Solved A/C LOSS CLIMBING HILLS

[imp]

2004 XLT 4.0 SOHC, 185K. A/C works fine, all settings, but lately cuts out when more power is demanded, like climbing a highway incline. When this occurs, blower motor is heard to continue running, but little or no air is discharged from dash vents. Upon backing off throttle demand, normal A/C returns.

In my mind, this is happening as vacuum reservoir is depleted, due to a vacuum leak. There is a reservoir permanently attached to the engine air inlet duct, before the throttle body. I cannot conclude in my mind whether a leak BEYOND the throttle body (hoses, connections, power brake booster) or BEFORE the TB in the duct containing the Mass Air Sensor would be responsible.

Otherwise, truck runs very well. Idles normal and smooth. Starts as it always has. I am open to thoughts!!

Edit: solved post 11
Thnx mgmnt

 

[94Eddie]

You probably need an air conditioner control valve. It is a one way valve that allows the vacuum reservoir to hold a vacuum when the engine is under load and not producing a vacuum. It is a two minute job to replace and is an inexpensive part. The valve is located near the upper firewall on the passenger side and is easy to spot. Just make sure to orient it properly since it is directional. You can buy one at the link below.

Amazon product ASIN B000NU8FFY

 

[Rcflyer330]

That does sound like a bad ac check valve. does the airflow go to the defrost position when it happens? this would definately indicate a bad ac check valve.

 

[Bazz270]

Check for firewall vacuum hoses grommet leaks.
Replace the whole vacuum line thru the firewall

 

[imp]

You probably need an air conditioner control valve. It is a one way valve that allows the vacuum reservoir to hold a vacuum when the engine is under load and not producing a vacuum. It is a two minute job to replace and is an inexpensive part. The valve is located near the upper firewall on the passenger side and is easy to spot. Just make sure to orient it properly since it is directional. You can buy one at the link below.

Amazon product ASIN B000NU8FFY

I suspected the check valve but have been unable to find the damned thing. It is pictured in the shop manual.

 

[Rcflyer330]

08 Explorer Eddie Bauer A/C Problem

Hi there. I'm having an issue with my A/C. While running A/C through the console vents everything seems fine until you accelerate. Then it starts blowing through the defrosters. Sometimes shortly after you stop it starts blowing through the console vents again. Then after accelerating again...

www.explorerforum.com

check out post #4 its shows the location in red and should be similer location for both v8 or v6

 

[94Eddie]

I suspected the check valve but have been unable to find the damned thing. It is pictured in the shop manual.

Its location should be something like it is shown below in the red circle.

 

[azpima67]

happened to me in a 2010 EB with V8. Was a vacuum hose leak. Here's what I posted about it a year ago:
On recent trip up north the fan stopped working (outside air & AC) when loading the engine such as going uphill. Typical vacuum problem, in my experience. At my son's town (Brigham City, UT) I had the local Ford dealer (but one of the multi brand mega dealers) fix it. They replaced a vacuum line due to a small crack. That fixed it but they took it for a test drive and said "concern was still present".. Recommended that the "climate control solenoid and manifold assembly is leaking" per a smoke test. Part not in stock and wait was 3 days (and some $400 cost). Declined since I could live with the problem ( AC/outside air blower works when no load on engine) and my schedule didn't permit the delay (had 2 HS grand kids graduations to attend).

The next day went to WY over steep mountain grades without any problems -- blower never cut out. Same on the rest of the rip up to S. Idaho and back to Tucson and around Tucson in 100+ degree temps..

While working on the Exp they checked the brakes, tires and battery which were all OK. So I am wondering if the recommended solenoid/manifold really needs replacing?

Still working fine in 2022

 

[94Eddie]

happened to me in a 2010 EB with V8. Was a vacuum hose leak. Here's what I posted about it a year ago:
On recent trip up north the fan stopped working (outside air & AC) when loading the engine such as going uphill. Typical vacuum problem, in my experience. At my son's town (Brigham City, UT) I had the local Ford dealer (but one of the multi brand mega dealers) fix it. They replaced a vacuum line due to a small crack. That fixed it but they took it for a test drive and said "concern was still present".. Recommended that the "climate control solenoid and manifold assembly is leaking" per a smoke test. Part not in stock and wait was 3 days (and some $400 cost). Declined since I could live with the problem ( AC/outside air blower works when no load on engine) and my schedule didn't permit the delay (had 2 HS grand kids graduations to attend).

The next day went to WY over steep mountain grades without any problems -- blower never cut out. Same on the rest of the rip up to S. Idaho and back to Tucson and around Tucson in 100+ degree temps..

