Banging/knocking noise at idle

[Leatherneck]

So I have this noise at idle, it is something sounds metal on metal but only at rpms below 1200. Any ideas on locating it before tearing apart? Engine runs good under throttle with no unusual noises.

[Marc]

Run the engine briefly with the fan belt off, if the noise is gone investigate the fan and hub.

[turbobaja]

How's the side play on your rocker arms/shafts? Does it sound like it's coming from one side or the other, or more central/internal?

[Leatherneck]

Thanks guys I will have a look at both. I appreciate the help.

[sparkmaster1]

loose straight cuts?

[Leatherneck]

I disconnected the alternator and engine sounded as it should. Next question is, I am looking at fans and I see them from $60 to $91

AC119031 Race Fan, Doghouse Fan With Welded Fins Your Price: $60.00

WELDED AND BALANCED COOLING FAN 35MM I.D. FAN - ALL DOGHOUSE STYLE Phone/Mail order Price US $87.95 Our Web Price US $74.95

01-98-2006-0 RACE FAN (WELDED), 71-ON, 36.8mm WIDE $ 75.95

Air Cooled VW Cooling Fan 36mm Tig Welded Racing Fan [CPR119103] $85.95

Part number 4586-10 Weight 2.95 lbs Sale price: $90.99

Do you guys have a preference?

[supaninja]

check your pulley, one of my buddies had the same sounds. His pulley was loose and had a huge crack in it. He spun a crank bearing and it took out the pulley

[Leatherneck]

check your pulley, one of my buddies had the same sounds. His pulley was loose and had a huge crack in it. He spun a crank bearing and it took out the pulley

Will do. Thanks! Running a Serpentine system so hope it isn't that.

[FJCamper]

Hi Leatherneck,

Spin the fan over by hand, engine off, and listen for scrape or rubbing sounds.

A noise here means the fan is slightly crooked somehow. I've seen the altenator pulled downward by very tight belts, which of course tilts the fan slightly inside the fan housing.

The quick & dirty fix is to shim one or more of the bolts or screws holding the fan and alt assembly to the fan housing with an extra washer to try and square up the alignment. Some guys have slipped a broad homemade shim (scrap aluminum etc) under the alternator to raise it up a bit from the alternator support.

All straight parts and proper assembly should mean no shimming is necessary -- but such is life.

FJC

[Leatherneck]

Thanks for all the input guys, helping me as well as those lurking too.

I took off the belt and noise went away, grabbed the alt pulley and twisted it, I have slop in the fan, something loosened, broke but whatever happened I need another one. I ordered a WELDED AND BALANCED COOLING FAN 35MM I.D. FAN. So I also don't have to worry about the stock one grenading itself. Again thank you for the help.