A/C Question High Side Low , Low Side High!

[HeroSammich13]

Hello,

1999 Ford Explorer Sport 4.0 SOHC
Car was sitting in the garage for a year, starting it back up in the summer and the AC isnt working. (was perfect prior to storage)

Car Off = Pressures read 100-110 Both low and high side.
Car Warm and Running ===
Low Cycles: 22-65psi
High Cycles: 135-160psi
Ambient Temp 86.5F /// Vent Temp 86.5
4-5 Seconds Compressor runs on
7-8 Seconds Compressor disengages from belt and rests.

Looking for ideas on what to check before I assume its the Compressor failed...

Thanks!

 

[david4451]

Compressor recycling times indicate low on refrigerant.

 

[boominXplorer]

If it's 85 degrees and your getting down to 20 psi on the low side then I'd also say your low on freon.

 

[HeroSammich13]

Well I was just about to add some freon, the ambient temp right now is 108, vents blow at 120.
Plugged in the gages before the car was on and the low side pressure was in the 150+ retard range... Very scary.
Think theres a clog somewhere? I vented a bit of both sides and theres a lot of oil coming out of the high side...

Turned on MAX AC.
Readings:
22-92 low, 175-195 High
After car off they rest at 135 low / 140 high

Probably should have mention the car was low speed, "rolled" on to the driver side before being garage stored. Perhaps a connection was damaged? Im not seeing anything obvious though...

 

[HeroSammich13]

Compressor recycling times indicate low on refrigerant.

Hmmm, perhaps something on the low side is blocking the flow...

 

[radman]

The low side could have a plugged orifice tube.

 

[boominXplorer]

Over 100* the pressures will be extra high. With the system off 150 high / 150 low isn't off by much.

At this point I'd take it to a professional and have them evacuate, vacuum, leak check and recharge. Most places only charge around or less than $100 for this service (My shop charges $75) and will have the right amount of refrigerant in there down to the .001 lb.

 

[masospaghetti]

Sounds like a good opportunity to get some A/C service tools and dig into it yourself!

A manifold set and vacuum pump aren't expensive, and refrigerant is cheap. You'll spend some extra time initially but one visit to the shop will pay for most of the stuff you need.

 

[ranger7ltr]

Hello,

1999 Ford Explorer Sport 4.0 SOHC
Car was sitting in the garage for a year, starting it back up in the summer and the AC isnt working. (was perfect prior to storage)

Car Off = Pressures read 100-110 Both low and high side.
Car Warm and Running ===
Low Cycles: 22-65psi
High Cycles: 135-160psi
Ambient Temp 86.5F /// Vent Temp 86.5
4-5 Seconds Compressor runs on
7-8 Seconds Compressor disengages from belt and rests.

Looking for ideas on what to check before I assume its the Compressor failed...

Thanks!

Ambient temp of 86.5 should give a high side of 199-234 psi... Low side is irrevalent since compressor is not on long enough...Add a few ounces of refrigerant and bring the high side up then watch the vent temps...If the compressor, orifice tube, and cooling fan are in decent shape the vent temps will drop into the 40's maybe the 30's with a clean condenser...But you will need to find the leak and see if there is any air leaking into the system...My Sport runs 37-40 f with the ambient in the high 90's

 

[8TZX]

Also when checking pressures run engine at a minimum of 1500 rpm.

 

[HeroSammich13]

Thanks all,
The low pressure reading high was because of the temps.

I took it to a shop that had free diag, they said it was low on freon.
Added some and shes running cold again. Guess it was my lack of proper protocol, should have done it right. Pull vacuum, check for leaks, add correct weight, then do diag.

Peace~