R134 A/C runs a little hot, I think?

[Buick Beginner]

Gentlemen,
The previous owner/abuser of my 87 GN had the system converted from R12 to R134. Fortunately for me when he did this he also had a 4 core radiator installed, probably a reconditioned one since it's all black and pretty. Anyway, he said the system runs a little hotter with the R134, so he also installed a "pusher" fan on the front of the condenser. When I turn on the A/C and the pusher fan the car blows COLD air but my temp gauge goes from a solid 180 to a solid 215 in about 3 minutes flat. I've already got a 160 thermostat installed, and my chip kicks the fan on at 175, so with that in mind, am I running hot? I live in Florida and it's been around 85 degrees during the day so far. When the A/C goes back off the car cools to 180 again in about 4 to 5 minutes. Am I normal? - BB

 

[GN-231]

You need to seal the shrowd on the stock fan to achieve better airflow through the radiator. Take a look at how fan off the radiator the OEM fan is mounted, you will be suprised. You lose a ton of airflow due to having no seal. I am going to seal mine up before it gets too hot this summer. Ramcharger sells a fan shrowd sealer kit, but you can probably get away with some kind of weatherstripping from HomeDepot or a junk yard.

A 4 core radiator should help, maybe the 4 core he installed has a lower fin per inch density.

"black and shiney".....If someone paints a radiator with the wrong type of paint then it will have terrible heat transfer characteristics. You need special pain.

The pusher fan maybe choking off the airflow, I would take it off. He should of gone to a dual SPAL fan set up if he was having problems.

Don't konw about your 134a question, but it sounds kind of fishy to me.

 

[Steve Wood]

R134a is less efficient and the condensor runs hotter which means more hot air is being pulled thru the radiator.

The pusher fan may be blocking airflow....I would try it with out the fan in place...be sure that the shrouding in front of the radiator along the bottom and up the sides is in place...sometimes people pull that off and the air coming thru grill then goes out the bottom in front of the radiator and around the sides rather than passing thru the radiator.

Don't worry about the paint...Tony DeQuick says that is more folk lore than actual fact and he powder coats his stuff..He is a professional in the field and has tested such stuff.

I always heard the paint for radiators had to be special..he says no...just not on so thick that it impedes airflow.

 

[Buick Beginner]

Thanks Guys

I appreciate the replies! - BB

 

[salvageV6]

I would stick one of those air conditioning thermometers in the middle vent with and without the fan idleing in the driveway.

Prolly 5 minutes for each setup and record the numbers.

See what the discharge vent temps. are as that helps determine if the system is working properly.

 

[Intercooler]

IMO 4 row radiators are no good. It makes it that much harder to move air across them. A good hi-eff 3 row with 5/8" tubes is much better. Sealing it up and removing the pusher will help a bunch.

 

[MBR87GN]

I live here in Brandon as well ,my car has the 134 conversion and never sees above 185 deg.w/AC on in traffic-I have the factory radiator and cooling fan with 160 deg. thermostat.

 

[Ellis]

In what sense?

Originally posted by Steve Wood
R134a is less efficient and the condensor runs hotter which means more hot air is being pulled thru the radiator.

If you follow treat each as an ideal gas, they are gonna exhibit really similiar responses to changes in pressure and temperature. R-12 is denser, but R-134a has a higher gas constant. I keep hearing conflicting reports as to which is better and why. I have converted a few R-12 systems to 134a, and haven't had any issues yet. The A/C in my Jimmy only blows 53°F on a hot day out, but that's mostly due to the compressor being on its way out. None of the vehicles picked up any higher coolant temps as a result of the conversion.