"Growling" noise @ idle - V6

[jstutz101]

I've noticed a strange "growling" noise coming from the engine compartment when idling under "load" such as the A/C is on or when I put the trans in drive. It's louder when the engine is cold and goes away as soon as I accelerate. My wife seems to really notice it when driving through a drive thru. The truck has 125,000 miles on it. It otherwise runs like a top.

Anyone else experience anything like that?

 

[ME08Runner]

Maybe an exhaust leak that closes up when the engine gets hot? No check engine light or anything like that, I take it?

 

[MikeInNH]

An exhaust leak is going to sound more like ticking. Many times it's mistaken for valve clatter.

Growling....not sure without actually hearing the sound. But my first guess would be the clutch-fan.

 

[jstutz101]

An exhaust leak is going to sound more like ticking. Many times it's mistaken for valve clatter.

Growling....not sure without actually hearing the sound. But my first guess would be the clutch-fan.

I'm leaning toward the clutch-fan also. The noise seems to be coming from that area. It's a hard noise to narrow down since the truck needs to be in gear to really get it "growling", with my luck I'll end up running myself over. It definetly has something to do with the truck being under a "load." When its just idling theres no noise.

Thanks for the replies!

 

[jstutz101]

Update

I got some time under the hood today. With the engine running in gear and air running I got my growl going. When the AC compressor kicks off the rattle goes away. Got to be the AC compressor. Not quite - if I push down hard on the alternator the noise goes away, almost like something is loose. :redbrick:

So, I guessing there has to be something common between the alternator and compressor that is causing the two to rumble. Maybe a loose mounting bracket?

The only good thing is everything seems to be working. No CEL's and the air is cold.

Any ideas?? :thanks:

 

[mrpanic7]

I got some time under the hood today. With the engine running in gear and air running I got my growl going. When the AC compressor kicks off the rattle goes away. Got to be the AC compressor. Not quite - if I push down hard on the alternator the noise goes away, almost like something is loose. :redbrick:

So, I guessing there has to be something common between the alternator and compressor that is causing the two to rumble. Maybe a loose mounting bracket?

The only good thing is everything seems to be working. No CEL's and the air is cold.

Any ideas?? :thanks:

Hey thats funny you put this up cuz mine started doing this too. havent had a chance to look at it, but yeah ive narrowed it down to being related to when the A/C compressor is used. So sitting at idle, once the A/C kicks on the low rumble happens. From the cabin it sounds more so on the passenger side of engine bay. Once A/C is off it goes away. Im going to play around with it tomorrow when i do the brakes and see if i can narrow it down. IF you find anything please share, ill make sure to do the same.

 

[kao]

Hmm... Mine slightly growls under load at morning when engine is cold just after putting trans in D.
Also whining noise comes from alternator area under 2000 RPM and higher. I've changed bearings but noise still comes. Perhaps, AC compressor is the reason.
No idea what to do, it is extremely hard to check AC bearings.

 

[xxaarraa]

I am going to revive this old thread since this is happening to me and driving me crazy for the last 3 months. I PM'd the OP but haven't heard back yet. If anyone's got any experience or thoughts, please share. I would be very grateful.

Already did two trips to dealer and they can't isolate it. I have replaced a y-pipe gasket, have two more exhaust system gaskets on hand, and desperately trying to hunt this down and solve it. My thread:

http://www.toyota-4runner.org/4th-gen-t4rs/198990-yet-another-4th-gen-cat-rattle-thread.html

 

[jow]

Can a Youtube or pictures with sound be posted to share the sound? My best option with my old digital camera is a picture with the sound mode. The new will be a video clip (that might use too much memory.

My guess before hearing the noise will be belt or bearings. I hate to think the Dealer’s Mechanic had no suggestions. I’ll ck my V6 for a noise and see in any other ideas seems possible to help track the noise.

1. Is the water pump in the mileage window that the bearings could be bad? An excessive leak at the weep hole might help to detect this.
2. Is the belt known to wear to a point it causes a noise? Old School Belt Dressing might indicate wear.
3. Feeling for bearing play or roughness with the belt off is another past way of tracking noises.
4. The belt tensioner’s bearings is another item to consider and feel for play in.
5. At what mileage or yrs is the belt recommended to be change? Now would be good if needed.

 

[FAIRCLOUGH]

I've noticed a strange "growling" noise coming from the engine compartment when idling under "load" such as the A/C is on or when I put the trans in drive. It's louder when the engine is cold and goes away as soon as I accelerate. My wife seems to really notice it when driving through a drive thru. The truck has 125,000 miles on it. It otherwise runs like a top.

Anyone else experience anything like that?

Oh yes. It is a rattle that sounds like the exhaust pipe rattling against something but it is not that. Rattles louder when in park or even louder when in drive with brakes on.

 

[Mike07SE]

I bet it's the heat shielding under the truck. At this point all mine has been ripped out due to rattling under conditions mentioned in this thread.

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