2002 A/C RPMs for adding refrigerant

Joined
Mar 13, 2022
Thunderbird Year
2002
Hello,
I've been lurking around this forum for a few months. Gathering knowledge and getting familiar with my new to me 2002. So far replaced: pass window motor&regulator, Dr door lock solenoid, spare tire (modified), reconditioned the headlights and fixed an AC leak and charged it. Traded a 91 vette convertible for the Tbird. Hated the vette, love the Tbird.

My question is charging the AC. I have the digital manual with the suction & discharge charts and charged it to 38psi suction on idle, approx 2.75 134 cans and a 8oz oil. The manual states start the process at idle, no mention of rpm after that. I'm used to GM, where you charge it at 2000rpm with charts. At low Rpm it cools, but not cold. My experience is that it's under charged. (I sm ASE and EPA refrigerant certified)

Should I do my usual 2000 rpm, put the suction dead middle of the charts or is it supposed to be done at idle?

Thank you for a very informative forum, and your time.

Don
 

biddle

Forum Moderator
Staff member
Joined
Mar 9, 2003
Please pick a subject that summarizes your post for better responses. "2002 A/C" is vague and could mean anything.

Also, on a side note, if you work on AC systems you know they are supposed to be a closed and sealed system and should not need "charged" so you likely have a leak somewhere.
 
Joined
Nov 3, 2007
Thunderbird Year
2002
Whenever I charge an automobile AC, it is best to recover all the refrigerant, evacuate, and recharge to the listed ounces.

When you cannot do that, I rev engine to 1500 rpm, put fan on high and charge until low side gets to about 27 or 28 psi.
 

jimntempe

Active Member
Joined
Apr 2, 2021
Thunderbird Year
1957
Hello,
I've been lurking around this forum for a few months. Gathering knowledge and getting familiar with my new to me 2002. So far replaced: pass window motor&regulator, Dr door lock solenoid, spare tire (modified), reconditioned the headlights and fixed an AC leak and charged it. Traded a 91 vette convertible for the Tbird. Hated the vette, love the Tbird.

My question is charging the AC. I have the digital manual with the suction & discharge charts and charged it to 38psi suction on idle, approx 2.75 134 cans and a 8oz oil. The manual states start the process at idle, no mention of rpm after that. I'm used to GM, where you charge it at 2000rpm with charts. At low Rpm it cools, but not cold. My experience is that it's under charged. (I sm ASE and EPA refrigerant certified)

Should I do my usual 2000 rpm, put the suction dead middle of the charts or is it supposed to be done at idle?

Thank you for a very informative forum, and your time.

Don

I don't think it matters what rpm you charge at. In my experience it can be difficult to get a full charge in during warm weather if you don't run the engine up to around 2000. But the only thing that matters is getting the right amount of refrigerant in. If the amount in 2.75 cans is what the sticker on the car lists as capacity that's the best you can do. Lots of cars don't cool very well in hot weather at idle. If the car has been baking in the sun it's impossible to get a good idea of it's cooling, esp at idle as all the ductwork and the car itself is cooking at 100 degrees. If the car has been in the shade I'd expect to be able to get air temp at idle of about 48 to 55 degrees (MAX AC settings) after 10 minutes. If you take it out on the freeway vent temps should be somewhere between 42 and 50 at speed. 38 psi suction at idle sounds pretty good to me in warm weather. If you rev it up you might see it drop but I don't know what the settings are for these cars. Most cars seem to have a low pressure cutout at about 34 to avoid icing up the evap but I've seen some go to below 30 before clicking off.
 
Top