Mariner A/C

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Jun 17, 2011 | 04:52 PM

twg1966

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Trying to Gain Knowledge

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From: Ezzell, TX

Mariner A/C

Question for everyone: Under heavy acceleration or at highway speeds, the a/c doesn't blow cold air. When you drop off the accelerator the cold air returns. What could be causing this issue?

Ted

Jun 17, 2011 | 09:03 PM

projectSHO89

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From: St Louis

Depending on the year, it's probably normal (under the control of the PCM to free up horsepower for acceleration). Check your owner's manual.

Jun 17, 2011 | 09:23 PM

wptski

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From: Warren, MI

Normal under WOT.

Jun 18, 2011 | 11:14 AM

twg1966

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Trying to Gain Knowledge

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From: Ezzell, TX

Sorry, I forgot to post the year. It is a 2005 and we had this problem shortly after purchasing, then it seemed to disappear and now it is back. I will continue to monitor it and see if it continues.

Jun 18, 2011 | 06:12 PM

projectSHO89

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From: St Louis

While you're at it, check the clutch air gap. An excessive gap can allow the clutch to slip under high-load conditions. If the gap is over .035", perform a shimectomy.

Jun 19, 2011 | 12:16 AM

Torky2

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Quote:

Originally Posted by twg1966

..... When you drop off the accelerator the cold air returns. What could be causing this issue?

Are you sure the cold air is really going away, or is it being redirected to the defroster vents? Get on the highway and duplicate it, and when it appears to go away, put your fingers up into the defroster vents.

Our trusty Grand Caravan, the predecessor to our Escape, developed that over the years. Going up a hill on the interstate, after a little bit the airflow would shift to the defroster vents (the safety default). I looked all over for vacuum leaks, which are usually the problem on Ford vehicles with vacuum-controlled air direction, but found none. The one-way check valve to keep vacuum in the vac reservoir in high engine load conditions (wider opening of throttle - low intake vacuum) seemed to work ok each time I tested it. Finally pulled out the check valve once, and had it pass air both ways for an instant, then okay. I replaced the check valve, that fixed the problem.

I'm assuming your year's would have vacuum controls, but I don't know for sure.