Sierra Fan Upgrade

[gwagensteve]

I've been pretty unhappy with the stock mechanical fan on my 660 for some time, and decided to do something about it.

I sourced a Vitara viscous fan from pick-a-part, and modified it fit my 660. All common sierra/vitara motors have the same fan bolt pattern AFAIK and also seem to share the same spigot size.

However, models with viscous fans have long water pumps with studs fitted to them, whereas models with fixed fans have spacers and bolts. This presented a problem for me as I couldn't install the bolts and spacer as the hub of the viscous fan was in the way. I noted that alignment of the fan is done by the spigot, and that the bolts only provide tension to keep the whole thing assembled, so I figured I could slot the bolt holes in the fan hub for assembly with no ill effects.

Here's some pics.



Here's a 4 blade 1.0 fan, a vitara fan, and a 5 blade fan ( in this case from a factory 660, but I think it's the same as a 1.3 fan)



Here's the 660 fan over the Vit fan. Should pull a bit more air methinks.



Here's the install. I used a 1.3 shroud, not the much deeper 660 shroud. Also, the fan wouldn't clear the bottom of the 1.3 shroud due to the diameter. I cut the bottom of the shroud out and added a strip of shroud from a vitara. It's attached with 6mm screws and nylock nuts.

I haven't had it on the road yet, but it's doing all the normal viscous fan stuff, like freewheeling under revs on a cool motor etc. Clearance between the fan and shroud is pretty tight - maybe 5-10mm, and it remains to be seen if I will have to enlarge the shroud more to allow for engine movement under load, but the engine seems to sit pretty still so I might be OK.

I think with this setup, I should both gain HP and have better cooling when required - along with a huge reduction in cabin noise.

I'm pretty happy. This mod should work on 1.3 Sierras too with the shorter fan spacer of the 1.3 instead of the loooong spacer of the 660.

Steve.

[cj!]

Hmmmm.....asymmetric fan. I must have a look at the one I grabbed, I didn't notice it looking like that.

[gwagensteve]

I think that's part of what keeps the noise down.

Can't say I've noticed if a 1.3 5 blade fan is assymetric or not.

Steve.

[gwagensteve]

FAIL

This didn't work.

The first time I tried it on the road I ended up with a big water leak - water pump seal. I did the research and replaced the seal, and replaced the seal, and replaced the seal, and then resealed the housing, and it all seemed good, so I put the vitara fan back on... and almost immediately blew out the pump seal again.... on a run to the tip, with no water with me...

I bought some coolant and water 1/2 way back to home, and by the time I was 1km from home, water was pouring out so fast I literally couldn't pour it in the radiator fast enough.

Now, I'll say that the reason it didn't work was because of the peculiar setup of my 660 - the water pump bearings are in line with the timing belt so the fan needs to be on a long spacer to get away from the pulleys and close to the radiator. This amplifies the effect of the weight, play and size of the viscous fan, and sets up resonance that destroys seals.

I'd say a stock 1.3 sierra would be fine with this upgrade and there really is an enormous drop in cabin noise with this fan installed.

anyone want one...

Steve.