MikeThomas

So you think its hot where you are??? It was 116 yesterday here in sunny Phoenix . My AC works fairly well except when I stop. Im guessing it is from lack of airflow over the AC coils... so the idea is to get a junkyard electric fan to keep the air moving over the coils when stopped. Has any one done this, and if you have, how have you controlled the fan? I would like it to be an automatic thing, but i am not sure how I could rig up a normal temp switch with the coils....any ideas?

wannadiesel

Hot rod shops like Summit and Jeg's sell fan controllers that use a temp sensor that just lays in the fins of the radiator.

I would just use a relay and run it off the A/C compressor circuit. When the compressor is on, the fan runs.

simplysmn

It's 115 here right now in high desert of calif so I know what ya mean about hot yukkkkkkkkkkkkkkkkkkkkkkk and summer just started holly smokes are we in for it this year.

Bill Tomlinson

I strongly suspect that the loss of cooling at idle is more due to an unfortunate gearing choice. The compressor needs more rpms to make things happen. Also... the fan does help as I have one and it improves performance in stop and go traffic and at idle. Step up your idle a bit. Make sure your thermostatic fan clutch is working. Sometimes a diesel does not make enough heat to engage it enough to pull a lot of air through the condensor. I am looking at getting one of those great big silver accumulator tanks like newer vehicles have. I find working on the compressor and it's lines a major pita because of the location. I have a better compressor than the one currently on my truck, from a Dodge car of similar vintage. One flange must be ground down for it to fit properly. Two condensors from mini van's hook up to the stock setup (a little creative plumbing is needed for the second one) and two mazda pusher fans will keep it cooler. The one's I found just fit under the grill (non-IC'd) I am going to switch to the better rad ASAP. Oh yeah, propane, or HC as it is called commercially is a superior refrigerant medium. Better even than the old r12. I can get temps of minus 8 Celcius at the vents. This does not happen in stop and go traffic, only on the open road or just at start up.

BearKiller

That's better than the ice-cream truck.


What purpose does the silver accumulator tank serve??

whereswaldo250

I feel your pain Mike, I also have the same problem when I stop my mirrors start shaking like there is an earthquake. I thought that it was a major problem. So there is no way to fix that, just keep that rpm's up????

MikeThomas

Yeah, probably need to bring the idle up Ben, I do too . Just a turn of the screw.

Jim Lane

An auxiliary condenser fan is a good idea for low speed cooling; I would connect it in parallel with the compressor coil through a relay.
Most condenser fans start as soon as the AC clutch is engaged besides for the fact most of the ones you see are on front wheel drive cars with traverse engines that have the radiator and condenser on separate sides of the core support and no engine driven cooling fans.

But to use it for auxiliary cooling I would connect it so it was always on with the AC.
When you do a R134a conversion it is recommended on cars that have a single fan to have the cooling fan all of the time anyways to help with the high head pressures it will encounter from sitting in traffic with no air moving through the condenser.
Why do you think the mechanic has to put a big fan in front of the car when they charge the AC?

Also check your idle speed might be a bit low,
Check your fan clutch, although it is not in lockup it still has to have some resistance to give some cooling at low speed.
Check the front of your condenser and make sure it is not blocked with suicidal bug bodies...
Make yourself a wand out of 3/8 copper tubing bent 90* at the end and connect it to your garden hose nozzle.
The trick is to pressure wash the fins back foreword from behind the fan to the front of the truck and hose out all of the bugs.
Jim

Bill Tomlinson

I am not positive but I think they help keep things stable when in stop and go traffic. I also suspect that they were not needed on the old R12 setups. Anything that makes R134a work better has got to make AC better.

By the way, I just blew a gasket on the compressor where the metal connectors are. This time I swear I am going to get it right!

andyr354

I have problems with mine when stopped. If I let the AC run for more than a minute or so while not moving the high pressure valve pops open on the compressor. I assumed it was due to some problem I don't know about or to little airflow through the condenser along with 134a.

Santaclaus

I think that tractor trailer have some sort of pressure switch that activate the fan clutch. The International's, seem to get sort of warm and then the fan will kick on.

Mike