I have 97 LX450 with 292K. I believe I have an original Fan Clutch. My mechanic told me that I need to replace it because because when I am at the stop sign or waiting for the light to change my AC is not cooling enough. It doesn't make any noises, truck never overheats. Question, is my mechanic correct or it's just not enough freon n the system. I replaced compressor and dryer last April. I bought Denso AC compressor. Thank you!
OEM Fan Clutch or Aisin Fan Clutch will be fine (1 Viewer)
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Warm AC at idle is usually fan clutch related.
If the AC is cold when you are moving then warms when you are stopped a weak fan clutch seems the most likely culprit to me.
The good thing is that if the fan clutch is in decent shape and of good quality it can most likely be serviced and restored to as good as new (or better) functionality. Tuning the opening temp and changing the oil of a fan clutch should fix any new or old fan clutch that is too week but otherwise in good shape. It's worth noting that I have experienced an under performing Aisin blue hub fan clutch that was new and quickly allowed the engine to exceed 220.
If the fan clutch is not pushing enough air at idle then insufficient air will be flowing through the condenser. The condenser is the "radiator" that you can see the fins of when you look through an 80s grill and is what cools the AC refrigerant after it has been re-compressed.
A few things to check when you suspect an under performing condenser:
One test that can help you narrow in on condenser performance being the limiting factor in the AC system is spraying water on the condenser/grill when the 80 is at idle. The water will increase the cooling that the condenser does and if the AC temp in the 80 drops quickly after then you can focus on getting good airflow though a clean condenser to improve AC performance.
While you are figuring this out I would start keeping an eye on engine temps because the fan and fan clutch are a key part of cooling both the AC and the engine. AC is nice but not overheating the engine is essential... The stock gauge in the cluster is insufficient and you'll need an odb2 or hardwired setup to monitor actual coolant temps. There's a lot of good discussion on engine temps and temp monitoring setups on the forum.
A few additional ideas on the AC side of this:
Good luck sorting it out.
The good thing is that if the fan clutch is in decent shape and of good quality it can most likely be serviced and restored to as good as new (or better) functionality. Tuning the opening temp and changing the oil of a fan clutch should fix any new or old fan clutch that is too week but otherwise in good shape. It's worth noting that I have experienced an under performing Aisin blue hub fan clutch that was new and quickly allowed the engine to exceed 220.
If the fan clutch is not pushing enough air at idle then insufficient air will be flowing through the condenser. The condenser is the "radiator" that you can see the fins of when you look through an 80s grill and is what cools the AC refrigerant after it has been re-compressed.
A few things to check when you suspect an under performing condenser:
- is the fan clutch engaging enough to pull good air at idle?
- is the fan shroud in place?
- is the foam between the radiator and the core support intact?
- is the condenser clean with mostly open ports?
One test that can help you narrow in on condenser performance being the limiting factor in the AC system is spraying water on the condenser/grill when the 80 is at idle. The water will increase the cooling that the condenser does and if the AC temp in the 80 drops quickly after then you can focus on getting good airflow though a clean condenser to improve AC performance.
While you are figuring this out I would start keeping an eye on engine temps because the fan and fan clutch are a key part of cooling both the AC and the engine. AC is nice but not overheating the engine is essential... The stock gauge in the cluster is insufficient and you'll need an odb2 or hardwired setup to monitor actual coolant temps. There's a lot of good discussion on engine temps and temp monitoring setups on the forum.
A few additional ideas on the AC side of this:
- The AC system will shut off whenever the engine's coolant temp rises to around 220 degrees, roughly. Knowing the engine temps will allow you to track their coincidence with AC shutoff and, if that is happening, avoid going any hotter.
- The AC system will shut off if the pressure of the refrigerant gets too high. This is often caused by the AC system being overcharged with too much refrigerant. If their is too much refrigerant in the system the AC can run well when in normal temps but become over pressurized and shut off when hot and the refrigerant has expanded enough. Auto AC is easy to overcharge if refilling from a spray can like the ones you can pick up at an auto parts store.
