The A/C in my 2002 Ranger, 3.0L, is working for short periods either cooling fine or not blowing air out the vents. I would assume the evaporator is freezing up and the system needs freon. I put my gauge set on the system and read 100 psi on both the low and high pressure sides and, hence, cannot add freon. So what does this mean? I've been told the compressor is worn out but it will cool at times. Any thoughts on this?
Have you cleaned the living death out of the condenser? I have found many vehicles which needed it badly and AC worked afterward. Well worth a shot.
Did you get that 100/100 reading with the compressor running (clutch actually engaged)? A/C (and heat) can do funny things with an underhood vacuum leak. If the air (vents) work under high vacuum but not under advanced throttle you may have a bad hose between the vacuum reservoir and the vent vacuum actuator. If the orifice is plugged you should see a difference in high side and low side pressure when you firs turn the air on until the high limit turns the compressor off.
This is strange. The A/C works nicely about half the time. No air blowing the other half. No difference under high or low vacuum conditions. I really need to check this all out again when I have a bit more time to be sure the compressor was running. I'm wondering what the A/C pressures should be with the compressor in an off state.
Equalized, it would be the same pressure on both high and low which probably why the same reading, as plumcolr stated, verify clutch is engaged and compressor is turning. If not I would guess low freon or bad low pressure cut off switch.
Pressure depends on air temperature. This chart gives pressures for low and high sides during operation.
I rechecked the pressures and match the chart. NOW I find there must be an in-cab air flow problem - quite sensitive to vacuum conditions. I started the truck this morning and very little air flow out of the vents. Then suddenly full cold air flow. I don't see a vacuum reservoir under the hood like my Ranchero so have yet to understand this one.
It isn't the same...no soup can for you! It's a spherical black plastic tank with two nipples and two feet for mounting, and I believe it's on the driver fender well, next to the fuse box. I've screenshot some pages you'll need for basic diagnosis, but I have to reduce their size first before posting them, which I'll do in a PM.
NM, I forgot that files can't be uploaded in Conversations. Anyway, I left some operation info up there, and here are the photos: Hopefully, you'll get this problem diagnosed. I've been dealing with my friend's Comanche pickup that we retrofitted A/C into, and it's doing the same thing, the vacuum isn't working correctly.
I checked. No vacuum reservoir under the hood for this 2002 Ranger. I was hoping they quit using vacuum motors by 2002. I do have the shop manuals which clearly I need to read.
If it has vacuum operated air doors, it likely does have a vacume reservoir hidden somewhere. It could be done similar to Fox Body Mustangs or Thunderbirds, the reservoir could be hidden under the front fenders with the fender inner liner obscuring your view of it. Or possibly it could be using a reservoir like on my TownCars. They have the reservoir built into an electrical relay holding box, clever design that hides the vacuum hose under the relay wiring. What I'm saying is the reservoir may be hiding in plain sight, not a conventional old school shape you would know by sight. I would start checking at all the connections to the intake manifold then follow all the lines.
Ford also used plastic hard lines for vacuum and they will crack or break leaving a leak. Harder to trace too. If you have that tubing and find a bad spot, cut it out and replace the section with good ol' rubber vac tubing. Now would be a good time to have a hand powered vacuum pump.
You'll need to follow the vacuum from the intake manifold. Some fords have a fitting on the power brake booster which has nultiple ports. Most 2000 and newer fords that I have seen have a vacuum canister tucked in the passenger fender by the firewall. Just look at all the (ugh! plastic) lines you can see along the firewall. Be prepared to replace ALL of them with good ol' rubber lines.
Another possibility if this ranger has IWE type 4wd is a bad line to the wheels. I kinda doubt it has IWE tho.
Ok, studied this some more. Under poor vacuum conditions, the air flow defaults to the defroster vents - exactly what I have and failed to notice. I also found the vacuum reservoir hidden under the intake air filter box. Now to check for vacuum leaks!
Time to build a smoke machine.If your brake bleeder has a gauge it will work,but takes longer.Dont forget to check heater control valve.