AC Issue

[MarkCCU]

I read a few other AC threads but didn't see one (or I missed it) that was close to what I am experiencing.

My AC blows hot when idle. It seems that at faster speeds it'll blow cold. The condenser and the clutch are fine. Is it the blend door? Perhaps a recharge of the system?

I have the 03 Sport XLT, if it matters. Thanks everyone.

 

[MarkCCU]

I don't hear any noise, btw.

 

[J_C]

Don't know the setup on a '03 Sport (which engine? 4L SOHC?) but one suspect is the radiator fan motor whether it be electric or the clutch to it. If it's a clutch type I assume the belt for it is still there. You wrote the clutch is fine but does that mean only that you observe it working from time to time, or that it's also working during the idle period when A/C blows warm?


Two more are low refrigerant or worn out compressor. I doubt it would be the blend door as even if it's vac operated and you had a vac leak, it should be higher at idle not lower, making a vac leak less significant since it seems to operate correctly to get cold air when not at idle.

 

[MarkCCU]

Don't know the setup on a '03 Sport (which engine? 4L SOHC?) but one suspect is the radiator fan motor whether it be electric or the clutch to it. If it's a clutch type I assume the belt for it is still there. You wrote the clutch is fine but does that mean only that you observe it working from time to time, or that it's also working during the idle period when A/C blows warm?


Two more are low refrigerant or worn out compressor. I doubt it would be the blend door as even if it's vac operated and you had a vac leak, it should be higher at idle not lower, making a vac leak less significant.

I observe it working, I can hear it making that clicking noise when it pops in or out (my mechanic buddy that looked over the car before I bought it said it was good). It has coolant, though I'll double check to make sure. I just put some in a few weeks ago. Is there any visual way to check the compressor?

 

[J_C]

No visual way I'm aware of, besides confirming that the clutch on it is kicking in as it should be. I suppose it could be an early sign of a high or low side AC pressure sensor failing but I'd think it would exhibit the problem at higher than idle RPM too.

To be clear, I don't know which clutch you were originally talking about but previously I was talking about the fan clutch and now the compressor clutch.

 

[koda2000]

Best way to test the refrigerant level is to have the dual gauge set. It sounds like you may be low on refrigerant. If you don't have a set of A/C guages it might be best to take it to an A/C shop and have them test it. Just adding refrigerant without knowing if you need it can be risky (blown hoses) and even if you don't hurt anything, you can make the system's performance worse, because the pressure switches will stop the compressor from working efficiently if the pressure is to HI or to LO.

How long is it between the compressore clicking on and off?

 

[MarkCCU]

Best way to test the refrigerant level is to have the dual gauge set. It sounds like you may be low on refrigerant. If you don't have a set of A/C guages it might be best to take it to an A/C shop and have them test it. Just adding refrigerant without knowing if you need it can be risky (blown hoses) and even if you don't hurt anything, you can make the system's performance worse, because the pressure switches will stop the compressor from working efficiently if the pressure is to HI or to LO.

How long is it between the compressore clicking on and off?

I hear the clicking pretty often. Every few minutes or so...

 

[koda2000]

I hear the clicking pretty often. Every few minutes or so...

As I recall, mine cycle every 10-15 seconds or so.

 

[MarkCCU]

As I recall, mine cycle every 10-15 seconds or so.

You're right. I timed it. It's about every 10 seconds.

 

[SoHK_alumni]

The "blows hot at idle" and the clicking clutch every 10 seconds or so are likely related.

If the fan clutch is not engaging and having the fan pull air across the condenser/radiator, the high pressures in the a/c system will cause the high side pressure switch to trip causing the poor performance and cycling of the clutch.

At speed, or at least when moving, the fan is not as critical in getting air across the condenser so the high side switch stays satisfied and the a/c system can do it's job.

Easy way to verify is to install a jumper on the LOW pressure switch plug. If the symptom continues, it's the high switch causing the cycling and definitely NOT time to add any more refrigerant.

Jumping the high pressure switch should be avoided, if the high switch is doing it's job, your a/c pressure will go absolutely nuts if the switch is jumpered out and could cause significant damage.

Yes, a proper dual pressure gauge set is best for checking a/c pressures and if the fan clutch is proven to be good, then you'll need a set of gauges to verify the pressures at which the switch is cycling the compressor.

 

[chefduane]

I bet low on refrigerant and/or leak or bad seal somewhere. You could just do a refrigerant recharge and see what you get, or get some of this

http://www.autozone.com/test-scan-a...iversal-a-c-uv-dye/210226/?_requestid=2337625 and a UV light to look for leaks.

Or this http://www.ebay.com/itm/Halogen-Lea...ak-Detector-R134a-R12-R22-R410a-/351534678389.

Dual gage set is your best bet http://www.ebay.com/itm/like/361105064081?lpid=82&chn=ps&ul_noapp=true.

Or take it to a $hop and have it looked at.:thumbdwn:

 

[MarkCCU]

I bet low on refrigerant and/or leak or bad seal somewhere. You could just do a refrigerant recharge and see what you get, or get some of this

http://www.autozone.com/test-scan-a...iversal-a-c-uv-dye/210226/?_requestid=2337625 and a UV light to look for leaks.

