Don Green Posted January 26, 2020 Share Posted January 26, 2020 I have a 2006 granite I purchased new in 2008 for local use only 54000 miles on truck. All of a sudden it started making a very noticeable humming noise at idle and oil had a smell like burnt plastic, I can't find the problem, removed fan belts no change,removed power steering pump same, oil spinner filter,air brake compressors same noise. replaced oil pump (found wear marks on release valve) now noise is not as loud but still there. Not in trans or clutch (same when clutch is pushed in) Afraid to keep running and have major problems. I even had a mack tech look at it and he pretty much didn't have a clue Anyone ever experienced this problem. Thanks for any help Quote Link to comment https://www.bigmacktrucks.com/topic/60707-ami-370-engine-humming-noise/ Share on other sites More sharing options...
Mack Technician Posted January 26, 2020 Share Posted January 26, 2020 You do an oil test? Does it go away when you Rev above idle? Quote Link to comment https://www.bigmacktrucks.com/topic/60707-ami-370-engine-humming-noise/#findComment-441332 Share on other sites More sharing options...
mrgumby Posted January 26, 2020 Share Posted January 26, 2020 Does it have an electric fan clutch? Quote Link to comment https://www.bigmacktrucks.com/topic/60707-ami-370-engine-humming-noise/#findComment-441333 Share on other sites More sharing options...
Don Green Posted January 26, 2020 Author Share Posted January 26, 2020 Don't hear it above idle but naturally normal engine sound takes over Quote Link to comment https://www.bigmacktrucks.com/topic/60707-ami-370-engine-humming-noise/#findComment-441334 Share on other sites More sharing options...
Don Green Posted January 26, 2020 Author Share Posted January 26, 2020 (edited) When fan belts are removed (fan not turning)doesn't change Edited January 26, 2020 by Don Green Spelling Quote Link to comment https://www.bigmacktrucks.com/topic/60707-ami-370-engine-humming-noise/#findComment-441335 Share on other sites More sharing options...
Don Green Posted January 26, 2020 Author Share Posted January 26, 2020 Did not do oil test but did start day after oil change Quote Link to comment https://www.bigmacktrucks.com/topic/60707-ami-370-engine-humming-noise/#findComment-441336 Share on other sites More sharing options...
david wild Posted January 26, 2020 Share Posted January 26, 2020 You got a hummer eh ? Quote Link to comment https://www.bigmacktrucks.com/topic/60707-ami-370-engine-humming-noise/#findComment-441338 Share on other sites More sharing options...
Mack Technician Posted January 26, 2020 Share Posted January 26, 2020 Couldn’t help yourself Wild Dave.... 🙄 1 Quote Link to comment https://www.bigmacktrucks.com/topic/60707-ami-370-engine-humming-noise/#findComment-441341 Share on other sites More sharing options...
Don Green Posted January 26, 2020 Author Share Posted January 26, 2020 9 minutes ago, david wild said: You got a hummer eh ? No comment Quote Link to comment https://www.bigmacktrucks.com/topic/60707-ami-370-engine-humming-noise/#findComment-441342 Share on other sites More sharing options...
mrgumby Posted January 26, 2020 Share Posted January 26, 2020 Got an asset 460 that smells with fresh oil in it always did for some reason. 310.000 on it and it always smells with fresh oil but not like rubber Have you cleaned the breather element? Don’t know about the noise got a video of it. Smellavision would be good Couldn’t help myself Quote Link to comment https://www.bigmacktrucks.com/topic/60707-ami-370-engine-humming-noise/#findComment-441343 Share on other sites More sharing options...
Don Green Posted January 26, 2020 Author Share Posted January 26, 2020 I did check the breather element. When oil pan was off everything looks like new other than scuff marks on pressure relief valve on pump, new oil and filters again. Quote Link to comment https://www.bigmacktrucks.com/topic/60707-ami-370-engine-humming-noise/#findComment-441368 Share on other sites More sharing options...
fjh Posted January 26, 2020 Share Posted January 26, 2020 I know you said you pulled the belts however when this model first came out fan hub bearings were an issue for a time! Can you tell which the direction the humm is coming from! ? If the bearings in the hub were bad you could stand mid rad and hear it at idle! Quote Link to comment https://www.bigmacktrucks.com/topic/60707-ami-370-engine-humming-noise/#findComment-441376 Share on other sites More sharing options...
OldRedMack Posted January 26, 2020 Share Posted January 26, 2020 Check the belt tensioner pulley. Quote Link to comment https://www.bigmacktrucks.com/topic/60707-ami-370-engine-humming-noise/#findComment-441377 Share on other sites More sharing options...
david wild Posted January 26, 2020 Share Posted January 26, 2020 Hey I asked why my 98 E7 clanks so loud, drives me nuts, Mack shop said it sounds good, they can not even tell me what makes the clanking sound, I find it I will try to get rid of it. Truck runs great oil stays really clean just clanks. Quote Link to comment https://www.bigmacktrucks.com/topic/60707-ami-370-engine-humming-noise/#findComment-441387 Share on other sites More sharing options...
Don Green Posted January 26, 2020 Author Share Posted January 26, 2020 4 hours ago, fjh said: I know you said you pulled the belts however when this model first came out fan hub bearings were an issue for a time! Can you tell which the direction the humm is coming from! ? If the bearings in the hub were bad you could stand mid rad and hear it at idle! When you walk around around the truck sounds the same on both sides and front. When I took air brake compressor off and made a plate to cover engine block it was actually louder. Anyone ever heard of any issues with the auxiliary shaft or timing gears. 18 hours ago, mrgumby said: Does it have an electric fan clutch? Quote Link to comment https://www.bigmacktrucks.com/topic/60707-ami-370-engine-humming-noise/#findComment-441396 Share on other sites More sharing options...
fjh Posted January 26, 2020 Share Posted January 26, 2020 We have seen the shafts gear break the oil pump will quit if this happens! Quote Link to comment https://www.bigmacktrucks.com/topic/60707-ami-370-engine-humming-noise/#findComment-441397 Share on other sites More sharing options...
alex g Posted September 7, 2020 Share Posted September 7, 2020 Has anyone come to a conclusion on this issue? I'm hearing a similar noise on my 2000 E7 350 Quote Link to comment https://www.bigmacktrucks.com/topic/60707-ami-370-engine-humming-noise/#findComment-460328 Share on other sites More sharing options...
alex g Posted September 7, 2020 Share Posted September 7, 2020 I've done similar tests unhooking fan belt. Put broom handle against areas on engine engaged clutch no change Nothing seems to sound odd. Truck operates fine just has a strange noise Quote Link to comment https://www.bigmacktrucks.com/topic/60707-ami-370-engine-humming-noise/#findComment-460329 Share on other sites More sharing options...
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