AC Sanity Check

[C420sailor]

Pretty sure I know what’s going on, but I love bouncing things off you experts first.

‘99 5.0 EB, 131k. Bought it in late 2019, and the AC has always been weak. Good flow, but not really cold air. I threw gauges on it a while back and while I can’t remember the exact numbers, I remember low side being good but high side being high.

Turned the AC on for the first time this season, felt mildly cool air, but didn’t notice any RPM dip…normally you can feel and hear the compressor kicking on and off, and the idle shifts a bit. Nada. Popped the hood to see the clutch short cycling. On for 1-2 seconds, off for 1-2 seconds, repeat. Almost seems like the compressor isn’t pumping, as there is no indication of increased engine load when it kicks on.

Traditional logic is low refrigerant charge, but this is my first EATC truck and that thing is foreign to me. I won’t be able to get gauges on it for another month or so, as they’re a few states away.

Any other possibilities?

 

[Chris1973]

Pretty sure I know what’s going on, but I love bouncing things off you experts first.

‘99 5.0 EB, 131k. Bought it in late 2019, and the AC has always been weak. Good flow, but not really cold air. I threw gauges on it a while back and while I can’t remember the exact numbers, I remember low side being good but high side being high.

Turned the AC on for the first time this season, felt mildly cool air, but didn’t notice any RPM dip…normally you can feel and hear the compressor kicking on and off, and the idle shifts a bit. Nada. Popped the hood to see the clutch short cycling. On for 1-2 seconds, off for 1-2 seconds, repeat. Almost seems like the compressor isn’t pumping, as there is no indication of increased engine load when it kicks on.

Traditional logic is low refrigerant charge, but this is my first EATC truck and that thing is foreign to me. I won’t be able to get gauges on it for another month or so, as they’re a few states away.

Any other possibilities?

If the compresser kicks on and off it's low frion.had the same issue in mine.had a new compresser installed and the front added to the right pressure and it worked perfectly for awhile then your problem happened.had a small leak.so I just added more friends and it's working now.will fix the leak when I have the time.

 

[Pete Deering]

If the compresser kicks on and off it's low frion.had the same issue in mine.had a new compresser installed and the front added to the right pressure and it worked perfectly for awhile then your problem happened.had a small leak.so I just added more friends and it's working now.will fix the leak when I have the time.

Chris, just a note: as you lose Freon, you also lose ac oil. the compressor will start to become louder.

 

[Chris1973]

Chris, just a note: as you lose Freon, you also lose ac oil. the compressor will start to become louder.

Just saw your reply to the when it leaves free on at least the compressor oil. I did know that and did put a put it in the system oil plus the the red dye to find the leak so it it has been oiled but thank you for that

 

[C420sailor]

Doing this in a couple days…tired of sweating through my clothes lol.

Took a peek and it looks like the EGR tube is cracked at the flexible section. I think it’ll be much easier to change with the drier removed, but the replacements all get terrible reviews for not having a flexible section. Hmmm

I wonder if I can braze/weld it shut…?

 

[Turdle]

The " flexible area" really isn't much flexible. New tube may need adjusting to fit, but, hard part really will be getting old one off. Might need to cut end off large wrench to allow a cheater pipe to slide on.

 

[Pete Deering]

Just saw your reply to the when it leaves free on at least the compressor oil. I did know that and did put a put it in the system oil plus the the red dye to find the leak so it it has been oiled but thank you for that

Just a note for the DYE just uses a few drops.

 

[C420sailor]

Okay, if I can get it off cleanly, I’ll try to TIG it up with some 309 rod

 

[Mbrooks420]

Okay, if I can get it off cleanly, I’ll try to TIG it up with some 309 rod

Getting it off is a real bear. I ended up replacing the whole manifold. Gabbing up a new one wouldn’t be hard if you can get the large thread off.

 

[C420sailor]

Can one of you fine gentlemen with a 99ish 5.0L tell me what the charge/PAG oil capacity is? My truck has a 4.0 SOHC front end, so I have all 4.0 stickers under the hood

 

[Chris1973]

Just a note for the DYE just uses a few drops.

Ok.thank you.

Can one of you fine gentlemen with a 99ish 5.0L tell me what the charge/PAG oil capacity is? My truck has a 4.0 SOHC front end, so I have all 4.0 stickers under the hood

7 oz

 

[C420sailor]

And another question. Sorry guys, AC isn’t my strong suit.

Anyone know how many o-rings go between the accumulator and evaporator at the threaded fitting? Whatever was there was mangled when I took it apart, so I have no idea what goes in that joint or how many

 

[Pete Deering]

And another question. Sorry guys, AC isn’t my strong suit.

Anyone know how many o-rings go between the accumulator and evaporator at the threaded fitting? Whatever was there was mangled when I took it apart, so I have no idea what goes in that joint or how many

Buy a O-Ring set ( Bag) AutoZone or any of others part Store sells them for your car. the lower connection of the EVAP is a small O-Ring. Matchup ID of the O-Ring with the OD of the pipe. If O-Ring is too large you will not be able to slip the connection together(IN). For the accumulator matchup ID of the O-Ring with the OD of the flare fitting seat. One O-Ring each for each connection. Place the O-Ring in the PAG oil before installing. I uses a shot glass ( 2oz) It has oz marked on them.Wal-Mart sell them they also have 4 oz shot glass or measuring cup.

 

[Pete Deering]

And another question. Sorry guys, AC isn’t my strong suit.

Anyone know how many o-rings go between the accumulator and evaporator at the threaded fitting? Whatever was there was mangled when I took it apart, so I have no idea what goes in that joint or how many

aren't you using a new accumulator it comes with o-rings

 

[C420sailor]

My new accumulator came with o-rings, but it only came with four---three large and one smaller. And the Ford FSM mentioned that connections either use two or three o-rings...so that confused me.

I ended up finding a video of a guy doing a Ranger system, and he clearly used one o-ring at the threaded connection, so that's what I did. Looks like it was the right call.
I just wrapped up. Replaced the compressor, lines, condenser, orifice tube, and accumulator. Everything but the evap. I gave it a good flush with a flush gun. Added the PAG oil and buttoned her up.
I'll vacuum her down tomorrow morning and charge her up. Hoping for some cold air!
Thanks guys

 

[C420sailor]

Done!

So the final verdict was that the system was very low on refrigerant. Between the leak and the noises the compressor made, I elected to rebuild the system anyway.

Did compressor, lines, condenser, orifice tube, accumulator. Flushed and cleaned the original evaporator.

Put in 9oz PAG, pulled a vacuum for 75 minutes, charged with 30oz of 134. Pressures were perfect.

She now blows COLD.

Thanks to everyone here, and especially @donalds for his excellent AC thread.