A/C turns hot on acceleration

[TheJMan]

This problem has me stumped. When I accelerate up an on-ramp, to pass, or any situation where a good amount of throttle input is needed, the air coming out of the vents becomes very hot. When the engine is at cruising speed, the air cools down again. In other cars I've driven, when I accelerate, the air cools down and only heats up when idling or moving slowly. Could it just be a low refrigerant problem? I'm pretty sure I have the infamous 5.0 exhaust manifold leak, as it ticks from 3k on up. I just hope the exhaust gas isn't leaking onto the A/C components.

 

[Skibug]

I have a simular problem. Mine does not get completely hot, but does warm up somewhat. I am also interested in what others here have to say about this. I have checked my refrigerant, and it is not low.

 

[JDraper]

IF I remember correctly, that's how the vehicles are designed. The compressor turns off under heavy acceleration to keep more power going to the wheels. No compressor running, no cold air....

Depending upon who you listen to, the compressor robs between 5 and 20 hp from the drivetrain.

 

[Robb]

There is a WOT (wide open throttle) relay under the hood that disconnects the compressor clutch when you get near WOT. It allows the vehicle to have more acceleration when needed.

edit: my typing is getting slower and slower

 

[crimbeaux]

IF I remember correctly, that's how the vehicles are designed. The compressor turns off under heavy acceleration to keep more power going to the wheels. No compressor running, no cold air....

Correct. I had a Crown Vic with the 4.6 and asked the dealer about this. They confirmed this.

 

[TheJMan]

Well, maybe I'll just have to keep my foot out of it from now on, cause it's been around 115 here lately, and sometimes that air gets mighty hot from those vents.

 

[LilCop2002]

I know that I'm a little late, but if your engine coolant temps start to rise as well, check to see if your Tstat is going bad. I ahd that same problem as you described, but my TStat went south

 

[ezrider440]

check your fan clutch first of and second make sure your pressures are to spec, also check your orfice tube , the WOT relay will turn the a/c off if your force the truck to downshit hard or do a burn out.

 

[gijoecam]

You can check all you like, but as was mentioned above, there's a WOT cutout for the AC compressor. If you don't quite floor it, it may help keep the truck cool, but obviously acceleration will suffer. Additionally, I suppose you could pull the WOT cutout relay, but I wouldn't suggest that myself.... I'd rather sweat a bit than have trouble passing that semi!

-Joe

 

[Glacier991]

I read the symptoms and my first thought was exactly what people have hinted at, bad WOT relay cutout.

 

[VOATMJ1]

Yep, the compressor will cut out when the throttle is depress to a certain extent closing in on WOT. My Explorer does this, the '86 Bronco II that I had did this, my Caddy does it, and even waaay back in the day when I had my 1975 Mercury, it did it. This is not new technology. This has been around for a while on all vehicles. Your truck is working properly, and being that it is 115 out, (I can relate...it's been triple digit temps here as well) you will get if you are using the "normal" A/C setting, warm air until the compressor kicks back in after the throttle is back to normal, after all, were talking temps over 100! In the "Max" setting, is should not be too hot or even a little warm, as you are recycling the inside cabin air and not the reverse with the normal setting.

 

[ford96gtconv]

My a/c will just get hot than floor it, it gets cold again?

I have a 1998 Explorer XLT 4.0 I will be driving along and the Air just gets hot. If I floor it and down shift the engine it gets cold again. Can stay cold for a miles than will get hot again?? Please help way toooo HOOOTTTTT..

Just bought this car 2weeks ago...


Jim
Brandon, Fl

 

[Macgiobuin]

You may have a bad heater control valve. When you up the rpm's of your engine, the head pressure of the coolant going through your heater hoses, that is supposed to be cut off by the heater control valve, causes the coolant to flow through your heater core, which modifies the temperature of the air flowing through, so that it is cooled then heated. I had this occur in a neighbor's European luxury car, where I diagnosed it, and his fix was to just plug the heater hose during the summer. That's a good way to diagnose temporarily, not my idea of a permanent fix. If you need to replace the valve, do that.

 

[ford96gtconv]

The compressor does keep cycling on and off at idle?? It seems like it act's up after engine is warmed up alot?