AC vent temp won't go below 50 degrees

[buildingdoc]

It is true... most manufacturers do slightly undercharge... an oz per car can save a ton in the long run. But I don't think the problem is an undercharge issue. If so, you would have a lower suction pressure.

Your accumulator has two purposes. It boils off any remaining liquid refrigerant so that only vapor returns to the compressor. It should also contain a white or grey sack of desiccant that absorbs moisture because moisture and refrigerant create hydrofluoric acid that will eat up your seals from the inside out.

The condenser... it is a parallel flow condenser (old style was tube and fin). If your last condenser did have a catastrophic failure I would urge anyone to replace the condenser if you have a parallel flow. It is impossible to flush out. But at 90* and 230 on the high side... sounds like you are getting proper cooling at the condenser. Best way to confirm is get a temp in and out and you should see about a 20 degree drop. Also carefully take temps on the refrigerant lines between the condenser and the expansion valve to make sure the temp is consistent. If you notice a rapid drop in temp, that is a restriction.

This is a tough one. Have you checked to make sure the hot water valve is closing and not allowing any warm coolant to enter into the heater core? This is where experience really comes in and having hands on would tell the story much better.

 

[JUST4FUN]

http://www.expeditionforum.com/album.php?albumid=1&pictureid=3998
13 year old truck still running strong

 

[CVWheeler]

I know what the problem is. I need more Cow Bell !!

 

[CVWheeler]

I replaced the condensor yesterday, no change. Vent temp is still at 50 degrees. I've now replaced every component under the hood with no change. I did notice a slight drop in pressure on the high side after I replaced the condensor so the old one was definitely clogged. I still have 50 degree vent temps but the entire system is new so I should get several trouble free years of operation from it. I did some research and 50 degree vent temps is a common complaint, and its not just Ford. I read posts from Toyota, Chevy, Cadillac, and Ford owners who have complained about the same thing. One of the guys had a brand new Cadillac that had 50 degree vent temops. The common response to all posts was that vent temps between 50 to 60 degrees is considered normal operation regardless of manufacturer. One post from a GM mechanic stated that vent temps could be calculated with ( Ambient Temp - 30 degrees). A vent temp 0f 60 degrees would be normal for a 90 degree day. Thanks to all who posted suggestions on this post.

 

[JUST4FUN]

does the max air work does it pull air from inside the truck.

 

[CVWheeler]

Yes, the recirc works fine.

 

[stamp11127]

If you have a temp gun what is the accumulator temp when running?

 

[buildingdoc]

What is your low side pressure with a 90* ambient? That 30* drop figure they give you is cooling ambient air. so if you are on recirc, and its cooler in the cab, you should see a sub 40* psi on the low side. I started doing automotive ac in 96 and have worked with some of the leaders in the industry. I know it sounds arrogant, but I really am trying to help. At the end of the day I can cool my cab.

 

[CVWheeler]

Sorry for the late reply, my refrigerator went out. What fun. When I get some free time I'm going to try an aftermarket expansion valve and see what happens. If that doesn't work I'll just write it off as bad AC design. I might also try a different brand of 134.

 

[Swetrid]

In my opinion what you are describing is a normal characteristic of the ac system. On a 90 degree day 45-55 degree discharge temp is what we see all day long on most vehicles. Some vehicles are better then others. I miss the days of R12 when you could get 20 degrees and frost out of the ac system.

 

[CVWheeler]

I also have a 2001 F-150 that uses an orifice tube instead of an expansion valve and I get immediate 40 degree air out of the vents when I crank it up. It actually gets down into the low 30's after it runs for a few minutes.
My wife's car is a 2005 Lincoln Navigator that has the exact same engine and AC system as my 2005 Expedition, it too has 50 degree vent temps. I think it is just a poor design.

 

[svfetter]

In my opinion what you are describing is a normal characteristic of the ac system. On a 90 degree day 45-55 degree discharge temp is what we see all day long on most vehicles. Some vehicles are better then others. I miss the days of R12 when you could get 20 degrees and frost out of the ac system.

I agree Completely. Especially about the old R12 days. Those systems worked great.

Today's compressors are much smaller as well. In many cases designed to just barely do the job

 

[Agktown162]

Sub cooling and super heat is the proper way to measure your system. Also fan speed plays a big part in diagnosing.