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93 Explorer Vent Temp High

Minx on Sun April 20, 2008 8:29 AM User is offlineView users profile

Year: 1993
Make: Ford
Model: Explorer
Engine Size: V6
Refrigerant Type: R134
Ambient Temp: 82
Pressure Low: 34
Pressure High: 250
Country of Origin: Vatican City State

The center vent temp won't go below 59 degrees ... and this is not a hot day by Dallas standards.

At 1,500 RPM the clutch starts cycling between 28 and 51 on the low side, 155 and 210 high side.

At idle the clutch won't cycle and the low stays at 34, high at 250.

Either way, vent temp is stable at 59.


I added a valve to the heater hoses that diverts the flow when AC is at maximum. I operated it manually while testing and it did not affect vent temps.

The system was converted to 134 at a shop, while with the previous owner. The compressor looks original. Condenser is the more efficient OEM type for this year. I don't know which o-tube is in there.

All readings taken at center vent, max AC, in the shade, after 10-minute run-in.

Any ideas, guys?

brickmason on Sun April 20, 2008 1:25 PM User is offline

The cycling switch needs to be adjusted to cut out -cycle- at 19 to 21 psi.

If equiped, there will be a screw in between the 2 prongs after unplugging the cycling switch.

Just turn the screw counterclockwise about 1 and a half rounds to lower the cut out pressure.
If the pressure is too low then simply turn it a quarter round or so clockwise to increase the pressure.

The fan clutch is probably weak also.

Making sure the condenser is clean and free of bugs and debris will help tremendously with the vent temp at idle.

One other thing. make sure the recirculate door is opening all the way. The actuator is located on the left side of the firewall underneath the hood. Works off of vacuum and is very common to fail on those year models. Simply switching the A/C control knob from max to recirculate is what moves the actuator arm to open, close the recirculate door. Make sure it moves all the way in either direction.
If in MAX position you can manually push the controll arm to see if it is closing all the way to keep the outside air from entering the ductwork.

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Just another brick in the wall

Had a little mule I fed him castor oil and every time he jumped the fence he fertilized the soil

Edited: Sun April 20, 2008 at 1:38 PM by brickmason

chris142 on Sun April 20, 2008 7:14 PM User is offline

I replace a lot of heater control valves on those. If the AC is on and the heater hoses are hot you need a new valve.

Chick on Sun April 20, 2008 7:32 PM User is offlineView users profile

Feel the return like (suction) to the compressor, is it cold? inlet and outlet about the same, outlet slightly cooler? The system won't drop to cycling pressures, and the switch doesn't make it, so until you figure out what is wrong, leave the switch be for now.. Also feel the lines, which are warm, which are cold..You could be on the verge of a compressor failure, bad fan clutch or both....You need to find which. You can hook up your gauges, spray a "mist" of water on the condenser, if the high side drops like a stone, you have airflow problems, and possible low charge. If they drop slowly, you can rule air flow out for now..Let us know what you find...

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

brickmason on Sun April 20, 2008 8:14 PM User is offline

Quote
Originally posted by: Minx
The center vent temp won't go below 59 degrees ... and this is not a hot day by Dallas standards.



At 1,500 RPM the clutch starts cycling between 28 and 51 on the low side, 155 and 210 high side.




















Chick,

The low side is cycling too high to provide adequate cooling. 8 psi lower will make a big difference in lowering the vent temp. The shop which converted it probably did not touch the switch.



But hey, what little I do know, I learned from you!!! Right?

























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Just another brick in the wall

Had a little mule I fed him castor oil and every time he jumped the fence he fertilized the soil

Chick on Sun April 20, 2008 8:50 PM User is offlineView users profile

That is true, but I think (think) it's an airflow problem with "low charge". It shouldn't drop down to 155psi high side at 80 degrees (fan is working better at high rpms ) If he were to jump the cycling switch, bet it would keep dropping (both low and high) ..Just a thought though.. An air flow problem needs to be fixed first, and the water test is fast and easy to check . looks like a bad fan clutch and recharge to me....But I have been wrong before...I believe the 93 used the FX15, which should not be run with a low charge, black death imminent...

