'97 Fan Clutch

[97 FZJ80]

I just hooked up the OEM aux fan with the late blue hub Aisin clutch on its original fluid. We had 104F temp today and the AC is acutually stayed cold, not frozen cold but cold enough and stays cold in low speed around town even after the heat soak.

I'll put in the 30k fluid and see how much it improves.

 

[psfpilot]

I just hooked up the OEM aux fan with the late blue hub Aisin clutch on its original fluid. We had 104F temp today and the AC is acutually stayed cold, not frozen cold but cold enough and stays cold in low speed around town even after the heat soak.

I'll put in the 30k fluid and see how much it improves.

If the clutch thermostat isn't currently set to engage at a low enough temperature, higher viscosity fluid won't make much difference. When I pulled my fan clutch for a second time after adding the 30k fluid without a difference, and finally set the clutch using LT's blue hub method from the FAQ, it began to pull air well and the AC started working better.

 

[97 FZJ80]

Clutch adjusted and 30k fluid put in. Vent temperature went from 67F (OEM aux fan and stock Aisin replacement clutch) to 62F (OEM aux fan and stock cluck with valve adjusted and 30k fluid). Air temperature about 100F and the heat soak on the pavement was 123F.

 

[cary]

I think you are trying to fix a shortcoming in your A/C that is not cooling related. Your temps should be below 60F and preferably in the 50f range. I thinks there is something up with your A/C.

 

[Tools R Us]

If the clutch thermostat isn't currently set to engage at a low enough temperature, higher viscosity fluid won't make much difference. When I pulled my fan clutch for a second time after adding the 30k fluid without a difference, and finally set the clutch using LT's blue hub method from the FAQ, it began to pull air well and the AC started working better.

Agree, if it is out of spec, but I have never seen one out of spec. All that I have tested have been very consistent, at what temp was yours fully open before you set it?

If you monitor fan output temp, you will see that it's in the 170-190F range when idling/stop & go traffic on hot days. For example the Eaton I did yesterday started opening at 120F and fully open at ~160F. So at low motor/rig speeds it's going to be fully open.

If I had set it to 95/135F it would still be fully open at low motor/rig speeds, no advantage, fully open = fully open. But also would be fully open at highway cruise speed ~130-140F wasting energy where it's not needed.

I have set them all over and have never seen an measurable advantage to setting them too cool. When thicker fluid is used, each valve opening is stronger than stock. Mine is set the other way (IIRC ~125-175F) and works great.

 

[abrumley]

I'm fighting the same problem right now. I am gettin vent temps in the 62/63 area. Ive already replaced the entire a/c system. Modded the clutch change the t-stat. flushed and cleaned radiator. The truck is running in the 190 area but i just cant figure out why the a/c is blowing colder

 

[Tools R Us]

Clutch adjusted and 30k fluid put in. Vent temperature went from 67F (OEM aux fan and stock Aisin replacement clutch) to 62F (OEM aux fan and stock cluck with valve adjusted and 30k fluid). Air temperature about 100F and the heat soak on the pavement was 123F.

I think you are trying to fix a shortcoming in your A/C that is not cooling related. Your temps should be below 60F and preferably in the 50f range. I thinks there is something up with your A/C.

A/C vent temp is pretty much worthless unless all of the parameters (A/C fan, recirculate/fresh, windows open/closed, ambient temp, sun/shade, etc) are known. I can take any rig with a half way descent working system, pull it into the shop with the cooler blowing on it and make it blow 40F or less. This is worthless to judging how it will preform in the real world.

A/C output is usually described by a temp drop difference from ambient, but is very dependent on conditions. Here even sun or shade makes a big difference in vent temp.

 

[psfpilot]

Agree, if it is out of spec, but I have never seen one out of spec. All that I have tested have been very consistent, at what temp was yours fully open before you set it?

If you monitor fan output temp, you will see that it's in the 170-190F range when idling/stop & go traffic on hot days. For example the Eaton I did yesterday started opening at 120F and fully open at ~160F. So at low motor/rig speeds it's going to be fully open.

If I had set it to 95/135F it would still be fully open at low motor/rig speeds, no advantage, fully open = fully open. But also would be fully open at highway cruise speed ~130-140F wasting energy where it's not needed.

I have set them all over and have never seen an measurable advantage to setting them too cool. When thicker fluid is used, each valve opening is stronger than stock. Mine is set the other way (IIRC ~125-175F) and works great.

I did not measure the fully open/fully closed temps so I don't have an answer for that question. To which holes are you referring, the small round hole (arrow below) or the large parallelogram closer to the hub centerline (above it)? I set it for small holes half open at ~95˚F; IIRC it was previously half open ~110˚F in the water bath (and pulling only a modest amount of air).

 

[97 FZJ80]

I know that AC output temperature is a function of multiple factors, which ambient temperature, heat soak, humidity, and other environmental factors. The two temperature readings were done around noon on two days with similar temperature, humidity and heat soak. The only thing was that the hood was up and the windows open (not correct, I know) and the temperature setting on the AC was at the regular 74F.

The AC performance was really improved when i drove the truck around in the 104F in the afternoon. I ran a few errands and had lots of stop and gon traffic, including a couple of tests where I parked for 30 to 60 minutes in the sun. Everytime after the heat soak from parking for 30+ minutes, the AC turned on to cold temperature within a couple of minutes, and really cold temperature within 5 minutes. The auto AC in the AC used to stay on high (fan setting #4) the entire time I'm driving in the afternoon. Now, the auto AC kicks down to Med-High (fan setting #3) after 5 minutes. This is about the same AC performance I get from my Tundra, which has a very efficient AC system cooling a cabin that is less than 1/2 the volume of the 80 cabin.

