1997 1fz-fe a/c problems

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Jul 9, 2010
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Location
Las Vegas, NV
I have recently installed a new compressor, drier, and expansion valve in my 1997 cruiser. Recharged the system with 2 lbs of 134. I cannot get it to blow cold air. The temp of air coming out of the air ducts inside cab is 70 degrees at best. It doesn't seem to have a leak in the system that i'm aware of the manifold gauges say there is 30 lbs on the low side and about 300 on the high side. However the site glass on the line is a cloudy white while the compressor is running and appears to have small bubbles in it........Could this be the cause? Thanks for any help.
 
... The temp of air coming out of the air ducts inside cab is 70 degrees at best. It doesn't seem to have a leak in the system that i'm aware of the manifold gauges say there is 30 lbs on the low side and about 300 on the high side. ...

What is the ambient temp/conditions? Do you have good airflow through the condenser? What happens to vent temp/high side pressure if you mist the condenser with water?
 
Howdy! Did you evacuate the system before adding the freon? Got to clean all the nasties out before putting in the good stuff. John
 
Thanks fellas,
The temp outside here is between 100 and 105 degrees. I haven't tried running cold water over the condenser yet....didn't think of that, but i will. It seems like there is nothing blocking the airflow to the condenser.
We did vaccum the system before adding the freon although I don't remember how much vacuum we actually pulled.
I don't believe I know What the coolant mixing valve is and where exactly it is located. is it in the cab or on the other side of the firewall?.
Thanks again for the help!
 
It's on the firewall behind the intake.
 
When I see high vent temp and high side pressure, the first thing that I look at is condenser cooling. If it's insufficient will cause this problem and is the easiest to test and repair. Add additional cooling, spray with water across the whole face of the condenser (no need to drown it) or use a powerful fan blowing directly into the grill. Allow the system to stabilize with the additional cooling for a few minutes, then recheck gauge and vent temp. If they fall significantly, most likely you have found the problem, if not time to look at other things.

In our experience the best way to solve this is improving the main fan, clutch. For a rig that lives in a hot, dry climate, you need a FAN and there isn't an off the shelf replacement clutch that will do it. It needs to be strong and be biased towards great idle/low speed performance. The best way is to change the fluid in your clutch to a much higher viscosity, this will net a measurable improvement at the vent.

Also all of the airflow devices are important for low speed performance. The foam seals around the radiator, hood to core support seal, tin plate under the radiator, fender skirts, etc. They direct, control airflow, if missing A/C performance will suffer and we need every degree that we can get.:hillbilly:
 
Thank You!
After applying a little water over the condenser the high side dropped to 150 and the low side to 20psi. The vent temps came down below 40 degrees....... I'll go check all the seals and what not around the radiator, but what is my next move? Does this mean the condensor is bad? Or do we need a new fan clutch, an electric fan or what? Unfortunately my garden hose won't reach around the block!;)
 
... Recharged the system with 2 lbs of 134. I cannot get it to blow cold air. ...

2lbs by weight or 2 cans? IIRC the fill is ~30 oz, on a 134 system I start slightly under charged, then add an oz at a time until I find the happy spot.

Thank You!
After applying a little water over the condenser the high side dropped to 150 and the low side to 20psi. The vent temps came down below 40 degrees....... I'll go check all the seals and what not around the radiator, but what is my next move? Does this mean the condensor is bad? Or do we need a new fan clutch, an electric fan or what? Unfortunately my garden hose won't reach around the block!;)

Sounds like the typical low airflow over the condenser deal. My first project would be changing the fluid in the fan clutch. Different clutches have differing searing characteristics, post a pic of your clutch and will make a guess on where to start with fluid.
 
I put two 12 oz cans in it. Same as 2 lbs by weight right?.......
Another thing i was wondering about was if we had a lack of airflow coming across the condenser , then what about going down the freeway at 70 mph? I have the same problem whether idling or going fast down the road.
If I can't get airflow at 70 mph, is adjusting the fan clutch oil going to have any impact? Just Wondering? I will post a picture of the fan clutch asap.
Thank you for your help.
 
I also tried blowing additional air through the front of the condenser with a big fan and it did nothing to the high side pressure and vent temps. The real big change came as soon as I added water to cool the condenser as I previously mentioned.
 
I put two 12 oz cans in it. Same as 2 lbs by weight right?.......

Nope, it should have 24oz in it. Most likely needs another 1/2 can, but need to get the cooling under control first. 134 expands with temp more than R12 does, so the sight glass is worthless outside of a narrow "ideal" range, (75-80F?) ambient.

134 systems are picky about charge amount, The best way to charge is by weight, I modify by also by checking performance. I set the motor to run at ~1500rpm, A/C & fan to max, doors open, put a thermometer in the center vent. Undercharge to ~26-27oz, check vent temp, add an oz, repeat, until your happy with pressure/vent temp. If the vent temp starts going up, you have gone too far. In hot conditions 134 systems usually perform best slightly under charged.

Another thing i was wondering about was if we had a lack of airflow coming across the condenser , then what about going down the freeway at 70 mph? I have the same problem whether idling or going fast down the road.
If I can't get airflow at 70 mph, is adjusting the fan clutch oil going to have any impact? Just Wondering? I will post a picture of the fan clutch asap.
Thank you for your help.

I also tried blowing additional air through the front of the condenser with a big fan and it did nothing to the high side pressure and vent temps. The real big change came as soon as I added water to cool the condenser as I previously mentioned.

It should be slightly better cruising than stopped, but experience has shown that the '80 is fan dependent. In other words needs the fan for good performance in hot conditions, even when cruising.

The fan I use for the test is a carpet drier, IIRC ~5000cfm squirrel cage, puts out a focused stream of air, powerful enough to blow through the coolers. Most any blade type fan, probably isn't going to cut it, you should feel a big increase in airflow at the engine side fan when turned on. In any case, it doesn't matter, the water test confirmed the problem.

I can't see/feel you setup, so am guessing. It's possible that the condenser is packed full of bug guts, but that is rare in a desert rig. By far the most common root problem is an under performing fan clutch.
 
Ok, Here is a picture of the fan clutch.
0712001948.webp
 
Hard to tell from the pic, but looks like the original Eaton, if so I would empty and refill with 15K fluid. How does it feel now, like after a heat soak?
 
Ok, I will pull the fan off this weekend when i have a little more time..... then how do I know where to put the oil? Is there a drain plug or something obvious? Sorry for all the goofy questions, all this is very new to me however i am learning alot.
 
My vent temps also rise a considerable amount at idle and slow speeds but cool nicely at speed and with a water mist on the condenser.

My next step is a fan clutch fluid change.
My question is what viscosity of fluid should I buy, 10k or 15k and where can I find the fluid?

Thanks!
 
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You fill the system until the sight glass clears up when the compressor is on. You may see a few bubbles here and there but it shouldn't be cloudy.

At max A/C, the air coming from your vents should be around 40 degrees cooler than the ambient temperature.
 

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