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

Minx on Sun April 20, 2008 9:00 PM User is offlineView users profile

I haven't mentioned that I replaced the fan clutch two years ago with a Motorcraft, trying to solve a hot-idling problem. However, I still have that problem (though it diminished with a new thermostat), so it's possible the new clutch isn't even as good as the one I replaced.

I'll try the water-spray test and let y'all know what I find. Thank you for the suggestion.


I guess the O-tube is unlikely, as no one's mentioned it? I don't know whether the shop replaced it when they converted the vehicle to R-134a.

Chick on Sun April 20, 2008 9:33 PM User is offlineView users profile

if it comes down to a bad airflow and low charge, you should check the O tube before recharging as it will tell you if the compressor suffered from bad oil circulation..You want to find it now, if it's failing, it is only going to get worse with those compressors (Repair wise)

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

Minx on Sun April 20, 2008 9:38 PM User is offlineView users profile

Thank you, Chick. Any suggestion on size for the O-tube? Seems I remember some advice to change when converting to 134, but I'm not sure it applies in this case.

Chick on Sun April 20, 2008 10:00 PM User is offlineView users profile

I believe the stock O tube is blue and that is fine..I'm more concerned on what it looks like... One step at a time...

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

brickmason on Sun April 20, 2008 10:05 PM User is offline

Quote
Originally posted by: Chick
That is true, but I think (think) it's an airflow problem with "low charge". It shouldn't drop down to 155psi high side at 80 degrees (fan is working better at high rpms ) If he were to jump the cycling switch, bet it would keep dropping (both low and high) ..Just a thought though.. An air flow problem needs to be fixed first, and the water test is fast and easy to check . looks like a bad fan clutch and recharge to me....But I have been wrong before...I believe the 93 used the FX15, which should not be run with a low charge, black death imminent...






See Chick,


You know more about MVAC than anyone. You should change your username to Ultimate Mr. Cool.

Bet I can lay more brick than you!

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Just another brick in the wall

Had a little mule I fed him castor oil and every time he jumped the fence he fertilized the soil

Chick on Sun April 20, 2008 10:08 PM User is offlineView users profile

Hah, I can't lay them at all!!! to dam heavy...

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Chick
Email: Chick

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Freedoms just another word for nothing left to lose

brickmason on Sun April 20, 2008 10:24 PM User is offline

Quote
Originally posted by: Chick
Hah, I can't lay them at all!!! to dam heavy...




Hey, after 23 years of it, they dont get any lighter at the end of the day, just heavier.

Even on a Monday.

Crap, thats tomorrow, now my backs hurting again !!!

I used to be 6 foot tall when I started bricklaying...... Now thats lying down.... Not much over 4 feet now standing up. Ouch!!!

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Just another brick in the wall

Had a little mule I fed him castor oil and every time he jumped the fence he fertilized the soil

Minx on Sun May 11, 2008 3:34 PM User is offlineView users profile

Many thanks for all y'all's thoughts on this Explorer. Here's the progress so far:

I misted the condenser and the high side plunged from 250 to 180.

I added half a can of R-134a, which brought the vent temp down from 59 to 49. Cycling continued at idle as long as I kept misting the condenser.

Then I took a drive. The vent temp fell to 42-52 (cycling), leveled off at 44 (coasting), then rose to 48 at full stop. I figure the cycling stopped because the temperature stabilized.

So with more refrigerant I'm running cooler but still not cycling at idle. I know these cars had airflow problems, which is why I cleaned the condenser and behind the transmission oil cooler last summer, and installed a new fan clutch and 10-blade fan.

Do you think I should try a bit more R-134a, or some other course?

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