Good luck sorting it out.
- Thread starter
- #4
Where can I find fan clutch rebuild kit including oil? By the way, my temperature gauge indicator is always below the middle mark.
If you take apart a clutch and see all that grey material I’d replace the whole clutch.
I think that folks are often in the 15k cst to 30k cst range with the oil they use these days. The Toyota oil is typically a lower CST but may be a higher quality. Here's a hobby version of the oil that should cover the refill on a blue hub:
You'll hear from some that changing the oil is all that you need to do but that's not always true in my experience. Sometimes the plates open up at too high of a temp to support sufficient cooling and I'm sure that some may open up too soon and waste fuel mileage. I prefer to use a double boiler and candy thermometer method to calibrate the opening temp on these but you can try a heat gun, etc. The last time I setup a blue hub I set it to: small hole 50% open at 110 degrees and have been pretty happy with that setting.
The only part you need for a rebuild is the oil, the rest of the needed supplies are the tools to remove the fan clutch, split it in half and adjust the opening temp.
You'll hear from some that changing the oil is all that you need to do but that's not always true in my experience. Sometimes the plates open up at too high of a temp to support sufficient cooling and I'm sure that some may open up too soon and waste fuel mileage. I prefer to use a double boiler and candy thermometer method to calibrate the opening temp on these but you can try a heat gun, etc. The last time I setup a blue hub I set it to: small hole 50% open at 110 degrees and have been pretty happy with that setting.
The only part you need for a rebuild is the oil, the rest of the needed supplies are the tools to remove the fan clutch, split it in half and adjust the opening temp.
- Thread starter
- #8
Where can I find an O-ring, from a dealer or just use RTV Gasket maker instead?
I'd reuse the oring that is part of the fan clutch already, as long as it's in good shape. Given the importance of the fan clutch and it's relatively low cost I'd just replace the whole fan clutch if it has a bad o ring from normal use (and not from mishandling when apart or improper assembly on your part). This may be overkill but I'd rather just start with a new Aisin blue hub than worry with putting an oring in an old clutch that could have other issues. The o ring shouldn't typically get damaged or wear out under normal conditions so reuse should be fine. I've heard of the oring being a little large and one person reported cooling/freezing the oring to shrink it for reinstall in a thread I read, etc.
All that said you may be able to find a source for a replacement o ring by searching the forum. Drop something like this into Google:
All that said you may be able to find a source for a replacement o ring by searching the forum. Drop something like this into Google:
fan clutch o ring replacement site:forum.ih8mud.com
- Thread starter
- #10
Yep, that's the Aisin blue hub everyone talks about on the forum.
I purchased a new one that allowed my 80 to hit 220 after I'd climb the hill to my house and then let the 80 idle. It seemed underfilled with oil when I drained it and was opening up at too high a temp. Many folks have good luck running blue hubs out of the box and it's worth a try if you can monitor temps after the change but I like to mention that they can have issues when new. I'd order new oil at the same time and do the tuning/oil change before install personally because it's really easy / cheap to do.
I purchased a new one that allowed my 80 to hit 220 after I'd climb the hill to my house and then let the 80 idle. It seemed underfilled with oil when I drained it and was opening up at too high a temp. Many folks have good luck running blue hubs out of the box and it's worth a try if you can monitor temps after the change but I like to mention that they can have issues when new. I'd order new oil at the same time and do the tuning/oil change before install personally because it's really easy / cheap to do.
I bought that blue hub and mine is inadequate for cooling. I'm pretty sure it's exactly as @jpoole stated. I have two bottle of CST 15K in my possession now, just gotta find time to do it. If I would have realized this to begin with, I would have opened it up immediately and changed the fluid to be sure. I'm in the Midwest and don't typically see the heat extremes of the other folks, but mine can no longer hold the cooling if I'm pushing it at all.
- Thread starter
- #13
How many fluid ounces do I need, 2 or 4?
- Thread starter
- #14
20K, is better, right?
Well, I bought (2) 2 oz bottles. Now I'm questioning if that's enough.
