AC increases temp while sitting idle, blows 60F while driving

[pluto]

Interesting you would bring that up. I did not put oil back in, I pumped the system out a room temp and the car should not been start for over 24 hours, so my thought was it was only Freon being pulled out not oil since is was under pressure of only 85PSI ambient temps
You think I should add oil into the system? How much, like 2 oz? I think Walmart sells a small canister that oil only.

 

[Hamfisted]

Auto Zone sells the PAG 46 in 3 oz. cans.

3 oz can of PAG 46 at Auto Zone


I still say your low side is too high. Try spraying a mist of cool water from the garden hose in the condenser and see if your temps / pressures improve. Could be a blockage in the condenser, but you'd have to pretty much do a FLIR temperature scan of the condenser to see it.






.

 

[pluto]

I can try the water hose suggestion.
Do you know if the freon travels through the condenser in serial or parallel paths ?

 

[Hamfisted]

I can try the water hose suggestion.
Do you know if the freon travels through the condenser in serial or parallel paths ?

Parallel flow ...







.

 

[pluto]

Hamfisted - I install my gauges while at idle ambient temp 95F , Low side 60-62PSI, High side 210-220PSI, in cabin temp 72F~. I started to hose down (not a mist, more low pressure hosing it down) the front end through the front grill. I did that for about a minute, walk around the window to see my temp gauge, temp did drop after 2 minutes, but also the gauge really dropped
1) Low side 42PSI, High side 150PSI, in cabin temp started dropping to 62F~
2) started to rev up the truck to 1000 rpm for ~1 minute , Low side 38PSI, High side 170PSI, in cabin temp 60F~
3) started to rev up the truck to 1500 rpm for ~1 minute , Low side 30PSI, High side 180PSI, in cabin temp 58F~
These number look a lot better due to the hosing down the front end thru the grill. Not sure if the water caused some pressure expansion and release of internal clogged with temperature change (thermal expansion). By this time I needed to run in for a conf call at 8pm, I will test again tomorrow mid morning once the ambient temps hit 90F or higher.

Hamfisted , check this out . Prior to doing above tests, I noticed the suction line from the condenser to the front expansion valve has a "Y" (front and rear AC units). The Y section going to the rear ac is cold, the section to the front expansion valve is warmer with the front AC on. Not sure why the this .I turned on the rear AC, that section of the suction line started to warm up to match the other Y section. At this time the cabin temps were 72F after 10 minutes of idling the truck with ambient temp 95F , Low side 60-62PSI, High side 210-220PSI. At first I was thinking, there is clogged in the evaporator cause I replaced the Expansion valve already. Bu that did not explain the reason for the suction line temp to increase once I turned on the rear AC. I would of thought the rear ac suction line would get colder. I that point I was confused and moved on to your hose test which I'm glad I did

 

[Hamfisted]

Why did you replace the compressor originally ? Did it come apart ? If so, debris may very well have gotten into the condenser and partially clogged it. These parallel flow condensers clog very easily and are generally replaced anytime a compressor sends it's debris into the system. Their passages are very small, and they're almost impossible to flush out adequately to continue in a refurbed system. Your pressures appear to improve dramatically when you sprayed water onto the condenser.


Condensers at Rock Auto


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[pluto]

I replaced the compressor last year for the same issue having today, the new compressor improved and helped maintained temps in the mid / upper 60F while in traffic but this year the heat here is TX has been very high and very early in the year. This year it would not maintain below 70F, climbs more quickly to 85F and above while in traffic (stop and go situations). The old compressor once removed, oil was clean, but I could turn the pulley very easily, seems to have lost compressor. I still have and thought about a local rebuild, The replacement compressor was purchased from RockAuto along with expansion valve front (installed recently this year) and back.
I will continue to monitor the ambient temp Vs Cabin VS Low/High pressures
Thanks for the dialogue and ideas, when I go into it again I will replace the Condenser, remove the expansion valve and blow out the evaporator lines all the way to condensor and see what comes out . thats alot of work (take apart the front end) and trying to avoid , will see how it goes in the coming weeks once parts arrive

 

[Timo2824]

I'm going to throw this out there, as a former ford mechanic and current HVAC professional, take it to a shop. You're throwing parts at it and don't know what you're doing. If the system doesn't have enough oil in it, you'll destroy the compressor. If you put too much oil/leak dye in it, you'll coat the evaporator and condenser and never get the correct heat transfer from it. The system charge weight is for a vacuumed system, that's at 500 microns or less which takes special tools to measure. If your evaporator or condenser is clogged, you'll never get good numbers because of low airflow/heat transfer. If you're condenser fan isn't pulling enough air you'll never get correct numbers. Your problem sounds like low airflow/heat transfer across the condenser. But it also sounds like you purged your charge to atmosphere and didn't pull a vacuum on it before dumping 3 cans of refrigerant in it. So it's probably overcharged and has moisture/none condensables in it as well.

 

[Matthew Jenkins]

Did you solve this issue? It sounds like the second fan is not turning on or spinning fast enough at idle to pull enough air across the condenser. Spraying water on it will do the same thing. Driving will put air across it. You only need that fan at Idle.