Cooling fan for L20B

[650savag]

My clutch type cooling fan is locked up and sounds like a jet plane when I rev the engine. I'm thinking about going with a standard 4 blade fan or 12V fan if I can find one that will fit. Anybody happen to have one lying around that they would part with?

[datzenmike]

You'll have to replace the pump as well.

[wildmaninid]

Yeah, you will need a new pump off of an earlier pickup, like a 77. I have an absolutely gorgeous factory fan blade. Looks nearly brand new the plastic is still white and nice.

[datzenmike]

I think all L20Bs had the clutch fan. Try earlier L16/18s

[650savag]

Thanks, Mike and "Wildman" for your help. I was afraid that was going to be the case. I was hoping I could just find a 4 blade fan and change it out but I guess I will have to put up with the sound or change out the pump and all. Since the engine has approximately 130K and the pump is original then I'm wondering if the fan might stop working altogether soon? I mostly drive it to work which is a 30 mile comute on lightly traveled highway and I am not in stop-and-go traffic much at all. Still, I woluld hate to take the chance on the fan not working and overheating my truck engine. I also considered trying to remove the fan from the pump and mount a 12V fan between the radiator and pump and have a switch inside that I could turn on if I needed it. Of course, if someone else drove the truck then they might not understand when to turn it on. "Wildman", are you saying that you have a complete assymbly (pump and clutch/fan) for sale?

[screamer510]

I have one. Pump, fan, clutch. Good condition. In GA.

[banzai510(hainz)]

L20s that I seen had 2 style fan clutch fan assembeles. for cars and the trucks. the hole spaceing(hubs) were different

 

click on Rockauto and look at the photos and maybe you can see a difference.

I stick with the 510 set up non clutch type and is pretty much universal.

 

But the later l20 fans are bigger and multibladed

[650savag]

I checked RockAuto and they sell two different types (AC and Non-AC). The non AC has a 4" bolt pattern and the AC has a 5 1/4" bolt pattern. Mine origianally had AC, although I removed all the components, I probabaly have the water pump with the large bolt pattern. I may just get a new water pump ;for non AC and then I can just get a plain 4 blade fan with 4" bolt pattern. Thanks for all the info!

[650savag]

I did some more measuring on mine. It is the larger bolt pattern and the fan has 8 blades. Screamer510 has an assembly that came off of a 1977 200sx that is in good shape and I am wondering if this will be a direct bolt on for my 620. Also, I have read that if the fan is locked up, like mine is, then it might cause less air to flow at highway speeds. Does this make any sense? Would it be alright just to drive it like it is and put up with the "school bus" sound? It really don't bother me but I don't want to take a chance on getting stranded on the road with an overheated engine. May Mike or Hainze or some of you other guys would comment. Thanks, Dan

[Z chopper]

the fan does help pull air through the rad to help with engine cooling, so if the fan ain't working right then overheating isn't too far away

[ggzilla]

If the fan clutch is locked up, the fan keeps turning. So you are in no danger of overheating from a locked fan clutch.

 

The purpose of the clutch is to stop spinning at certain time to save fuel economy and lessen noise. No worries, it won't overheat.

[650savag]

Thanks ZChopper and ggzilla for the help. I think I am going to park it and drive the 720 until I get this issue resolved. The water pump is still working and it hasn't overheated yet on my comute to work and back but I noticed yesterday that the belt was starting to squeal occasionally. I have a hunch that the pump may be starting to try to sieze up. I haven't noticed any leak from the pump and I know that usually when the pump goes out that you will notice some leakage from the seals. Do you think that the pump and clutch/fan assy. that Screamer has will fit on my 620? He says he thinks it came off of a 1977 200sx, L20B. If it will work, I probably will get the used one from him or just order a new one from RockAuto. I will need to get a belt and gasket anyway. Maybe you guys could give me some advice on that. Thanks, Dan

[Z-train]

Fixed bladed fans are really not a good idea.

[banzai510(hainz)]

Loosen the belt. see if the pump spins and isnt loose in the bearing dept.

Persoanlly if its not leaking fluid I would just run it. If clutched is locked up its just like a fixed fan then pulling all the time. You just have more rotational mass to move around.

Buy a spare when ever.

But this is just me

[650savag]

Loosen the belt. see if the pump spins and isnt loose in the bearing dept.

Persoanlly if its not leaking fluid I would just run it. If clutched is locked up its just like a fixed fan then pulling all the time. You just have more rotational mass to move around.

Buy a spare when ever.

But this is just me

Thanks hainz. That was kinda what I was thinking untill the belt started squealing occasionally. I may try to snug the belt up a little and see if that stops the squealing. Do you think that the pump assy. that Screamer has will fit my truck? It's a pump and clutch and fan and he thinks it came off of a 1977 200sx, L20B.

[68Datsun510]

So what is the difference between a ac and non ac pump/clutch besides physical appearance? Does one clutch in better? Firmer? My fixed blade isn't cutting it...