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No Leak, 40psi low side, cmprsr works sometimes

Frustrated in KC on Sat August 25, 2007 7:17 PM User is offline

Year: 1995
Make: Ford
Model: Windstar
Engine Size: 3.8L
Refrigerant Type: 134a
Ambient Temp: ?
Pressure Low: 40+ psi
Pressure High: ?
Country of Origin: United States

Help please Help!! Here's my problem: I get cooling only when freon is added. I know you're thinking hello McFly you have a leak. Well, that's just it. I've used UV dye but have not found a leak. In addition, the system maintains 40+psi and when I add freon it increases. Compressor clutch turns, controls work, fan is ok. So here's what happens: I'll add about 1 lb of freon, then wonderful 40 degree discharge air in the cabin, 2 days later it's blowing hot air. By this time, the compressor kicks on for about 2 seconds and then stops. This process can be repeated.

95 Ford Windstar, 3.8L, 125k, rear a/c

What in the heck is going on??

Signed,

Frustrated in KC

bohica2xo on Sat August 25, 2007 7:41 PM User is offline

Mcfly, you have a leak.

Check your evaporator drain tube for a pretty green glow...


B.

Edited to correct outrageous spelling error... LOL

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

Edited: Sun August 26, 2007 at 2:31 AM by bohica2xo

newton5 on Sun August 26, 2007 2:20 AM User is offlineView users profile

Would that be Evaporator drain tube there Bohica?

Edited: Sun August 26, 2007 at 2:21 AM by newton5

NickD on Sun August 26, 2007 8:14 AM User is offline

LOL, very well possible that McFly is not having a leak, with all these Chinese virus's going around, could be some kind of Asian bug in his system that is eating the refrigerant.

But if the system cools well by adding a pound of R-134a every couple of days, what else can it be, but a leak? And a major leak at that, McFly should try to find out why a system is losing 2 ounces per year, not a pound every two days. McFly needs a good manifold gauge set and should check with Tim for a decent electronic leak detector.

There are different kinds of leaks, some just leak out oil and dyes with very little refrigerant loss, very typical of springlock systems, upper seal leaks where only refrigerant is loss, and hard leaks where both refrigerant and oil/dyes are lost. These with just oil leaks are the worse kind as you are only replacing the refrigerant, but not the lost oil. Sound logical, Mr. Spock?

I won't even venture to speculate where his leak is at, but should be somewhere in the AC system, so don't bother checking the AT or the PS.

Frustrated in KC on Mon August 27, 2007 9:50 AM User is offline

Thanks for the responses. I was convinced it was a leak at first too. I know this sounds and look like a leak, however, why would I read 40+ psi on low side. I have pumped the system down before and replaced with new R-134a only to have cooling again for a couple days. I have even inadvertently charged the system up to 75lbs psi and it held the pressure. I have not been able to find leaking dye anywhere.

Could there be a leak and still read 40+psi on low side?

bohica2xo on Mon August 27, 2007 12:23 PM User is offline

The low side pressures are meaningless without high side pressures as well.

You need to get a decent service manifold (gauge set) and record BOTH the high side & low side pressures - while running the engine @ 1500 to 2000 rpm, doors open, cabin fan on highest speed.

Refrigerant is added by weight, NOT simply the low side pressure. Topping up a leaker like yours is just a slow march toward an even more expensive repair.

B.

-------------------------
"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.

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