Or this http://www.ebay.com/itm/Halogen-Lea...ak-Detector-R134a-R12-R22-R410a-/351534678389.

Dual gage set is your best bet http://www.ebay.com/itm/like/361105064081?lpid=82&chn=ps&ul_noapp=true.

Or take it to a $hop and have it looked at.:thumbdwn:

Thanks! I am probably going to recharge it for a 2.5 hour trip I have with my wife and kid and when I get home I'll do the diagnostic.

It's certainly getting cold (the ac) and sometimes there's no trouble like this morning or yesterday afternoon. But it's getting hot in South Carolina and a working HVAC is something nobody wants to go without.

 

[koda2000]

The "blows hot at idle" and the clicking clutch every 10 seconds or so are likely related.

If the fan clutch is not engaging and having the fan pull air across the condenser/radiator, the high pressures in the a/c system will cause the high side pressure switch to trip causing the poor performance and cycling of the clutch.

At speed, or at least when moving, the fan is not as critical in getting air across the condenser so the high side switch stays satisfied and the a/c system can do it's job.

Easy way to verify is to install a jumper on the LOW pressure switch plug. If the symptom continues, it's the high switch causing the cycling and definitely NOT time to add any more refrigerant.

Jumping the high pressure switch should be avoided, if the high switch is doing it's job, your a/c pressure will go absolutely nuts if the switch is jumpered out and could cause significant damage.

Yes, a proper dual pressure gauge set is best for checking a/c pressures and if the fan clutch is proven to be good, then you'll need a set of gauges to verify the pressures at which the switch is cycling the compressor.

I'm the one that said my compressors click every 10 seconds or so. All of my Explorers and Mountaimeers do this and they all blow cold air all the time, no issues at all. The OP said his compessor clicks every few minutes. I imagine the abietment temp and maybe humidity have something to do with the cycle time, but every few minute seems like a long time to me.

 

[MarkCCU]

The "blows hot at idle" and the clicking clutch every 10 seconds or so are likely related.

If the fan clutch is not engaging and having the fan pull air across the condenser/radiator, the high pressures in the a/c system will cause the high side pressure switch to trip causing the poor performance and cycling of the clutch.

At speed, or at least when moving, the fan is not as critical in getting air across the condenser so the high side switch stays satisfied and the a/c system can do it's job.

Easy way to verify is to install a jumper on the LOW pressure switch plug. If the symptom continues, it's the high switch causing the cycling and definitely NOT time to add any more refrigerant.

Jumping the high pressure switch should be avoided, if the high switch is doing it's job, your a/c pressure will go absolutely nuts if the switch is jumpered out and could cause significant damage.

Yes, a proper dual pressure gauge set is best for checking a/c pressures and if the fan clutch is proven to be good, then you'll need a set of gauges to verify the pressures at which the switch is cycling the compressor.

So the clutch is engaging. I'll check the pressures. What do I do if the high pressure/low pressure isn't where it should be?

 

[MarkCCU]

I'm the one that said my compressors click every 10 seconds or so. All of my Explorers and Mountaimeers do this and they all blow cold air all the time, no issues at all. The OP said his compessor clicks every few minutes. I imagine the abietment temp and maybe humidity have something to do with the cycle time, but every few minute seems like a long time to me.

I went back and actually listened to my car and watched the clutch engagine. It's every 10 seconds or so. I was mistaken.

 

[MarkCCU]

How do you guys feel about Stop Leak products

http://www.autozone.com/a-c-chargin...-driven-compressors/441054_0_0/?checkfit=true

 

[koda2000]

How do you guys feel about Stop Leak products

http://www.autozone.com/a-c-chargin...-driven-compressors/441054_0_0/?checkfit=true

The last time I tried a A/C Stop Leak (guarantied to stop the leak) it worked so well that it completely clogged my accumulator/drier. I ended up having to replace the accumulator, and while I was at it, I flushed the system and replaced all the A/C O-rings. After recharging and adding refrigerant oil the system it worked fine.

I think the regular refrigerant with stop leak would be safe to use, but who knows if it will work. You might be better off using a florescent dye first to determine if/where the leak is. If it's the compressor seal stop leak probably wont help.

If the vehicle is moving (say at 55 MPH) and you put it in neutral and coast does it blow warm/hot air at idle? If not the problem may be your fan clutch.

 

[J_C]

I doubt it would have enough time to heat up without the fan spinning on a coast from 55 MPH considering the vehicle is a brick on wheels and the front grill is open enough to get a fair amount of passive airflow through it.

 

[koda2000]

I doubt it would have enough time to heat up without the fan spinning on a coast from 55 MPH considering the vehicle is a brick on wheels and the front grill is open enough to get a fair amount of passive airflow through it.

That's the point. If it keeps blowing cold while coasting, with air being pushed through the condenser, by the movement of the vehicle, but gets warm with the vehicle standing still at idle, then the fan isn't doing it's job. Maybe 75 MPH is a better speed.

 

[MarkCCU]

A few things I've noticed:
had cold air at idle
Cap for low side port missing
Leaking coolant. I filled the tank two weeks ago and now it's damn near empty