A/C recharging question

[dcarlson]

how do I recharge if they want A/C running when you charge it but engine lid must be closed for A/C to run? Am I misinterpreting something or just a complete idiot? (ignore option 2).

[kuehl]

Without going into the complete details of how to charge a system:

"car parked on flat ground, trans in neutral, parking brake on, doors and windows closed, fan speed switch on 1,2 or 3, thermostat on max cold (CW), with your service
gauge set hoses connected to the compressor, the hoses should be routed to the RH side corner of the engine compartment to avoid the compressor clutch pulley cutting the hoses; (standing behind the car RH is right!), and duct tape the hoses down so they don't move, ...... gently rest the engine deck lid down so it comes to rest on its stop or the hoses...... do not slam the hood down on the hoses, do not try to push the hood down all the way or you will crush the hoses and have a very very very very hard time trying to release the hood latch later (ask me how I know this.. lol).
DO NOT SLAM THE HOOD DOWN ON THE HOSES".

If your a newbie to charging, only charge by gas (can upright) through the suction side. Again, just a brief warning. Complete details are posted all around the forum.

The reason you have the deck lid down when charging or testing is so that the engines cooling fan is pulling air through the deck lid condenser as best as practical (there will be gaps around the engine deck lid and surrounding body panels. If the deck lid was up when you were charging or testing then no air would move through the deck lid condenser, the system pressures would rise and that is not a perfect world.

[dcarlson]

so it is doable - good show. Thanks very much. I've charged other cars, but always had charging unit visible so I could read pressure gauge on the unit. I'll do search here to get all details..

[mkc1962]

A method I use, and it works great with the lid up.

I drape two nice soft towels over the rear hatch top lip and lower base near the rear window (not covering the cowel, leaving it fully open) so as not to scratch anything

If one has concern of the towels falling in toward engine bay and rotating members, one could tape the edges of the towels down. Personally I have never had a problem.

I then place one of those cheap/light $10 box fans, facing the cowel so as to blow across the condensor on top of the towels. Turn on high.

Proceed with charging.

[dcarlson]

it worked out fine - got a recharge kit that featured a long hose - let me close the engine lid on it without issues- blowing cold..

[hyperkinesis]

thanks for the info .... what the ideal preassure doe my 1984 911 with a R134a system?
exterior tem are around 95 degree F
some friend told me that in low rpm no mre than35 and in 2500rpm no more than 200.. more than that it posible to breaks any seal thanks correct??

[Bob Kontak]

Originally Posted by hyperkinesis

some friend told me that in low rpm no mre than35 and in 2500rpm no more than 200.. more than that it posible to breaks any seal thanks correct??

Griff (Kuehl) knows best but the numbers you are quoting make no sense at all from what little I know.

There is a suction side and a discharge side in your system. Suction is before the compressor and discharge is after the compressor. They are also known as the low and high side.

The high side is roughly two times ambient temperature plus 50. That is 240psi at idle on the high side. If you rev it to 2500 in your driveway what is going to make the pressure drop? The big engine fan kind of sucking air through a kind of closed engine lid? You also have no air passing over the front condenser other than the front factory fan.

Look for 240 high side and 45 low side at idle.

[hyperkinesis]

thanks

ok the high and low in low 30 and high 200 for a ext temp of 95F that what I have now and the air is fresh but not cold.... I ask 2 friends that know about air conditioning and they said that more than 200psi is a risk because it can break seal and damage somehing else...
I read here other think people here gost to 240psi in high without damage something

and sear few charts and one said at 100f = 125 psig and others

Low Side Readings =25-43psi Evaporator Temperature (Fahrenheit) =40-65 High Side Readings psi= 165-270 Ambient Temperature (Fahrenheit) = 90-100

[Bob Kontak]

Originally Posted by hyperkinesis

I read here other think people here gost to 240psi in high without damage something

I viewed 425 on an 89 turbo and there was no damage. It was not functioning correctly but there was no explosion or failure. Calm down.

I think you just need a little more R134. Best thing is to evacuate system pull a vacuum and add the exact amount you are supposed to have.