Fan Hitting Radiator when accelerating

[Kappy415]

I know this topic has been discussed before, but this time it's DIFFERENT (sort of).

I recently installed a new radiator, aftermarket, after determining it was the source of my cooling woes. The clearance is less than it was with the original but still 3/4"

Took several 75-100 mile trips and noticed the fan was hitting the shroud, but only when I accelerated quickly (either from a stop or in the middle of traffic).

Drained and removed the radiator and I noticed the fan had been hitting the radiator fins, not the shroud. No real damage caused but obviously the problem still needed to be fixed.

Based on the various forum posts on the issue, I figured new body mounts and engine mounts. Had been wanting to do them anyway for awhile.

Did the body mounts, but the fan is still hitting radiator under the same conditions.

Did the engine mounts and now the fan is closer to the radiator. So, before I go for a spin, I'm trying to figure out two things:

1. Would a new Transmission mount potentially improve this situation?

2. Why is it only happening under acceleration?

Should I just chalk this whole thing up to a poor fitting aftermarket radiator?



Sent from my iPhone using Tapatalk

 

[gert]

It would not hurt to have a new Transmission mount anyway, bolt everything back in and leave the motor and Transmission mounts loose, also look into loosening the skod plate to get extra movement there if possible. you should have some wiggle room in the mounting holes to push the motor back, sounds like you need an inch clearance for yours. when you accelerate the crankshaft, Transmission internals, and driveshaft all spin which makes the motor strain against the motor/ Transmission mounts to push the Jeep forward, part of the reason you should have a torque arm attached with the Transmission mount is to help reduce the twisting on the motor and Transmission . Is there any play/ metal fatigue in the grill or front fenders? can you loosen the grille bolts and pull it forward a hair to help? I would say to compensate for the thickness difference in the aftermarket radiator at worst case slot the motor mount holes and Transmission mount holes so you can push it back enough to get the clearance you need. I know my AMC V8 is super tight against my Griffen radiator and I am planning to move my motor back enough to clear my electric fan which currently does not fit. good luck let us know how it goes.

 

[Kappy415]

Gert, thanks for the advice. I'll attempt (hopefully) all of this tomorrow. When you say 'slot the motor mount holes', do you mean move them backwards to a different, existing slot/hole on the brackets?


Sent from my iPhone using Tapatalk

 

[gert]

Gert, thanks for the advice. I'll attempt (hopefully) all of this tomorrow. When you say 'slot the motor mount holes', do you mean move them backwards to a different, existing slot/hole on the brackets?


Sent from my iPhone using Tapatalk

Having fuzzy grey mater problems right now but I think the skid plate has several sets of holes so you can try that but the motor mounts are slotted vertically so they would need a for aft slot as well


Sent from my iPhone using Tapatalk

 

[mriplaybass]

If you have a spacer between the fan and the water pump, you may be able to get a thinner spacer from your local parts house. I had the same problem on a AMC 304 . Got one from Advance Auto, problem solved. If you go this route, make sure the fan doesn't hit the water pump or anything else on the engine.

 

[gr8dain]

When I had my fan bore a hole in my radiator, I got an aluminum replacement and was able to mount it with the radiator flange inside of the grill rather than just bolted to the back of the grill. That gave me close to an inch more clearance. Just throwing that info out there in case nothing else works.

 

[DHugg]

I know this topic has been discussed before, but this time it's DIFFERENT (sort of).

I recently installed a new radiator, aftermarket, after determining it was the source of my cooling woes. The clearance is less than it was with the original but still 3/4"

Took several 75-100 mile trips and noticed the fan was hitting the shroud, but only when I accelerated quickly (either from a stop or in the middle of traffic).

A worn-out water pump was making lots of noise, leaking, and spinning off-center enough to make my AMC 304 AMC scar the radiator. New water pump cured it.

 

[Lumpy Grits]

Where is contact being made on the rad shroud?
Does the auto-Transmission use the same mounts as a manual tranny????......
Check the body mount bushing under the grill. See if the mounting bolt is missing. Also get and install one of the poly tranny mounts.
What's the condition of the torque arm bushing on the tranny?
You don't want any more than 1/8 inch space, above or below the t'arm bushing.
LG

 

[mtnwhlr]

I have a bad Transmission mount in my '84 and the last 4wheeling trip the fan hit the shroud and got stuck and started to over heat because it wasn't turning. So yes a bad Transmission mount could be your problem.

