toyota put on a large radiator fan and an thermostatic fan clutch on the tundra that keeps the fan roaring all the time. this is good if you are towing or hauling a load, but most people don't. so you can drill a hole in the fan clutch on the engine side and drain the oil out. the fan will now spin free. thread the hole and put in a bolt to keep a little oil in for lubrication. if you ever need more cooling than the electric fans which you will mount, can give--you can turn the bolt further in. this will lock the fan solid till you don't need the extra cooling, then back the bolt out. move the horns to each side of the radiator. if you are smart you have mounted another transmission oil cooler between the radiator & the a c condensor, and another trans cooler high on the left side in front of the condensor. the little extra trans cooler that was there can be moved and used as a power steering fluid cooler. a 14 inch fan can now be mounted high on the right side over the condensor and a 16 inch mounted low on the left side. each fan is controled by an adjustable thermostat with the temp pick up taped to the upper radiator hose. the right fan is controled by a thermostat(kragen/checker) that turns on the fan when the air coditioner is on and also when it reaches a temperature right before the temp gauge move off it's normal position. you will get over 1 mile per gallon more, more power, and it will be quieter. 40 years as a auto shop teacher and mechanic helped me develope this procedure.
Correct me if I'm wrong, but it was my understanding that a thermostatic fan clutch operates as the name implies, responding to underhood temperatures. When the engine is cold the fan is disconnected, when too much heat is generated the fan is allowed to cool the engine. A bi-metallic thermostatic coil senses the underhood temperature and operates the clutch accordingly.
Originally posted by BillD Think mine will stay just as is, thank you.
Correct me if I'm wrong, but it was my understanding that a thermostatic fan clutch operates as the name implies, responding to underhood temperatures. When the engine is cold the fan is disconnected, when too much heat is generated the fan is allowed to cool the engine. A bi-metallic thermostatic coil senses the underhood temperature and operates the clutch accordingly.
You are indeed correct. The only time it is engaged when its cold is after initial startup from sitting over night. Immediately after shutting down underhood temps go up from lack of air movement thereby heating up the bi-metallic spring to allow max engagement. That's why the fan seems to roar on a cold morning. At this time the spring is cold and set to allow minimal engagement. The fan will quiet down after the revs put enough centrifugal force on the fluid to expel it out of the cavity and disengage it. Then, all is quiet till things heat up. In the summer time, they seem to run full time with the A/C running-as they should. Sometimes on a setup like the Tundra's A/C cooling capacity is diminished when only an electric fan is used as many of these do not provide the volume of air the stock fan gives. Often to gain equivalent volume from an electric you will have to use such a large fan that there will be a high amp load on the alternator giving you back the parasitic drag. Along with reduced alternator life, you get into the law of diminshing returns. Furthermore, a clutch fan is never fully locked. Using a bolt to fully lock the fan will give poor mileage and negate any previous gain. This is a truck so it will have truck like characteristics.
So yeah, mine will stay as is too. Thank you.
Originally posted by Tundra 5150 You are indeed correct. The only time it is engaged when its cold is after initial startup from sitting over night. Immediately after shutting down underhood temps go up from lack of air movement thereby heating up the bi-metallic spring to allow max engagement. That's why the fan seems to roar on a cold morning. At this time the spring is cold and set to allow minimal engagement. The fan will quiet down after the revs put enough centrifugal force on the fluid to expel it out of the cavity and disengage it. Then, all is quiet till things heat up. In the summer time, they seem to run full time with the A/C running-as they should. Sometimes on a setup like the Tundra's A/C cooling capacity is diminished when only an electric fan is used as many of these do not provide the volume of air the stock fan gives. Often to gain equivalent volume from an electric you will have to use such a large fan that there will be a high amp load on the alternator giving you back the parasitic drag. Along with reduced alternator life, you get into the law of diminshing returns. Furthermore, a clutch fan is never fully locked. Using a bolt to fully lock the fan will give poor mileage and negate any previous gain. This is a truck so it will have truck like characteristics.
So yeah, mine will stay as is too. Thank you.
I thought the fan roared first thing in the morning because the silicone oil (thicker when hot, thin when cold) settles to the bottom overnight and needs a few seconds to get redistributed to do it's job...whatever.
Anyway, no thanks. My truck is fine when towing 5000# in 109°F weather and running light in -20°F weather. I do have an additional ATF cooler for those towing days.
My engine roars like a huge mountain beast in heat whenever i've been in fastfood place's drivethrough for a while. Especially when you have to pull out onto an access road at 45mph. It kinda scared me the first few times, but then I realized it was because I had been sitting so long with the A/C on in this good ol' Texas heat.
-Hover
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Ken-I'm with you. Ain't no way I would start messing around with the fan clutch. If it's broken, I would replace it, but I'm certainly not going to mess with something as vital to the health of my engine as the cooling system to gain an insignificant 6hp. The risk is too great.
Originally posted by Hover 011010010010000001101100011011110111011001
100101001000000110110101111001001000000111
010001110101011011100110010001110010011000
0100000000
Okay, I converted it to hex and came up with 69206C6F7665206D792074756E64726100
I'm assuming that it has some significance in octal or decimal?
I was thinking that it might spell something interesting in hex... but what can you spell using only the letters A-F?
tade off that gas/power robbing fan
Too much work
OOOKAYYYYY!
Linear Mode
