Question for everybody.

I popped the hood yesterday because my truck sounded like it had an exhaust leak when I first started it. Was 46 yesterday morning....burrr.. ...anyway I couldn't find the leak and it went away pretty quick. Maybe the computer shutting down a cylinder to warm up the engine faster???

I happen to look at the fan while the truck was idling and my fan blade wobbles about a 1/4" to 3/8" in and out of the shroud. Fan is tight and smooth turning so I don't think this is a bad bearing but maybe a bent hub or shaft??? Does anybody else's do this? Maybe this might be the cause of the 2100 rpm A/C vibe, as the A/C locks in the fan. I remember reading in the shop manual about checking the fan for trueness by laying it on a flat surface and checking the height of the blades. That would seem kind of useless if a 3/8" run-out is acceptable..

If a couple guys or gals would check their fan blades at idle for run-out that would be great. Hopefully somebody that doesn't have the vibe and somebody that does.

The wobble is from the front to the back of the truck, I guess that would be a lateral run-out.

Thanks everybody!!

 

My fan runs true. I also don't think I've got that vib thats got everyone in a fuss either.

Then again, maybe I've been desensitized towards it now and don't even notice it.

 

FYI, there is a TSB for a loose cooling fan.

http://dodgeram.info/tsb/recalls/B28.htm

 

My fan has some run out also. I have a slight drone at 2100rpms but it's hardly noticable, with the A/C on or off.

MikeyB

 

Same as MikeyB


Sittenbull

 

this is a factory flaw and they know it. the fan and clutch are not installed by cummins. this maybe the cause of the vibration problem. if they dont fix the rear axle and vibration, I think I might try the new nissan or toyota. >

 

My fan has the exact same run out...right now I'm more concerned with the vibration in the floor problem...I think the fan will be much easier to resolve. :

 

I looked at mine this morning and it has about the same amount of runout as you mentioned. I also have an early build '03 with the cracked alternator bracket. I'm getting the bracket looked after tomorrow and I'll ask the dealer about the fan, as it could be setting up a vibration. The two could be related.

Brian

 

I had the cracked alternator bracket replaced today. The dealer called me and said somebody was going to have to pay for the bracket as there was nothing wrong with the old one, and they were upset they had ordered the parts on my phone call and not checking the truck themselves >, so I had to go to the service desk and show the guys the crack. Plain as day to me and to them as well once I showed them :-[. After the discussion at the desk the mechanic (not the service writer)thanked me for bringing it in to have it changed before it broke and caused more damage.

The mechanic addressed my concern of fan run out by telling me the blades are cut at different thicknesses to avoid fan howl. I've not had time to look into that myself yet.

Brian