Engine/Transmission (1994 - 1998) 98 12v engine moaning/humming/droning noise

[UhhhDawson]

hey fellers. my 98 12v w/150k makes a noise i cant figure out at certain rpm. from a stop i start accelerating and around 1500 rpm this sort of low to mid droning/humming noise kicks in out of nowhere and gets higher in pitch up to around 2100 rpm. it isnt a click or tap as if its anything metal, it just sounds like maybe something spinning really fast and rubbing something or spinning and being out of round causing the hum. i know im not very good at explaining it and maybe no one else has heard it. let me know if you need more details, i would appreciate any insight, thanks

 

[ttbird]

auto or stick? Any mods or stock?

 

[ndurbin]

Check the play on your turbo. Lil up and down is ok (stress the LIL), excessive is bad and so is any in/out movement. Also look at the housing around the fins for rub spots and check the fins for cracks or being bent.

 

[UhhhDawson]

auto trans. only mod is k&n intake system, other than that bone stock. the k&n makes the turbo whistle really loud, but the noise doesnt seem to have any correlation to what the turbo does

 

[JGK]

What is the condition of your tires? Does the road surface make any difference (smooth, well traveled pavement vs rougher stuff, like after chip sealing)? Mine are worn and I'm noticing odd noises and vibrations that I think are tire related.



If you can, get it up to speed where it is heard/felt and take it out of gear and let it coast at idle. Does it continue/stop/change?



Does it make a difference if going up hill (load on engine) vs downhill (no load)?



Answers to these may help determine if its wheel or axle related or engine related.



-Jay

 

[DSahd]

Check your load body for any loose bolts. I have heard them hum/you know what I mean.

 

[Vaughn MacKenzie]

Welcome to TDR. A word of caution about the K&N . . . keep a very close eye on it! I did the K&N thing on my '01 once and it did a very poor job of filtering. It let quite a bit of dust through. Most K&Ns are OK, but many are not, Cummins strongly recommends against them. If you want a good air filter like a K&N go with AFE.



Vaughn