Automotive Air Conditioning Information Forum

Hello and thank you for the platform here to ask questions

2008 F350 quad cab XLT lariat

The basics......

Removed cab to replace high-pressure fuel dist everything original had this truck since brand new

System was perfect before so I am trying to get it back there again but I did put new parts in the a/c system while it was apart along with all o rings and "seals" the flat aluminum style

New receiver dryer
New condenser
New motorcraft compressor
New orifice tube (in the correct direction)

Did not flush the system it was clean and no sparkles
Blocked off all open lines while storing for cleanliness

Re installed everything
Added as close to 6oz of oil as I could measure
Pumped down to 28 held for 45 min no prob
Let vac run for about another 30 min

Here is where I keep getting misinformation
Truck sticker says 27oz
The crazy internet is all over the place with some saying 37-42oz !?!?

Got two cans of 134a at Wally 14oz cans for a supposed total of 28oz

Opened low side it took the first can no prob took about what seemed 2 min and a few cycles
Lost just a small burst from the second can when changing the silly new blue non puncture adapter but nothing huge
Truck took second can quite faster in what seemed one or two long cycles

It sweats and gets "cool" but not like she used to

No official mechanic but nobody works on my stuff but me unless it's on the machine shop level
Electric contractor by trade Truck nut by birth so I don't know what these numbers should be at

Compressor engaged
High side 250ish
Low side 45ish

I hope this is a simple fix truck has ran no more than 2 miles or 25 min since the charge was shot to it

Any help would be greatly appreciated if advance

What is the ambient temperature for those pressures?

Was this at idle or 1800 rpm?

Which engine in this truck?

Revisiting your topic, albeit a little late.

bohica2xo wrote:What is the ambient temperature for those pressures? Was this at idle or 1800 rpm? Which engine in this truck?

Answering these questions will be very helpful in diagnosing this.

Also, a few additional questions and observations. If the under-hood sticker specifies 27 ounces of R-134a, then that's what you should go by. The sticker always supersedes A/C specs found elsewhere. Did the sticker also specify 6.0 ounces of oil? PAG-46, or something else? If so, you might have overcharged the oil slightly if you didn't replace the evaporator. I don't think that'll be a problem, though. A bit too much oil (within certain limits) is better than too little.

Hopefully, the refrigerant you used was pure R-134a without any sealer or other additives. Sealer in particular can clog-up a system, leading to additional costly repairs and/or parts replacement. Also, it would have been much more accurate to weigh-in the charge using a refrigerant scale rather than approximating the charge using the small cans.

Lastly, if you're located at sea level or close to it, you should be able to pull a vacuum of at least 29.9 inHg using a good vacuum pump with fresh oil in it. A vacuum of only 28 inHg isn't sufficient for removing all the air and moisture from the system, especially if you run the pump for only 30 minutes. You need to evacuate the system for at least two hours at 29.9 inHg or better. So you probably sill have some air and moisture remaining in the system, which will compromise cooling.