AC Info

[dboyw]

Question about air conditioning in the truck. It just does not feel as cool this year. I have the ac mod to shut off the heater. I added 134a with stop leak and it made it better, but still not icy. I need to run max cool to feel good.

1. Should the compressor turn on and off for three seconds at a time? That's how it run, 3 on, 3 off, 3 on, 3 off.

2. What else should I look at or do to make it better?

Thanks for the help.

 

[JLDickmon]

Question about air conditioning in the truck. It just does not feel as cool this year. I have the ac mod to shut off the heater. I added 134a with stop leak and it made it better, but still not icy. I need to run max cool to feel good.

1. Should the compressor turn on and off for three seconds at a time? That's how it run, 3 on, 3 off, 3 on, 3 off.
2. What else should I look at or do to make it better?

Thanks for the help.

it's still low on charge.
it should have a 15-20 second "on" time

 

[02SilverStroke]

I'm having AC problems too. A few weeks ago mine started blowing warm air occasionally (with max air and coldest setting). Took it to local Firestone store, they said it was 2 pounds low on Freon (first time to add since new in 2002). Couple of days later, still blowing hot and cold air, took it back, and they said it could be the compressor or evaporator going out. Lately I've noticed that when the engine is running at 1500-2000 rpms, blows cold air most of time. However when engine is below 1500 rpms, and especially idling at stop lights, it blows hot, but when the engine gets back up to 1500+ RPMS, blows cold again. Any suggestions/ideas? I probably should take it to an AC shop.

 

[JLDickmon]

I'm having AC problems too. A few weeks ago mine started blowing warm air occasionally (with max air and coldest setting). Took it to local Firestone store, they said it was 2 pounds low on Freon (first time to add since new in 2002). Couple of days later, still blowing hot and cold air, took it back, and they said it could be the compressor or evaporator going out. Lately I've noticed that when the engine is running at 1500-2000 rpms, blows cold air most of time. However when engine is below 1500 rpms, and especially idling at stop lights, it blows hot, but when the engine gets back up to 1500+ RPMS, blows cold again. Any suggestions/ideas? I probably should take it to an AC shop.

hose down the condensor (a/c radiator on front of truck) and see if it improves..

got a couple scenarios this might be, so I need a tad more information..

while you're hosing off the condensor, time the compressor cycle as well

 

[Gus Johnson Ford]

Have you checked your pressure cycle switch? I'm not a tech, just a parts manager, but that is often times a problem.
Just a thought, like I said, I don't work on them, just sell the parts to those that do.
Chuck

 

[PHXF250]

My Advice, I assume you have no pressure gauges, refrigerant sniffer of other A/C equipment, I assume you are low on freon as you seen an improvement after charging your system with R134 so, Go to a good trustworthy shop and have them Vacuum and fully recharge your A/C system and install leak detection Dye.

One reason you are not experiencing a complete improvement on you ability to cool your trucks interior is because you cannot fully charge an A/C system without a good 10 or 15 min of Vacuum then recharging it to factory specs in Pounds of R134. A partially charged system will not accept a full charge without going to a full vacuum first.

Depending on the severity of your leak your A/C will blow cold for 1 day to 4 months but if you have a leak (you probably do if the R134 improved you're cooling capacity) then the Dye will make it easy for a technician or you to find the R134 leak later.

Like I said above it is hard to properly charge A/C without taking the system to full vacuum as the A/C machines in shops has a feature to do so.
I hope this helps.
PHX F250
ASE Master, Mercedes Benz Master Diagnostic Technician.

 

[PHXF250]

I'm having AC problems too. A few weeks ago mine started blowing warm air occasionally (with max air and coldest setting). Took it to local Firestone store, they said it was 2 pounds low on Freon (first time to add since new in 2002). Couple of days later, still blowing hot and cold air, took it back, and they said it could be the compressor or evaporator going out. Lately I've noticed that when the engine is running at 1500-2000 rpms, blows cold air most of time. However when engine is below 1500 rpms, and especially idling at stop lights, it blows hot, but when the engine gets back up to 1500+ RPMS, blows cold again. Any suggestions/ideas? I probably should take it to an AC shop.

Yeah take it to the dealer or an A/C shop. Evaporators dont go out, they either leak or they dont. The Evaporator is the radaitor looking thing closest to the center vents of the truck. It gets cold and the blower moter blows the then cooler air out the vents. Your probelm sounds more intermittent the the other guys does but once again I would have A/C injected after repairs to find and current of future leaks easier as A/C leaks are the No.1 reason any A/C is not cooling but i dont think that is the problem with your.

Thank goodnees my A/C is working well its 103f today in Phoenix.
PHX F250

 

[02SilverStroke]

JL, I haven't had a chance to "hose down" the condensor yet, but will soon. PHX 250, the Firestone shop did vacuum it and installed the dye and said there were no leaks. They originally said the freon was 2 pounds low. I didn't think that it even held that much. Another "quirk": I was behind a guy yesterday who was driving about 40 (when the speed limit was 50), and since it was below 1500 rpms the warm air started. I locked out the overdrive to increase the rpms, and cold air started blowing again. I'll try to run the water through the condensor tomorrow and let you know how it goes.

 

[PHXF250]

Yeah I just went outside and the label on the top radiator support on the right side of the truck on my 99 PSD calls for 2.8 lbs of R134. You are gonna need more in depth Diagnosis with some Gauges. If you had only .8 lbs of R134 and need 2.8lbs That would for sure cause you problems.

I was looking at my condensor (it's in front of your radiator and I dont have the Aux elect fans like some vehicle have. The air flow through it from driving speed the the belt driven fan are all you have to lower high side pressures. I would try and hose this condensor down and see if the A/C blows cold. If not I would suspect a problem with the Expansion valve causing a restriction of refrigerent flow or the compressor. I wish I could throw my gauges on your truck. Use Mine to indecate baseline pressures under operation and then mesure yours, at both lower and the higher RPM when it's working.

Also look at you condensor, is it super caked with bugs? If so take off the grille and use a plastic brush and scrub up and down and remove all of that crud. You should do this to insure cool eng running anyway. I took 3 pictures, One of the label, The low side A/C connection and the High Side Connection. Hope this helps. The Grill comes off easy, screws along the top and some clips on the lower side.
PHX F250

P.S. Yes I realize my Phone Camera Couldent get a clear enough Picture to read the label but shows you where it is and what it looks like. The A/C charge spec in on the lower left side of the lable below that black smudge mark.

 

[02SilverStroke]

hose down the condensor (a/c radiator on front of truck) and see if it improves..

got a couple scenarios this might be, so I need a tad more information..

while you're hosing off the condensor, time the compressor cycle as well

JL, I hosed down the condensor and it seemed to improve a bit. However, I couldn't hear the compressor shutting on and off, so I couldn't time it.