Bad Bearing Type Noise, Can’t Find Source

[egamI_rorriM]

Hello ETCG forum,

I have been having this problem consistently for over a year now and am stumped to the cause. I am hoping someone on the forum has had a similar problem and can give some pointers on what could be the cause.

I have posted a video showing the issue here: http://tinyurl.com/69t64h8

So this happens is when the engine is cold, such as first start up after sitting over night. Once the car starts to warm up the sound will start to get quieter and after about 10 minutes will completely disappear. As you can hear the sound changes pitch when RPMs increase so i first thought it was one of my accessory belts.

I have done the following diagnostics:

Removed ALL accessory belts (Power steering, alternator and A/C) and the sound still happens.

Next I replaced the timing belt/water pump/tensioner (with brand new OEM parts from the dealer) and after all these were replaced the sound still happened. I had to replace them anyway since my water pump seal was bad and was leaking coolant.

So I’m now at a loss to what it could be. I hope someone has an idea what this could be.

Thank you for your time.

Regards,
Justin

Edit: Car details as follows

Car: 1987 Acura Legend 2.7L V6
Engine code: C27A
Chassis code: KA3
Transmission: 5 speed manual

Topic

[Trcustoms719]

Quoted From egamI_rorriM:

Sickboy:
I have tried using a stethoscope but i can’t pin point it. It sounds like it’s coming from the front camshaft (the one in the video). I looked a the service manual and behind that camshaft is the camshaft position sensor. Could it be possible that it’s rubbing on that sensor?

Trcustoms719:
If i push in the clutch the sound does not change and still happens.

Nah.., I don’t think the cam sensor would do this.
The only other thing i can think of is the oil pump, that can make a bad bearing type sound when it goes bad.

[egamI_rorriM]

Ouch, the oil pump is a pain to replace in this car, not to mention expensive, cheapest place i could find was around $600 for a pump. Is there a test to verify if the pump is failing?

[619DioFan]

If something was rubbing it would probably make the sound constantly . I could not hear the sound too clearly from the vid you posted but you might want to do an oil pressure test ( how many miles on the engine ? ) test it cold and watch the pressure guage as engine temp rises. perhaps you have an oil flow prob but once the pressure rises and the oil reaches all the moving parts ( upper valve train comes to mind ) things quiet down. again since I could not hear the noise clearly I am just guessing.

[egamI_rorriM]

I’ll get an oil pressure tester and check the pressure as it warms up.

The engine has 178,000KM on it (112000 miles).

[jbone]

Try a new oil filter, ….good quality one

[Trcustoms719]

Let us know how the oil pressure test goes!

[sickboy]

Hey there. I would suggest you buy a 5 buck or less stethoscope from your auto store or something like a Harbor Freight and probe around those areas when you have the conditions for the problem. This should help you narrow down your search.

[Trcustoms719]

Does the sound go away if you push in the clutch?

[egamI_rorriM]

Sickboy:
I have tried using a stethoscope but i can’t pin point it. It sounds like it’s coming from the front camshaft (the one in the video). I looked a the service manual and behind that camshaft is the camshaft position sensor. Could it be possible that it’s rubbing on that sensor?

Trcustoms719:
If i push in the clutch the sound does not change and still happens.

[dreamer2355]

How is the steering? Does the sound intensify when your go from lock to lock with the steering wheel with the vehicle at idle?

[EricTheCarGuy]

First your timing belt tension is WAY loose and is probably causing the cams to ‘grumble’ as I hear in the video. As for the high pitched noise that sounds like power steering pump to me, it’s extremely important that you use Honda PS fluid. I know you say you removed the belts and still heard the nose but perhaps you could make a video with the belts removed.

Forget about the oil pump being the problem as that engine is not known for that, I’d be more inclined to think that the small plate on the crankshaft pulley that keeps the timing belt on track is not installed correctly. Fix the belt tension first before you jump time.

[egamI_rorriM]

The weather has been really bad these last few days. As soon as i can I’ll post another video with the belts removed.

Also this video was posted before I did the timing belt/water pump/tensioner replacement, in the new video i’ll show the tension of it. When we replaced the timing belt the crank pulley was not removed, so i don’t know how the plate could have been moved. The plate you are referring to is the washer i have circled in red in this picture.
[url=http://i404.photobucket.com/albums/pp130/sabot512/washer.jpg:4njnzwxb]

I also forgot to mention that the noise randomly happened one day when i turned the car on.

As for power steering fluid i only use Gunk branded Honda/Acura PS fluid as shown here. http://tinyurl.com/3nmsudo

[EricTheCarGuy]

Yea that’s the part I was talking about as you can see it’s important to install it correctly. I would be very surprised if the problem was related to the oil pump, I’m sure there is some other cause but to me it really sounded like the power steering.

[Author]

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