 

[Hedgehog]

What kind of fan did you get? Was it a flex fan?

 

[Kappy415]

Based on everyone's comments, I installed a new Transmission mount and torque arm bushing. As gert suggested, I loosened the motor mounts so that I could get as much flesh out of the driveline. But it didn't seem to help the overall affect as the test drive had the same result.

To answer your questions:
- The fan is striking the bottom of the fan shroud
- I tightened the bushing all the way down, there is no play.
- I have no spacer between fan and water pump
- Body bushing under the grill is present but in poor condition. I could only replace the bottom portion of the bushing when I replaced them. Marked the top portion as a to-do for a later date.
- My fan is stock, water pump is new

When I inspected the radiator today, I noticed a few things:
- the fan isn't impacting the radiator currently, only the fan shroud.
- the fan clutch had previously (there's a circle imprint on the radiator find perfectly in front of the fan clutch) impacted the radiator.

I took a couple measurements. The distance between the fan blades and radiator is 1". The distance between the fan clutch and radiator is less than a 0.5"

I'm tempted to dremel the fan shroud and chalk this up to an aftermarket radiator, but I'm still concerned about the distance.


Sent from my iPhone using Tapatalk

 

[Hedgehog]

Suggestion: The shroud is held in place with loose fitting "clip(?)" nuts. Loosen the fan shroud bolts and push the shroud down. You might find an extra 3/8" or so at the bottom of the shroud for the fan.

...... I ask again, what kind of fan did you replace the original one with? I am not a fan of flex fans or removing the fan clutch. Believe it or not, the fan clutch actually allows your engine to run cooler at speed. It also cushions the torque induced by the motor when accelerating or I suppose slowing down.

 

[Kappy415]

Hedgehog, I'll try that. To clarify I have everything set up correctly, the fan shroud bolts go through the fan shroud, then radiator flange, and then into the "clip nuts". Right?

And I didn't replace the fan. It's the stock fan with 7 blades


Sent from my iPhone using Tapatalk

 

[gr8dain]

What kind of radiator did you install as the replacement? Is it thinker than the stock one that went away?

 

[Belizean]

I slightly adjusted my fan shroud sometime back because an aftermarket radiator

 

[gert]

It's good to hear that only shroud getting hit, see if you can shim the motor up with shims under the mounts or slot the fan shroud mounting holes a little more that should get it fixed


Sent from my iPhone using Tapatalk

 

[JR74CJ5]

How tight are the top supports to the front grill? There are 2 "bars" that run from the firewall to the top L & R corners of the front "clip" or grill. If these worked loose with a worn bottom mount, your grill may be some of the issue.

You "might" be able to cheat the top out just a hair, and make sure it's all tight and readjust the shroud a bit.

With that, and the bottom bushing replacement, you may fix the issue. Might be the front clip is the thing flexing, not the engine or fan... (fully anyways).

I recently installed a new radiator, aftermarket, after determining it was the source of my cooling woes. The clearance is less than it was with the original but still 3/4"

I think your main issue is the radiator is closer than it was, and 3/4" is not enough for the clearance for one reason or another...

 

[Lumpy Grits]

Does this Jeep have a body lift?
Not hard to lower the radiator 3/4-1" by redrilling the rad. mounting flanges.
LG

 

[yellow85cj]

Are the new body mounts OEM rubber? Or poly? The poly are usually a bit taller than the rubber. Move the body up (which moves the shroud up) but the engine stays at the same level. So the fan will hit the shroud. New grill mount will do the same.

New Transmission mount will most likely (if the old mount is currently squished) will tilt the engine down in the front, and again hit the shroud. If all the body bushings and Transmission mount are new and installed properly, the engine should only twist minimally.

If all is new, easiest way to solve the problem is the way that it is done when a body lift is installed, lower the shroud.

But you really need to find out what is allowing the drive train to torque so much.

 

[Kappy415]

As everyone since my last post mentioned, I slotted the fan shroud holes, and was able to push the shroud down enough to clear the fan. All seems well now, EXCEPT

I have some new engine noises and overheating at WOT on the highway, which wasn't happening before. I'm going to do some research and see if I can figure out what's going on.

Appreciate all the help with this.



Sent from my iPhone using Tapatalk