My 2005 5,4 XT blows cool air only. I've read many threads, but am trying to approach this in steps.

Air on max blows 65 degrees at the vent. I've charged the system twice because the low side indicated low pressure. After charging, the temp is 45 degrees.

I've used dye but did not detect a leak. I used maybe a third of a can of stop leak to no avail.

The compressor is cycling OK, I think.

Is there a thermostat that is limiting the temperature? Where is the cabin filter and is it easy to access?

Thanks for the help.
Oldforddy

 

You may need pro help . Ac work is not easy to fix . You have an orifice tube that creates the spray in the evaporator to provide cooling . In that there are filter screens that can get clogged from debris breaking loose . At one point you have to get help as the parts are expensive and cheap ones don't always work .You have to change dryer anytime you do parts replacement or system exposed to outside air . getting air into system causes ice crystals and corrosion .There is a lot more to it to get a lasting fix .
I have replaced condensers ,evaporators ,oriface tubes ,dryers ,compressors .lines etc . I have a vacuum pump and gauges but still its hard to find a small leak .

 

Your blend door might not be going all the way over to the cold side, or it sounds like you do have a leak and are having trouble detecting it.

 

why are you worried about the thermostat and cabin filter ? When properly filled, you get 45 degrees outlet.. That's GREAT !... how often do you add a can ? Once a year ? once a month ? I have a 2002 EXPLORER that needs a can every year just before summer... So what ! Cant find a very small leak and $6. year aint much.

 

Thanks for the responses. I've only had the truck six months, 150K)

It's 45 degrees when I charge it, but the next day, it's back to 65 degrees. I intend to search out the leak - I have a R134 detector and can use ultra violet dye again.

I'm assuming the leak is small & ask about a cut-off because it blows cool. I'll use some stop leak also.

I'm searching how to check the cabin filter and other filters at the same time.

Thanks again,
OLDFORDDY (81 F150 Ranger, 88 F250 XLT Lariat, 05 F150 5.4 XL)

 

If it looses a can or charge overnight, you should be able to find it.... the dye might work... just a soapy water bottle sprayed on things might show up.

 

you should be monitoring the suction side PSI also... that tells a lot..... When motor is off, you get 90-100 psi on LOW and HI side as it balances out... When you start the compressor it will pump down to 25 psi, kick off, build up to 45 psi, then kick back in... It should stay running for 30-40 seconds, then off for 10 seconds, etc......... If it does not stay kicked in for more than 10-15 seconds, your low on charge gas.

 

Thanks again. Very helpful. I'll put the gauges on it and search for the leak. Good info on the compressor action.

I noticed the suction side really, really hot when I was charging it last time.

Oldforddy

 

The really, really hot side was the discharge.

Suggest taking it to someone who knows how the system works.

 

The stop leak contaminated the system. To fix it properly you need to replace the compressor, condenser, orifice, accumulator, flush the evaporator, and any rubber line with a muffler. The system came with dye from the factory so adding more does more harm than good. Too much dye causes to oil to lose its lubricity. Since you can't locate the leak its more than likely the evaporator.

 

Thanks for all the help. Appreciate it very much. I'll keep everybody posted.

Oldforddy,
Gainesville, FL

 

I've done nothing on my ac but today it was blowing 55-60 degrees and keep the truck cool in 90 degree weather.

The only difference is I shut the passenger side dash vents and have the selection on floor and dash. Before I paid no attention to the flow.

I can't tell if the compressor is performing differently.

Go figure.

 

Not too bad for a 14 year old truck... My 2002 EXP puts out about the same.