While working on the Exp they checked the brakes, tires and battery which were all OK. So I am wondering if the recommended solenoid/manifold really needs replacing?

Still working fine in 2022

You wouldn't be the potential first victim of dealerships scamming people into unnecessary repairs. They tried it nearly every time my wife dropped off her car at one for warranty repairs when I wasn't present. Heck, your problem might have been the $10 AC control valve and they just ran up the tab. Did you actually lay eyes on the cracked vacuum line they replaced?

 

[azpima67]

Didn't see it but since no problem since, I figured they were correct. The dealer used to be a local family who sold to large multibrand group which seems to be the "way of the future"!

 

[imp]

happened to me in a 2010 EB with V8. Was a vacuum hose leak. Here's what I posted about it a year ago:
On recent trip up north the fan stopped working (outside air & AC) when loading the engine such as going uphill. Typical vacuum problem, in my experience. At my son's town (Brigham City, UT) I had the local Ford dealer (but one of the multi brand mega dealers) fix it. They replaced a vacuum line due to a small crack. That fixed it but they took it for a test drive and said "concern was still present".. Recommended that the "climate control solenoid and manifold assembly is leaking" per a smoke test. Part not in stock and wait was 3 days (and some $400 cost). Declined since I could live with the problem ( AC/outside air blower works when no load on engine) and my schedule didn't permit the delay (had 2 HS grand kids graduations to attend).

The next day went to WY over steep mountain grades without any problems -- blower never cut out. Same on the rest of the rip up to S. Idaho and back to Tucson and around Tucson in 100+ degree temps..

While working on the Exp they checked the brakes, tires and battery which were all OK. So I am wondering if the recommended solenoid/manifold really needs replacing?

Still working fine in 2022

Thank you for your answer. While you did not mention in, I wonder if operation is normal when set to "max a/c"? We reside along the Colorado River south of Bullhead City (AZ) where it is often hotter than Tucson. We run A/C set at MAX only.

After locating the vacuum check control, which is simply a one-way valve, I found the tube cracked close to the firewall. A piece of rubber hose fixed it.

 

[azpima67]

I use max all the time rather than regular which brings in and cools some outside air

 

[94Eddie]

I use max all the time rather than regular which brings in and cools some outside air

I think the "Max AC" setting on single zone systems changes to air recirculate mode which only recycles the cabin air and doesn't let outside air into the cabin at all. This way the AC system is not continuously cooling air at high outside temperatures. Instead it is cooling air that has already been cooled. This allows the cabin temperature to drop faster and to a lower level than always feeding hotter outside air into the system. Dual temperature systems have a dedicated recirculation button to do the same in any heating/cooling mode.

 

[Wrenchtt]

2004 XLT 4.0 SOHC, 185K. A/C works fine, all settings, but lately cuts out when more power is demanded, like climbing a highway incline. When this occurs, blower motor is heard to continue running, but little or no air is discharged from dash vents. Upon backing off throttle demand, normal A/C returns.

In my mind, this is happening as vacuum reservoir is depleted, due to a vacuum leak. There is a reservoir permanently attached to the engine air inlet duct, before the throttle body. I cannot conclude in my mind whether a leak BEYOND the throttle body (hoses, connections, power brake booster) or BEFORE the TB in the duct containing the Mass Air Sensor would be responsible.

Otherwise, truck runs very well. Idles normal and smooth. Starts as it always has. I am open to thoughts!!

 

[Wrenchtt]

You have a vacuum leak for sure.You have a dedicated vacuum line going to the firewall for the hvac system and the vacuum reservoir should have a one way check valve in line for this reason.When you are accelerating heavy up the hills your engine vacuum will drop off and that’s normal, The vacuum should hold your vent doors in place for you if not you have a bad check valve,vacuum leaking from one of your actuators inside your cabin, your reservoir itself, good luck with finding it. If you have a handheld vacuum pump that has a gage on it you can check your components one at a time or go directly to the main line entering your vehicle and it should hold vacuum. I hope this helps you with the issue.

 

[Turdle]

Solved, post number 11

 

[Wrenchtt]

Thank you for your answer. While you did not mention in, I wonder if operation is normal when set to "max a/c"? We reside along the Colorado River south of Bullhead City (AZ) where it is often hotter than Tucson. We run A/C set at MAX only.

After locating the vacuum check control, which is simply a one-way valve, I found the tube cracked close to the firewall. A piece of rubber hose fixed it.

Good job,it takes patience and time but you got it right!
Wrenchtt