

KEN L

MASTER CERTIFIED MECHANIC
42,973 POSTS

It does sound like the expansion valve needs to be replaced. Also, I have seen A/C systems hold their vacuum while not running and then lose the charge after the recharge because the front seal of the A/C compressor is leaking, I would like for compressor oil at the bottom of the compressor to confirm the failure. Another way to change is to charge the system and use a sniffer to check the front of the compressor. This guide can help, and I have the location and instructions on how to change out the expansion valve:

https://www.2carpros.com/articles/air-conditioner-leak-detection

This video can help as well:

https://youtu.be/4EqdrBVb0sY?si=GzUkeQJsJBmwIzRA

Check out the images (below). Let us know how it goes/

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Monday, November 27th, 2023 AT 3:07 PM

TF43

MEMBER
93 POSTS

Thank you, Ken. It held for about a week and I took it back over to my tech with his sniffer and found the Schrader valves were still leaking, go figure, cheap replacement valves. Ordered some OEM type valves and will replace next go around when it is not blowing cold again. In the meantime, he tapped on the pipes some and the valves finally closed up.
I just received my 2nd sniffer in the mail yesterday (1st one I had I lent to a different friend and his kids got a hold of it. LOL) Anyway, minor detection but it reads the same when checking inside the plastic caps. So, appears okay for now, and it's been about 3 weeks.
Thanks again

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Saturday, December 23rd, 2023 AT 1:47 PM

KEN L

MASTER CERTIFIED MECHANIC
42,973 POSTS

Nice, I have seen the caps hold the pressure so as long as they are in place and tight you might be okay, thanks for getting back to us.

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Tuesday, December 26th, 2023 AT 9:28 AM

TF43

MEMBER
93 POSTS

Hi Ken / Joe,

I'm ready to install a replacement compressor, and filter/dryer but am getting mixed information on the capacity of Pag 46 oil it should have in it. 2010 Sport Trac 4.0 2WD no rear A/C.
It ships with 3oz installed, but naturally will drain that and start with fresh oil.
I read anywhere from 7 to 9oz Pag Oil?

And I get mixed information of filling; pour it all in the compressor, or add some to compressor, then condenser, filter dryer, evap, etc. If one pours it all in the compressor and starts it up it may damage the compressor?

And I plan on putting in some oil and letting it sit on the clutch end for a few minutes to get some oil around the seal to help lube it before startup.

I'm sure it is okay to add the oil at the start, then pull my vacuum on the system before recharge, and oil lost during vacuum is minimal?

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Monday, April 8th, 2024 AT 9:55 PM

KEN L

MASTER CERTIFIED MECHANIC
42,973 POSTS

Yes, add the oil before the vacuum stage, here is the PAG oil capacity:

266 ml - (9 fl oz) (vehicles without auxiliary systems)

Let us know if you need anything else.