Engine fan rubs

[77 K20]

when the truck gets all twisted up when off roading.

Other than switching to electric fans what have others done to stop this? The fan shroud fits just as it should.

 

[chengny]

What part of the fan rubs - and what does it rub against?

 

[77 K20]

As far as I can tell the fan itself rubs against the fan shroud near the bottom. When the truck is sitting flat there is clearance all the way around it.

 

[crazy4offroad]

If it's contacting the top of the shroud it's usually a body lift to blame. I think they make motor mount lifts to alleviate it, or you can trim the shroud (NOT recommended). Otherwise it could be the body mount bushings under the radiator support. If it's the bottom of the shroud it's usually the motor mounts to blame. If your balancer on the crank is less than an inch from the cradle your motor mounts are bad. Depending on how hard you wheel you may want to switch to electric fans. I don't have a body lift but my truck ate pieces of the shroud about every time I went out.

 

[chengny]

It's probably just nicking the shroud. Wouldn't take much of a shift forward to gain sufficient clearance - so as to eliminate the contact.

A washer (or 2) between the water pump flange and the fan hub will move the fan deep enough into the shroud to get clearance - but not so much that you lose air flow.

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[77 K20]

I didn't know about the 1" of clearance from the balancer to the cradle (crossmember). I have maybe 3/8"...

I don't have a body lift but all body mounts and radiator support mounts were replaced a few years ago. This would have just made things even worse.

I'll be looking into motor mounts now. Best just to stay with the OEM rubber type ones or get the harder urethane ones?

If it's contacting the top of the shroud it's usually a body lift to blame. I think they make motor mount lifts to alleviate it, or you can trim the shroud (NOT recommended). Otherwise it could be the body mount bushings under the radiator support. If it's the bottom of the shroud it's usually the motor mounts to blame. If your balancer on the crank is less than an inch from the cradle your motor mounts are bad. Depending on how hard you wheel you may want to switch to electric fans. I don't have a body lift but my truck ate pieces of the shroud about every time I went out.

 

[crazy4offroad]

I would verify the mounts are bad before you change them, since they are a real bitch to change. Stick a prybar between the frame and engine and give it a lift and see if the mount is torn. If not Jerry's (chengny) suggestion would be much easier. But honestly these trucks flex like crazy, neither fix might not help depending how hard you wheel, which is why I eventually found my way to electric fans.

 

[77 K20]

I power braked it with the hood open and watched the engine start climbing. Also when out at the ORV park I noticed how much the transfer case lever would dance around when in 4 low. Figure the engine mounts and the transfer case mounts haven't been changed by me I might as well to know they are done. Picking them up at NAPA tomorrow. Whole setup is around $50 for OEM type ones.
Maybe it will make things better. If not no big deal.

 

[bucket]

It should take care of it, but who knows how long. The cheap parts store replacements don't always last very long at all.

 

[77 K20]

Not sure why I posted this in the lifted suspension forum... should have been in the off roading section.

But the NAPA motor mounts and transfer case mounts were installed (they do have a 12,000 mile warranty). New mounts lifted up the engine a little over 1/2". I have more room now for the fan. Haven't got a chance to twist up the truck but it should be much better than before. The steering box brace I just added might help a bit.

This also helped my transfer case lever not dance and rattle around as much.

 

[bucket]

Not sure why I posted this in the lifted suspension forum... should have been in the off roading section.

Done.

I'll be interested to see how your mounts hold up. Not that they will fail, just out of curiosity really.