Automotive Air Conditioning Information Forum

hi all,

first time poster. been fighting poor idle cooling on my 2002 7.3 for months.

ford
2002 F-250
7.3L engine
R134a
without aux air

began with warm air due to evaporator leak, have taken the following steps:

1) new evaporator
2) new suction accumulator
3) new (fixed, 0.056") orifice tube
4) new condenser
5) new compressor (found slight debris on old orifice) - air gap set to 0.022"
6) flushed only remaining lines/manifolds
7) 9oz oil added (per sticker on radiator support)
8) 1hr vac, 30 min add'l pump off (no movement)
9) recharged by weight (30lb tank r134, electronic scale).

spec weight (without aux AC) per sticker on radiator support is 2lb10oz, i recharged to 2lb12oz to allow for 2oz of line loss in my gauges and hoses.

after all of the above, @95 ambient, ~60F air at idle, ~39/40F at speed. idle and 1500rpm suction and discharge pressures are 'in the range' per ford factory service manual.

i replaced the fan clutch as a last ditch, unfortunately my new unit was bad out of the box (would not unlock). i am awaiting the warranty replacement. however, original unit can be heard at startup, and is stiff to move when engine off. do not suspect it to be faulty.

any advice?

i have found 1 or 2 references on ford forums about the refrigerant capacity being updated ~8oz lower due to an updated microchannel condenser design - does anyone have accurate/current charge specs for this system that differ from 2lb10oz?

If you have to face any problem, you need to contact an Air conditioning expert which gives you the solution to this problem.

Your upset with 39-degree air?

Tim wrote:Your upset with 39-degree air?

Definitely not, 39 rocks. Upset with the 60-64F at idle.

zj96sc wrote:

Tim wrote:Your upset with 39-degree air?

Definitely not, 39 rocks. Upset with the 60-64F at idle.

39 degrees is great !!

At idle, lower rpm, plus you need that cooling air flow, try the new fan clutch; makes sure all shrouds are there and that condenser fins are clean.

"after all of the above, @95 ambient, ~60F air at idle, ~39/40F"

39f rolling down the road, 60f stopped. AIRFLOW.

Bad Fan Clutch. Missing shrouds, seals or air dams.

On a cold start, the fan howl @ 1500 engine RPM should be awful. After idling with the A/C on, both doors open & cabin fan on high for 10 minutes the fan should howl just like it did when cold.

Just because the engine does not overheat, it does not mean the clutch is OK.

Expect to pay north of 100 bucks for a clutch on that 7.3 - the $50 white box Chinese special may not even work as well as your worn out one. I think the OEM clutch is about $180 right now, and a Hayden aftermarket part about $115

Your "bad" clutch - was this a chinese white box item?

I know of only one condenser for that model year range - the standard parallel flow OEM. Same part from 1999 to 2007

Tim wrote:"after all of the above, @95 ambient, ~60F air at idle, ~39/40F"

apologize if i was unclear, was trying to say:
@95F ambient, i get:
~60F air at idle (unhappy)
~39/40F air at speed (happy)

bohica2xo wrote:39f rolling down the road, 60f stopped. AIRFLOW.

Bad Fan Clutch. Missing shrouds, seals or air dams.

On a cold start, the fan howl @ 1500 engine RPM should be awful. After idling with the A/C on, both doors open & cabin fan on high for 10 minutes the fan should howl just like it did when cold.

Just because the engine does not overheat, it does not mean the clutch is OK.

Expect to pay north of 100 bucks for a clutch on that 7.3 - the $50 white box Chinese special may not even work as well as your worn out one. I think the OEM clutch is about $180 right now, and a Hayden aftermarket part about $115

Your "bad" clutch - was this a chinese white box item?

I know of only one condenser for that model year range - the standard parallel flow OEM. Same part from 1999 to 2007

-- shrouds seals and air dams per OEM spec to my knowledge. will review parts catalog to be sure. can provide pics if you are familiar with the platform.

-- cold start fan howl @ 1500rpm - check, makes tons of noise. goes away after 3-4 min of driving.

-- fan howl using only A/C - does not occur that i can remember.

[suspected] bad out of the box was a new motorcraft clutch from rockauto. did not unlock at any speed, engine temp, ambient temp, rpm, or drive time. had it on for ~50 miles. actually forced belt to slip on water pump pulley at high rpm.

for the sake of completeness, here's some temp/pressure data from just now:

ambient: 82F shade, 87F on truck overhead console

A/C off: 75psi both sides

idle: 160/34 to 175/35 over time, vents = 56F

1750rpm: 250/30 to 230/27 over time, vents = 44F

idle plus water hose on condenser: 125/20 and tripped low pressure cutoff. vents 48F.

"1750rpm: 250/30 to 230/27 over time, vents = 44F" Sounds pretty good. Will be cooler when actually driving.

Verify the recirc door is fully closing along with heater control valve operation.

Vent discharge 30deg under ambient in non-recirc mode rings a bell as "normal" on most systems... which is where you are at idle. A partially open recirc door will often cool at highway speed but not slow/stopped.