And yet another A/C question.....

[REM3200]

Car is stock,AC works fine once the car is moving for a bit (converted to 134a two years ago). Today, here in the DFW area it is 92 degrees and 67% Humidity. Car has been sitting out at Starbucks under a partly cloudy sky for 30 minutes. When i start the car and turn the air on luke warm air comes out (it's on MAX) when the car is moving it will slowly get colder and colder--all this takes several minutes and if I hit a stop light it will begin to put out not so cold air; as soon as I get moving again the air gets colder. It will take a full 7-9 mins to get the car cooled down assuming no more traffic lights. Once it gets cooled down it's fine--air is nice and cold--but--all this takes quite a while to happen.
In contrast, my 2001 Nissan pick up will throw out cold air the second you turn the engine on, no matter what the conditions are. I realize the 20 year old Buick will not do this but I seem to remember that GM had pretty good AC in 1987. Was it just the R12 that made the difference??? My question is this--what's it going to take to get cold air out of this AC at a stoplight on a hot day two munites after I turn the system on MAX???
The car runs at 180 w/ AC on--fan is running on high when AC is on. Has a 180 thermostat.
Any thoughts would be appreciated. By the time the car cools down i'm already home !!!

 

[phillyturbosix]

First thing I'd do is get that 180 stat out of there and put a 160 in. These cars heat soak fast in the summer and all the help they can get is always good! It sounds like you might be a little low on freon. These cars are 20 years old and all the parts for the AC system are old and prone to a little leak here and there. The thing with 134 is the amount of 134 in the system has to be dead on. If you have too much or too little you'll see the symptoms you have. Where R12 you can add a little more and it will get colder. That's why allot of the "old heads" say that 134 can not get as cold as R12. Well it can and get colder! My GN is like an ice chest and I run 134. The key is the level has to be dead on. Change that T stat and take it to a good shop with the proper equipment to make sure you have the proper level of 134 and you should be fine. Also keep in mind the Buicks have the duck work for the vents up higher then most new cars. So when that sun has been beating on the dash your vents can be way over 100 degrees. So it takes some time just to cool down the vents. Allot of the newer cars they moved the duck work down much lower so the ducks are not on fire when you fire up the AC. Good luck with it and report back!

 

[Roc87]

When MAX A/C is on, you'll pulling air from inside the car to cool, rather than outside air. Drop the windows, run regular a/c for a bit, then roll up the windows and switch to max once the inside of the car has cooled down a little, should help a little bit, in addition to what Jim said.

 

[pacecarta]

possible problems

leaking hvac vac lines in the engine compartment
do you still have the vac reservior ball under emmisson cannister?
is hvac check valve at rear of driver valve cover (black with three ports) functioning properly
the system could be leaking out the stored vaccuum and allowing the fresh air door to reopen when car is turned off
is the cowl seal inplace ? this will allow underhood heat to be drawn into car

check that the heater valve is closing fully (its behind pass valve cover ), if its stuck open youll get hot water circulating through the heater core

check that the heater door is functional and that arm that the cold/hot cable connects to isnt broken (you can drop glove box down and look ), and that its adjusted properly to close door when in cold position

and im with Jim , 134 works , i see 34-36* at the ducts

 

[oddfire6]

also make sure your fan is running when the a/c is turned on....

 

[turbo96max]

dam someone should open up a gn ac shop. bc i have sealed the vent bc it was not closing properly. eliminated the heater valve to make sure that its not mixing. added a condenser pusher fan, and the car will cool alittle bit driving, but once i hit a stop liht temps just rise again. and once the car get hot like its been on in the sun for a while )about an hour or more, forget about it, wont cool for nothing in this world. its running 3.2 lbs or r12(real deal) .the car also get hot in my case, runs about 215, so i am ordering dual fans to see if that will help.

 

[Nick Micale]

Car is stock,AC works fine once the car is moving for a bit (converted to 134a two years ago). ....... It will take a full 7-9 mins to get the car cooled down assuming no more traffic lights. Once it gets cooled down it's fine--air is nice and cold--but--all this takes quite a while to happen.
In contrast, my 2001 Nissan pick up will throw out cold air the second you turn the engine on, no matter what the conditions are. I realize the 20 year old Buick will not do this but I seem to remember that GM had pretty good AC in 1987. Was it just the R12 that made the difference??? ...... !!!

First, you need to realize that 134a is only 80% efficient as R-12.

