Fan Keeps Hitting Radiator... Head Scratcher

Apologies for posting so many help me threads this week, it's hurry up and fix the jeep season for me. I've had a strange recurring issue since last year that i just can't get to the bottom of. Last year I ran over a stick that went up into the engine compartment and collided with the fan, which bent forward and sliced my radiator open. I got the radiator repaired and bent the fan back into place and ran the jeep hard all winter and then a little more this summer.
Then, totally at random a few weeks ago just riding down the gravel road, the fan somehow connected with the radiator once again and sliced it open.
After the second incident I bought a new champion aluminum radiator that bolted right in, as well as a new 15.5" universal fan, and with everything installed there is about 1/8" clearance between the bottom of the fan and the radiator. I'm too scared to crank it up like that.

What I'm noticing:

There is a bit of play in the output shaft of the water pump that allows the fan to wobble ever so slightly.

The engine is not level to the engine bay. Is that normal? It leans back maybe 5 degrees which puts the bottom of the fan very close to the radiator and the top of the fan a few inches away.

Motor mounts seem good. They were replaced a few years ago. When I push on the engine it doesn't have any play or anything. Not sure how else to inspect.

Thoughts:

I really don't know why I am having this problem suddenly but it must be related to that first incident. Something seems to have shifted or else I just never noticed how close they were.. but what could have moved?

I'd rather avoid putting in an electric fan even though that would "solve" the issue from a certain point of view.

Not sure what other options I have other than go with an electric fan.. they are kind of expensive and I'm afraid it'll be loud also. Among other possible drawbacks.

Has anyone had this kind of issue?

 

Make sure the grill is bolted down solid at the bottom and on the fenders. You might be able to loosen up the bolts and pull the grill forward on the fenders a bit then tighten them back down.
The engine angle is normal, carburetor base should be wedged to compensate.

Water pump should not wobble or play.

On 4cyls they have a stay cable on the motor.
See if you can find a round BBQ grate to protect the inside of the radiator and maybe use some wood shims on the fender to body until you can gain clearance elsewhere.

 

Hey Henri, sounds like you’re getting close to getting this figured out. A few things come to mind:
- I put in a Champion Radiator a few years ago to help solve a running hot issue. Its the larger of the two they offer for the V6 CJs (69-71). Mine has a larger volume than the factory radiator…it was a direct bolt-in but it’s thicker, thus I lost some fan clearance.
- Seems obvious, but are you running a fan spacer?
- I agree that 1/8” is way too close. I like at around 1.5-1.75” from the radiator because I’m paranoid. What is your fan? A flex fan will expand some. This is particularly risky going through water if you have marginal clearance.
- I also agree that play in the water pump shaft is not good. New water pump time.
- You may have an issue with clearance for an electric fan as well if it’s that tight in there. In that case you may be looking at a pusher on the front. I run both a mechanical fan with shroud and an electric pusher that I only run in high demand (hard 4-wheeling) situations.

Edit: I just measured. I have about 1.75" clearance from the fan blades near the center of the radiator and about 1 1/4" at the bottom.

If you're curious here is the E-fan I use: Like you mentioned, its loud. But it does move some air. PERMA COOL 14"

 

Body shifted? Check the body mounts? Stay cable?

Is it possible the press-fit waterpump shaft has slipped forward from the impeller???

 

I see in your signature . it's a V6 4speed
how many spacers do you have on cross member

 

I'm also assuming you don't have any spacers or just enough so the fan clears the crank pulley. Both of my V6 Jeeps (one with the wider radiator and one with the narrower radiator) have 1/2" - 3/4" clearance between the fan and the lower tank of the radiator with stock fans and 1/2" fan spacers.

Is it a factory V6 Jeep? Is it possible the V6 was swapped in and isn't in the factory location?

Another possibility is you have a 231 or someone installed a 231 water pump. The 231 water pumps are quite a bit longer. My '69 had one on it's 231 that just cleared the stock radiator but I needed to switch to a 225 water pump to clear the Champion radiator.

231 Pump on the left, 225 pump on the right:


Of course you need to get the matching pulley to go with the pump. 231 pulley on the left, 225 pulley on the right:

 

Interesting the diameter changed that much. The 231 pulley looks to run the fan 15-20% faster.

I'm another that likes 1/2-3/4" minimum clearance between the fan and any part of the radiator. Is the new fan rigid or flex bade? If the latter, you may want to observe those blades as you increase the rpm to see if they are getting sucked forward a bit.

 

You mean between the crossmember and the transmission mount? I'll have to check

 

It is a rigid fan, as was the original. The slight wobble in the water pump shaft is a factor for sure. Without that, I'd have at least a quarter inch or more, which still isn't much, but better. If there's a cheap electric fan I can bolt in for a few months and then dive into all this later I would do that. Not sure what fans would fit this champion radiator.

 

Replace motor mounts.

 

Got the new radiator installed, went with a generic 16" electric fan with Chinese instructions that didn't match the product, and after some fussing and rewiring I got it rigged up and working. The clearance is still TIGHT. Quarter inch max.. but at least it might not tear everything to bits if they bump again now that the pulley fan is gone.

I know I could have put the electric fan on the outside of the radiator and wired it to blow inwards, but I wanted to keep the noise down as much as possible by putting it under the hood. If that becomes an issue in the future I'll swap it to the outside in order to open up some clearance

 

Meanwhile I may have gotten closer to the root cause of the lack of clearance. When I had a local shop install my t98 they hacked the crossmember support pretty bad. Looks like it is bending downwards which would increase the angle of the motor causing the bottom of the fan to move closer to the radiator.

 

So for this transmission support that had to be fabbed to fit the T98 adapter plate, if I were to redo it, would I need to custom fab something again? Or is there a support out there that will pair up to the adapter plate? Looks like the issue is that they are offset by 2 inches or so.

 

ditch that makeshift adapter
move the cross member to line up with transmission

 

Good call. I've got a new support in the mail and that would definitely be an easier solution. Can't access my transfer case plug the way things sit anyways.