Quiet engine and the Placebo Effect.

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Been a topic that's been up and down for decades on BITOG (early days before the myth was real, my 3VZE DID sound like a tin bucket of bearings after M1 0W40 was installed, and I posted it).

Anyway, noise differences and oils have been described as the placebo effect...to make it appear derived by the poster's imaginations.

Placebo effect, unfortunately isn't an imaginary cure, or a person imagining that they are healed...they actually are (*)

You can google "acoustic emissions engine oil viscosity" and find heaps of stuff...here's a table pulled from a paper. Remember that 3dB is a doubling of the sound pressure, so 6 is pretty decent.

engine%20noise%20viscosity.jpg


(*) As to the actual placebo effect, Gary Allan use to say that the art of medicine is keeping people entertained until nature takes it's course...I lump placebo effect in there...sometimes people heal themselves.
 
Right after an oil change, I think the engine runs quieter and smoother. Every time, all kinds of cars. Not imagination.
The human brain and hearing system is far more sophisticated than a decibel meter.
 
As the table shows it depends on the car.

Maybe how long you run the oil.

If some people don't experience it they could say yours is due to placebo.
 
Originally Posted By: camrydriver111
If some people don't experience it they could say yours is due to placebo.


Need to come up with a better term then...placebo is a real, measured effect due to no apparent cause.
 
IN my Nissan rogue
Cheap fake grpiii syn = LOUD and wearing, Magnetec SS = pretty darn quiet. On many high detergent LL oils IME the motor doesn't quiet and settle until about 2oookm down the road. The Moth long add pack "changeover" moving from surface competition embattled mode to "can we all get along now mate!" mode.
 
Last edited:
Originally Posted By: ARCOgraphite
IN my Nissan rogue
Cheap fake grpiii syn = LOUD and wearing, Magnetec SS = pretty darn quiet.



Does 'loud' necessarily mean more wear?
 
Depends on what's making the noise. Its hard to make a noise without contact at least approaching monolayer wetting of contact area.
Reacll "Try to clap hands under water make no sound or slap" or "drop plywood on floor viscous protection." If engine is clattering one might think your EP package is going into overdrive.

What scares me is the wear allowance on API certified oil allow a nitride layer on a cam to be worn off and PASS.

Anyone have a robust paper and study , "Noise doesn't = wear, Dummy!" ? I haven't read it. Goes against any stellar engine mechanics with a stellar rep and tuner intuition for the last 150 years. Harmonic motion should make harmonic noise. You hear non harmonic dissonance = failure in progress.
 
Interesting. The logical answer is as you state - more noise or noisier than before = wear. I just haven't seen any definitive studies either.
 
Agreed
Also if you do a fresh oil change before a trip and you use the same exact products you get worse mileage until it gets churned up a bit..........
On a new Ford V8 I went from 5w20 Castrol Mag to the 5W30 Blend.
Of course its fresh oil but I noticed less noise but it now takes the truck far longer to settle into the 500 RPM idle.

Also I hear other noises because the engine is quieter.
That said- after I burn this oil out I will go back to the 5w20 as it gets very cold here lately and I want the truck to get down to idle quicker.

Plus I honestly feel some drag with the 5w30 but it may go away as I only have 500 miles on the new brew.

Also lets be honest- most middle aged men can't hear worth a hoot and some are so rough they cant decipher much of anything. ask their wives
smile.gif
 
Sounds like we need a couple of UOAs from an engine, one with a "loud" oil and one with a "quiet" oil.
 
Good idea!!!!!!!

Originally Posted By: Kuato
Sounds like we need a couple of UOAs from an engine, one with a "loud" oil and one with a "quiet" oil.
 
Everyone seems to be ignoring the most interesting things in that table:

1) "right after" an oil change is frequently louder than a week after an oil change.

2) Of the cases where the change to a 'shear stable 10w40' made absolutely no difference, one of them had SAE 20 oil prior to the change.

My conclusion: there's not nearly enough evidence in that table to show a definitive correlation with anything.
 
Originally Posted By: wemay
Originally Posted By: ARCOgraphite
IN my Nissan rogue
Cheap fake grpiii syn = LOUD and wearing, Magnetec SS = pretty darn quiet.



Does 'loud' necessarily mean more wear?
What causes wear ?
 
Owned approx 30 different cars over the past 40 years. Cannot recall a single instance where the car was more quiet or noisy following an oil change. And I routinely changed brands from OCI to OCI. My current cars are very quiet on their present diets of PP and M1. I've had at least 4-5 different oils and grades in the 2002 since I bought it in 2009 (FSS 5w-20, VWB 5w-20, PP 5w-30, Monroe bulk oil, Indy garage bulk oil, etc.).

If either car did become noisier, I'll notice. If they got any quieter, I wouldn't notice.
 
Some people have much better hearing than others.
The high tones get lost first just saying.
Brand new my SUV sounded like a sewing machine I really thought it was going to die and was told its normal from the dealer.
Its running M1 right now and so much quieter its nuts.
Next OCI Im running Castrol EDGE Extended Performance hopefully it will be even better for the noise.
 
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