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Hemi huming noise driving me insane Help!!

4K views 30 replies 9 participants last post by  wicked70496dart 
#1 · (Edited)
I have a humming/whinning noise coming from my dodge. The noise doesnt start until the vehicle gets warm. Sounds excellant when its cold. It sounds to be coming from under the floorboard towards the back of the engine/bottom. This motor only has 29,000 on it and I cannot figure it out. So far to date this is what was done and still didnt solve it.

1 The belt was taken off and the truck was run without the belt and the
noise still persisted.
2. The cats and y pipe were changed
3. Front rear main seal was changed

The noise is there whether or not the truck is in gear or in park. Sound is consant at idle but sounds a little faster when reved up almost as if something is spinning. One garage told me that the sound is normal which I know is not. Second garage told me that it could be a valve guide or rocker shaft issue but they would need to take the head out and look at it costing me around $500.00. Another says toque convertor or trans pump. They say the can hear it the loudest on he y pipe. I found this video which is the exact same situation and sound as mine, what do you guys belive it could be?


http://www.youtube.com/watch?v=rg3dvnqZWag
 
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#2 ·
First when I read this I was thinking something with the fuel system, recirculation, pump, or regulator. When I listen to the video it sounds more of a growling or mechanical. Which leads me to think trans.

Also maybe something with the AC since a lot plumbing is in the vicinity.

Good luck. I Know that stuff drives me crazy.
 
#9 ·
Nothing happens when I turn the steering wheel, hum/whine sound stays the same. I havent changed the oil yet since I bought it, do you think it could be the wrong oil? What is best synthetic or conventional? Pitch doesnt changes much as its hard to tell when you give it gas it might get slightly louder but not much. The noise stays the same from park to drive, it does not change.
 
#10 ·
Fairly certain it's the egr. My hemi start making similar noise with a po406 code. I deleted it and it doesn't come on all the time. However I also know when it needs an oil change by the engine whining. Fresh oil I get a lift tap, showing variable timing. Old oil it sounds louder and a brick for gas pedal. Try full synthetic 5w-30 pennzoil with a full fresh tank of 89.

I am just a backyard mechanic who has been hooked on mopar for 25 years. However I can ensure you these hemi's run best on full synthetic. I get 4 miles per gallon better mpg.

I can say for certain it is engine related. Just start with the simple things first.
 
#11 ·
I would try the simple things first. Fresh full synthetic pennzoil 5w-20. And fresh tank of 89. If that doesn't help try some fuel system cleaner. Also check EGR.

My 07 loves 89 and full synthetic. Also I got an engine whining and she just popped an PO406 code. EGR. I deleted it and seems to last twenty to thirty cycles before showing up again. Very similar noise to yours.
 
#16 ·
Are you able to follow the y-pipe up to the exhaust manifold, especially the driver side? Is it louder there?

Also can you confirm that you have tried the oil pan and transmission oil pan?

What other area's by the engine have you tried?
 
#15 ·
The egr or Exhaust Gas Recirculation is a small canister on the front of the engine by the intake filter box. Honestly after listening to the video I doubt it is that. Exspecially if you say it is loudest or most definitive by the Y pipe. That being the case, maybe it is the oil pump or something top end. Usually fresh oil would alter the pitch in some way.

This is strange, very strange. :4-dontknow:

With 30k on that motor I really surprise that it would be a noisy pump, bearing, or anything.

Got me stumped.
 
#17 ·
The sound is loudest on the y pipe, it can also be heard on the drivers side valve cover slightly, at first i thought it was the cats but the dealer claims to have changed them. shop told me that they disconnected the trans and the sound was still present so it would rule out the transmision.
 
#18 ·
From the what you have described it appears that the issue is between the driver's side cylinder head to the y pipe.

I wouldn't take the dealer's word and I would still check between the y-pipe, including the catalytic converter to the exhaust manifold, etc. If you haven't tried either the oil pan or the transmission oil pan, I would still check it.
 
#19 ·
I checked the converters and they are new along with the y pipe so that was defiantly changed. The transmission was disconnected from the vehicle and the noise didntchange so that rules out any trans issue, I am really wondering if ts the oil pump making the noise as it gets hot. maybe i will just change that out and see.
 
#20 ·
Ok let's start over.

When did you first notice the noise? Did something happen or anything unusual happen when it first occurred?
How long has it been?
Has it gotten progressively worse?
Does it always get louder after the car has warmed up?
Has it changed since changing out the the cats and y pipe?

I personally would still check the cat and y-pipe and any work done by someone else. You don't know if they accidentally dropped a bolt or nut into the exhaust system when changing it. Even though it's new, you never know if it could be a bad new y-pipe and cat installed. I would go through the effort to completely rule it out. It shouldn't take much time to do.

I just hate to see you keep throwing money on replacing different parts that aren't solving the problem.

I don't think it's the oil pump only because the oil pump sits in front of your crankshaft and is at the front of the engine (Based on what you said before it sound like it's coming from the floorboard). Look at the big pulley at the bottom for the crankshaft. The oil pump is behind it but in front of the timing chain.
 
#21 ·
I noticed the sound 15 minutes after I left the dealership. Went right back and they pulled it into the garage. First they ran the truck without the belt and it still made the noise so they ruled out pulleys and accesories. Next they listened with the scope and stated that the noise is loudest on the y pipe so they changed the y pipe and cats and it still made the sound, so they the went ahead and changed the front rear main seal and that did not change the sound. Transmission issue has ben ruled out as aamco disconected the transmission from te engin so that rud out torque convertor and trans pump. The nois does not appar at all for the first ten minutes or so but then apears once the vehicle reaches its full operating temperature. The noise doesnt appear to change in pitch much ith only a slight change hen the engine is reved up a little. I was thinkin oil pump but the noise isnt in the front its more noticeable in the back side undearneath. someone else is saying could be in the valve train like a valve guide. I am lost on this problem.
 
#22 ·
My bad. I assumed your were mechanically inclined and was checking all of this yourself.

I think the issue may have to do with the exhaust manifold. A common issue is the exhaust manifold studs/bolts breaking or working themselves loose.

You will want at least a smoke test done, especially after the truck has warmed up and the noise is present. If they don't find anything I would ask them to put a wrench on every exhaust manifold bolt to see if any are broken or loose.

Before your y-pipe and cat were replaced did you have an aftermarket exhaust installed?
 
#25 ·
Reset computer

Any change when you disconnect the negative battery terminal for five minutes and then restart?

A lot things are voltage related in issues. How fresh is the battery? Check cells and voltage between them. Battery should be even with 13+ volts total.

These trucks should throw codes when the slightest thing is off. Has the ECU been tuned or manipulated by others? Can you use a scan gage to determine MAP pressures, and Fuel pressures and or see if pending codes are available.
 
#27 ·
I had a new battery installed the other day cause the old one was only putting out 330cca, no change, there are no codes stored in the computer either. I belive the dealer flashed the computer when it was in. What type oil and filter do you reccomend?
 
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