If you're in a hot environment, you can go higher CST (20K) but at the risk of your fan being engaged 100% of the time, lowering your mileage. Check with other folks in your area.
Read through this thread for the best info.
Blue fan clutch mod...Thread has gone to hell, read at your own risk
History: On my first drive this summer after replacing my transmission I was having an overheat condition with the truck. On the following weekend while towing a camper it was real severe in the 230* range. After returning I was able to confirm that my Blue hubbed fan clutch was to blame...
forum.ih8mud.com
- Thread starter
- #16
Well, I bought (2) 2 oz bottles. Now I'm questioning if that's enough.
If you're in a hot environment, you can go higher CST (20K) but at the risk of your fan being engaged 100% of the time, lowering your mileage. Check with other folks in your area.
Read through this thread for the best info.
Blue fan clutch mod...Thread has gone to hell, read at your own risk
History: On my first drive this summer after replacing my transmission I was having an overheat condition with the truck. On the following weekend while towing a camper it was real severe in the 230* range. After returning I was able to confirm that my Blue hubbed fan clutch was to blame...
I ordered AISIN FCT-004 Engine Cooling Fan Clutch from Amazon. Should be getting it on 7/26 I will post the results after replacing my old one (27 years old) ...Well, I bought (2) 2 oz bottles. Now I'm questioning if that's enough.
If you're in a hot environment, you can go higher CST (20K) but at the risk of your fan being engaged 100% of the time, lowering your mileage. Check with other folks in your area.
Read through this thread for the best info.
Blue fan clutch mod...Thread has gone to hell, read at your own risk
History: On my first drive this summer after replacing my transmission I was having an overheat condition with the truck. On the following weekend while towing a camper it was real severe in the 230* range. After returning I was able to confirm that my Blue hubbed fan clutch was to blame...
This may need to be clarified a bit so that oil weight isn't given too much credit in terms of how fan clutches work.
- The temperature at which the ports open controls when the fan clutch starts to engage. As the fan clutch gets hotter the ports open more and allow more fluid out into the shearing area.
- The weight of the oil controls how effective the shearing action is. A thinner oil equals less drive from the fan while a heavier oil leads to more fan drive and more air moved.
Extreme conditions, like rock crawling in the Desert in Summer, likely benefit from heavier oil that gets as much fan drive as possible. For most conditions 7k to 10k is likely plenty though 15k to 20k doesn't seem to cause noticeable over engagement.
The more likely way to kill your fuel mileage would be to set the fan clutch ports to open at too cool a temp. If the fan clutch engages too soon then you could end up driving around with an engaged fan and a closed thermostat which would definitely mean you are just wasting energy at that point. You want the engine to get to operating temps with a fully open tstat before fully engaging the fan clutch... With that in mind you likely want to test to see the opening temps for the small and large ports before you make adjustments on the fan clutch.
The small port opens first and I assume is primarily to keep a little air moving so that if the radiator is hot the fan clutch will "find out" and be able to open more. Without a little air motion the rad could get hot and the fan clutch not heat up enough to start the air flow cycle, when parked for instance.
The larger ports are the "drive" ports that lead to the fan moving a lot of air and you'll want them to fully engage at a reasonable temp.
Setting the opening temps is complicated by the fact that air is being used to connect rad temps to fan clutch temps, etc. so trial and error may be required or you can just follow what others have shared and used with success here on the forum. I seem to recall that the small port half open at 95 degrees is a common setting. I set the small port to half open at 110 on my blue hub that is running 15k cst with the idea of allowing the fan to come in later and have had good results with it keeping the top end temps under control.
I also purchased the Aisin FNT-004 cooling fan to go with it because of OCD........ Plastics do fail and mine was original with about 320K miles on it.....
- Thread starter
- #19
Installed AISIN FCT-004 Engine Cooling Fan Clutch and it's working great. Solved my A/C issues.
bj70alex did you change any clutch fluids before using your new clutch fan, or just bolt it on and go? Also, do you have any before/after temps?