I have never heard the engine fan roar in the entire 12 years that I owned this vehicle. The original Aisin clutch was replaced with a new blue hub aisin clutch a couple of years back, and the a AC was alway marginal at best this entire time. After this 30k fluid and clutch valve adjustment, the fan clutch now engages with a loud roar when the engine is above 2.5k RPM. I am a little concerned that the engine fan still roars when the engine is above 2.5k RPM at highway speed. But then again, the ambient temperature was 104 today. Since my AC has never cool properly before this mod, even at highway speed, so my concern might not amount to anything. I will monitor this closer to see if it affects my gas milage.

On a different front, the OEM aux electric fan pushes a lot of air and based on our informal cigarette smoke test, the OEM aux fan pushes more air than the stock fan at idle. My aux fan is wired to run based on the AC pressure setting, regardless of ignition switch and AC switch settings. The fan will continue to run after the engine has shut down. After a particularly long drive in the heat, the fan ran for over 10 minutes after I shut the engine off. I might need to finish my aux battery system and run the aux fan on the second battery so that I do not accidentally drain down my main battery.

Overall I am very happy with the performance of the 30k fluid and the clutch opening adjustement. I will monitor this closely this week as we have 100F+ every day this week. I'll report back with updates if there are any changes.

 

[Tools R Us]

I did not measure the fully open/fully closed temps so I don't have an answer for that question. To which holes are you referring, the small round hole (arrow below) or the large parallelogram closer to the hub centerline (above it)? I set it for small holes half open at ~95˚F; IIRC it was previously half open ~110˚F in the water bath (and pulling only a modest amount of air).

I use first opening and fully open, but don't use water bath anymore. Found warm air (heat gun, hair dryer) and measuring the actual spring temp to be quicker, more accurate/repeatable.

 

[Tools R Us]

I know that AC output temperature is a function of multiple factors, which ambient temperature, heat soak, humidity, and other environmental factors. ...

Sorry, my post wasn't more clear. My point wasn't your observations, it was Cary commenting that it should be cooler, IMHO there wasn't enough info given to make that determination?

... After this 30k fluid and clutch valve adjustment, the fan clutch now engages with a loud roar when the engine is above 2.5k RPM. I am a little concerned that the engine fan still roars when the engine is above 2.5k RPM at highway speed. ...

When we first started using thicker fluids, had the same experience at highway speeds, also when downshifting, sometimes would slip/scream the belt. Played with valve setting and found that about where the factory set it or slightly warmer worked best. Allowed for good drive at low speed heat soak and no issues at highway speeds.

 

[psfpilot]

I use first opening and fully open, but don't use water bath anymore. Found warm air (heat gun, hair dryer) and measuring the actual spring temp to be quicker, more accurate/repeatable.

Witch hole?

 

[97 FZJ80]

Wow! The auto AC kick the fan down to 2 for the fan setting (med low) at highway speed. This is with an afternoon of heat soak and 104F ambient air temperature. It has NEVER don that even when the car was new...

I like the AC clutch mod. But I do attribute part of the lower AC temperature at idle/stopped to the aux OEM AC fan. It moves a lot of air. Based on our un-scientific research, it moves as much air as the engine fan at idle.

 

[lndcruz]

Still seems that your temps are pretty warm. My 80 with 10k runs about 193-195 with the air temp of 98 1000% humidity.

 

[Tools R Us]

Witch hole?

The first hole to open, most times the small one in the shearing ridges.

 

[jlg32281]

I thought I read somewhere that Landtank modifies fan clutches and sells them, anybody know if he does this and the price? What does a new fan clutch cost?

 

[RescueU]

Fellas, Not to hijack the thread, but how are you all taking the various temp readings. They seem precise enough in measurement and system/component-specific descriptions that make me think it's via the OBD-II port. If it is the OBD port, what software are you using? I'm just trying to dial in my tools and testing environment when comparing my results with the posts. Thanks!

 

[94SRUNNER]

RescueU.....I am fairly sure that all of these temp readings are coming from the ScanGauge II OBD-II reader or something similar. At least that is where mine are coming from. They are discussed in length on this forum. As an owner of a 97' your 80 is capable of supporting one and they make a great diagnostic tool.

 

[Tools R Us]

Fellas, Not to hijack the thread, but how are you all taking the various temp readings. They seem precise enough in measurement and system/component-specific descriptions that make me think it's via the OBD-II port. If it is the OBD port, what software are you using? I'm just trying to dial in my tools and testing environment when comparing my results with the posts. Thanks!

OBD2 is good for a couple of measurements, I also use digital thermometers, thermocouples for air temp. Usually several at a time, one for grill input and some under the hood to compare temp gain in areas of interest.

 

[ncduckman]

I thought I read somewhere that Landtank modifies fan clutches and sells them, anybody know if he does this and the price? What does a new fan clutch cost?

I believe he sells them for around $200. He will mod an existing one for around $60. A new blue hub clutch from Toyota lists at around $170, but they can be had cheaper (Cdan). Don't quote me verbatim on these numbers, as I am going off the top of my head. Landtank has a thread somewhere (vendor's section?) with his prices.

Hope that helps.
Robert