Second, in 1987 no 134a exsisted, and the AC systems were not designed to work efficiently with it. When 134a was universally adopted in 1994 by automakers in their new cars, the systems were designed with bigger evaporators and condensers, as well as compressors to work with the higher pressures. And, of course, they also used barrier hoses made for 134a.

Third, comparing AC in a Nissan PU to a G-body system is not applicable, as the smaller compartment of the PU, and entire system distribution is different.

A properly operating AC in a G-body car will cool down very quickly, stay cool at stoplight and have more than adaquate cooling in 110 deg. temps. This will not be the case with a 20 year old, 100K mile compressor or with 134a. The cooling system MUST also be in excellent working order.

Not for those doubters that say "my 134a conversion works great", bring your car to the desert for a few days as we will be having 110 deg. temps through the weekend, and you can dispute me here.:biggrin:

 

[turbo96max]

First, you need to realize that 134a is only 80% efficient as R-12.

Second, in 1987 no 134a exsisted, and the AC systems were not designed to work efficiently with it. When 134a was universally adopted in 1994 by automakers in their new cars, the systems were designed with bigger evaporators and condensers, as well as compressors to work with the higher pressures. And, of course, they also used barrier hoses made for 134a.

Third, comparing AC in a Nissan PU to a G-body system is not applicable, as the smaller compartment of the PU, and entire system distribution is different.

A properly operating AC in a G-body car will cool down very quickly, stay cool at stoplight and have more than adaquate cooling in 110 deg. temps. This will not be the case with a 20 year old, 100K mile compressor or with 134a. The cooling system MUST also be in excellent working order.

Not for those doubters that say "my 134a conversion works great", bring your car to the desert for a few days as we will be having 110 deg. temps through the weekend, and you can dispute me here.:biggrin:

so you think that if you want the car to cool properly , at a stoplight and all. people need to put a new compressor and condenser, fill it with r12 and then it will work. a 100k mile compressor wont cool the same ????

 

[Nick Micale]

If your car is not cooling well, it could be the compressor, as well as other items. An AC tech can easily find out how well the compressor is working by connecting a gauge set to the car.

Most of the original compressors I have dealt with lately are well worn, and not pumping down like when new.

Condenser should be fine if not clogged with debris.

 

[Scott Atk]

Probably just needs topped off. Do you have Ramcharger or SPAL dual fans?? The fact that it gets warmer at stoplights is a result of reduced condenser airflow. More efficient fans will help. For those that have converted to 134A, I believe there is now a "parallel flow" condenser available for our cars. That will help also.
Also if there is anyone near Vegas that needs help, I have plenty of R12

 

[turbo96max]

actually the car get hot with the ac on. so i just ordered the dual fan set up from gbodyparts.com. will see how that helps. gauges showed pressures climb due to heat, then when pressure was released it started cooling down.

 

[BlackBandit]

You can get the same temps with 134 as you do with r-12, you just have to work the system harder to get them. If everything is right and working properly you can play with the switch on the evap canister (set screw between terminals) and adjust the turn on pressure for the compressor.

 

[Nick Micale]

You can get the same temps with 134 as you do with r-12, you just have to work the system harder to get them. If everything is right and working properly you can play with the switch on the evap canister (set screw between terminals) and adjust the turn on pressure for the compressor.

Maybe you can get the same temps in Michigan or San Diego, but with our temps here in the desert, you will blow that original compressor apart!

You need 20% more pressure for the same temp as with R-12. I have trashed all the ones that have come apart, so no pics to show you. We have seen operating presures well over 400 psi.There is a BIG difference when temps get over 100 deg., and we have to make sure the cars still operate and cool at 110+.

The new replacement Delco compressors are made to handle 134a and their higher pressures, but the 20 year old ones [the few still around] are having a hard time with R-12.

I am always willing to learn new stuff, so if you visit Phoenix soon, show me how it is done.:biggrin:

 

[Roc87]

I can't imagine trying to have A/C on a 20+ year old G-body in Phoenix, It's hard enough keeping the elky from climbing above 220 with dual fans, at around 98 degrees........and not having to deal with an intercooler.

Best of luck Nick, Heard it was over 115 there the other day

 

[Nick Micale]

......Best of luck Nick, Heard it was over 115 there the other day

You heard right, but we expect a "cool spell" over the weekend, it is supposed to be under 110 deg.!:biggrin: