96 F150 A/C Q

[sleddriver]

I noticed the evaporator is in the engine compartment along with the blower motor. Anyone gotten in there before to clean both the squirrel cage & evap. coil? Does the A/C system need to be evac'd first?

Airflow is quite poor with fan on Max, while sitting still in traffic. I'm thinking it all needs a good clean along with the blower motor re-lub'd.

What say you?

 

[Chris142]

Yes you must evac the system.then you can pull the whole box out then pull the evap out of it.dont waste your time trying to split the case in the truck.

 

[punisher]

Pull the fan first, look at it, see how much garbage/hair/dust is on it. See if you can access the evap core after you pull the blower motor/squirrel cage out. I think on those you can at least see the evap core with the motor out (small mirror). You might very well be able to get a shop vac hose in there to pull some of the crud off the core (assuming it has crud buildup).

I did one of those many years ago and don't remember it being particularly easy. Not near as bad as replacing an evap in a Navigator though.

 

[sleddriver]

Thanks guys. I'll pull the fan first. No telling what's on the outdoor-side of the evap. But it looks like there's no access to that area, short of pulling the evap.

 

[punisher]

I just looked at a youtube video and you might be able to pull off the resistor assembly (2 8mm bolts) and use a flashlight to look at the core. Just a thought.

 

[sleddriver]

^^^ OK, that'll still be downstream of the evap. Did Ford make no provision to cleaning out the air intake vents running from side-to-side? Seems over time a bunch of leaves, twigs, etc has fallen in there. Any way to remove it?

 

[punisher]

You are correct, the video showed the evap housing from the wrong year, my bad.

Some pull off the passenger side vent intake cover at the cowl and put a piece of screen over the air intake to keep some of the garbage out. I even recall one recall for Mercury villagers where we had to put on a screen over the outside air intake in the cowl because so much garbage got sucked into the blower/evap case that the blower resistors would ignite the debris.

 

[sleddriver]

How do I pull off the "passenger side vent intake cover"? I didn't see a way into this at all. There is a slotted metal piece between the lower edge of the windshield and the opening to the engine bay. It looks like one continuous piece, part of the body sheet metal.

I did a YT video search...which one were you looking at?

 

[sleddriver]

I pulled the blower and found a lot of leaves downstream. Sucked those out. The 'clean' side of the evap is really dirty. The other side must be really bad. I'm going to shoot some Al-safe degreaser in there, then back-flush with a strong water jet. About all I can do w/o access to the other side.

I noticed there is a vac motor nearby with a rotted vac line. Unable to find where it connects to. Perhaps this is the RECIRC or MAX door. Right now it's non-functional so there is no MAX A/C setting.

More later...

 

[TFB1]

Originally Posted By: sleddriver
I pulled the blower and found a lot of leaves downstream. Sucked those out. The 'clean' side of the evap is really dirty. The other side must be really bad. I'm going to shoot some Al-safe degreaser in there, then back-flush with a strong water jet. About all I can do w/o access to the other side.

I noticed there is a vac motor nearby with a rotted vac line. Unable to find where it connects to. Perhaps this is the RECIRC or MAX door. Right now it's non-functional so there is no MAX A/C setting.

More later...


The vac line should exit from the wiring harness, had to cut tape on harness of my '93 to access fresh tubing...

If you can't locate it I can take a pict of line on my '96 F-150...

Constantly using the normal position(fresh air into evap) will eventually plug them up... Just last week a friend replaced a evap in a Econoline because it'd been operated in a dusty area, looked almost like it was coated with plaster...

 

[sleddriver]

Thanks. I did find the other end last night. Peeled back the tape to get to a newer section, then reconnected them using some silicone vac line. The RECIRC door now closes when activated.

The degreaser worked really well at restoring the evap back to shiny aluminum. I realized that I WAS looking at the outdoor-air side of it! The dirt was so embedded on the blower cage I had to use a small bottle brush and scrub each individual blade to clean it. Looks like new now.

I went for a short drive, then stuck a thermometer in a dash vent. It was only cooling to 66°F. On MAX, it dropped to 60°. The suction line was sweating heavily. I added about 1/2 can of 134a, but noticed no difference. Outside temp ~ 100°, so that's a 40° delta-T. However my 98 wagon will blow ~ 44°. Could still be undercharged or something else is going on. Air CFM out the vents is like NEW!

 

[sleddriver]

Been doing some research on Ford's. Lots of complaints about "A/C not cold enough." Since this truck is so old and not mine, I've narrowed it to:

• Engine fan isn't pulling enough air through condenser at idle or low speed. Could be the fan clutch is slipping. I can test by spraying the condenser with water at idle and/or using a big shop fan directly in front.
• Condenser is partially clogged with bugs & dirt.
• I noticed the fresh air door isn't quite closing all the way.

Looking forward to trying this out.

 

[SteveSRT8]

IME here with GM trucks the first noticeable symptom of fan clutch wear is poor AC performance at idle.

Definitely easy to check and cheap to fix....

 

[TFB1]

Assuming it has enough charge that compressor isn't constantly cycling, I'd bet on fan clutch as well.. My old '96 with 185K mi cools fine, dunno average life of fan clutch...

 

[Chris142]

Fan clutch is easy to check. Start it and see how much air it pulls

 

[sleddriver]

Thanks for the replies guys! I need some education on testing a slipping fan clutch. Never owned a car with one. To test the draw through the condenser, I thought of using smoke and to see if it would hold a sheet of paper to it.

How do you guys do it?

 

[sleddriver]

UPDATE

Worked some more on it today. Made lots of notes & measurements. I don't have any gauges for 134a, nor did my neighbor.

Thoroughly sprayed the condenser with an alkaline detergent, waitited 10min. then flushed with lots of water and blew out as much water as possible with electric leaf blower before proceeding.

Discovered the fan blade/clutch wobbles a bit when wiggled. I stuck a sheet of paper on the front of the condenser with the motor running and there was enough suction to hold it in place, but lightly.

Fan would only turn about 60° when spun by hand when clutch was ~ 110°F.

Air vent temp with fan on 2/4, outside air, no A/C: 88°F
A/C on NORM. Air vent temp after 30s................80
A/C on NORM. Air vent temp after 60s................76
A/C on NORM. Air vent temp after 120s...............68
A/C on NORM. Air vent temp after 180s...............68
A/C on MAX. Air vent temp after 60s..................66

This is odd...yesterday it cooled to 60 on MAX. I checked the RECIRC door and it was OPEN! Vac motor unenergized. So I played with the vac hose and all the sudden it began to close. There must be a leak in the old rubber elbow. I was reluctant to reach in there & pull it off because I thought it would rip. After being sure the door was CLOSED, I let it run for 5min and the temp had dropped to 60. So we're getting a 28° delta-T across the coil. A bit weak for a truck.

Suction line temp = 60°.
Liquid line temp = 117°

So that's as good as I can get it. Didn't go on a HWY test yet.