"It can visually look good, but still be bad"
yes my truck had one of these (only part of my prob)
so, now that I have had a chance to look closer, it does actually have a clutch fan, and I noticed the fan was spinning REALLY slow at idle. I think the clutch is bad. Question.. is it possible to just weld up the fan so its no longer a clutch fan? or, how hard is it to replace... I also have another engine in the garage that has a fan without a clutch that I could maybe swap in... but I dont like that fan as much. thoughts?
Should just be 4 bolts to undo the fan. Easy to do. I think you can swap in a non-clutch fan. If you just want to buy one, here is one.
http://denver.craigslist.org/pts/2253604013.html
hahaha, I have been looking at that damn guys post for a year now, reposted every 4 days, wondering when the hell he would just give up.... and now I might need something from him
Does the clutch vs non-clutch make a big difference for any reason? Would one be better than the other for my application? I am tempted to just try the non-clutch I have sitting in the garage. Only reason I dont like it is it has a non-symmetrical fan on it, but was definitely made that way, which is just weird to me. ill take a pic of it tomorrow
decided to go ahead and take pics now. At first it looks like a blade is missing or bent, but it was definitely made this way, not sure why. Not sure if it will be a problem or not.
weird, seems like it wouldn't be very balanced for how fast it spins.
my thoughts exactly. Thats why I am shying away from it until someone tells me there is some logic to it. I mean, its on an identical engine, from one year newer, so I would assume it would work, but you just never know I guess
Steve
Almost all of the rigs that I have had with the exception of a few, have had a fixed blade fan, including a couple that weren't symmetrical like your picture. I have never had any problems with them at all. The design is based on the air flow and I believe that the ones like your pictures are designed that way to flow more air. The main difference in the clutch vs non clutch fan is that the fan offers less drag until your engine reaches a certain temp and also allows the fan to 'freewheel' when it isn't needed. It is also a 'quieter' fan.
The non clutch designs starts spinning as soon as your engine starts, which causes drag, and also causes the engine heater to take more time to warm up as it forces cool air through the radiator as soon as it starts spinning. Also a non clutch fan is spinning all the time, whether your engine needs the cooler air or not. Take for instance driving along the highway when the temp is cool. Your fan may not be needed due to the cooler air being pushed through the radiator. A clutch fan will stop and freewheel, while the non clutch fan will simply continue to pull the air through the radiator. A lot of the clutch style fans are also tied into a thermostat control of some sort so that the clutch 'knows' when to engage or disengage.
I am using a thermostat controlled fan on the Yota as an extra fan for slower crawling. I got rid of the thermostat control and wired it up to a simple on/off switch so I can simply turn it on and off as needed to keep the temps down.
Here is a very good article that explains it a little better than my explanation:
http://www.rowand.net/shop/tech/Ther...icClutchFan.ht
If it were me. I would just mount the non complicated fan (read: one less thing to go wrong, cheaper to replace..) and deal with the slower warm up times. The difference isn't that much.
that explanation makes sense, but also makes me wonder. I think I need to let the engine warm up then and see if the clutch ever engages, if not, it could possibly be the thermostat? Obviously it could still be the clutch too. I probably will just mount the solid fan, because like you said, it is just a lot less to go wrong
My 74 Scout with the 258 had a fixed fan, as do all the Nissan Patrols that I have had. All other vehicles I have had were on a clutch.
The BIGGEST reason to go with a clutch in my opinion is for water crossings. With a clutch the fan can actually stop while the engine is running. When I was in ASE classes, the teacher (smart guy) said you can actually start an engine with a fan clutch and hold the fan still while the engine runs. It is all centrifical force, and it can't overcome someone holding it. On the other hand, don't put your hand in there when it was already spinning. That would be a bad thing. SO, with water crossings, the water can essentially stop a fan. With one with a clutch, no problem. With a fixed fan, it basically becomes a boat propeller and drives forward into the radiator, completely shredding the radiator. Bad idea...
makes sense. I am not horribly worried about it, since that would have to be some pretty darn deep water to hit my fan, but good to know.
oh and steve since my fan is now easy to see since the shroud is out my fan has that same nonsymetrical design to it and its run fine for the last couple months and 3 trailsso it is normal
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