Engine sounds and drives way better after oil change

[demarpaint]

Originally Posted by PimTac
Since this subject comes up pretty frequently here I thought I would provide some evidence. This is still not scientific but it's a step up from just "earsay".

I just changed my oil in the Mazda. The engine was warmed up. I used a decibel reading app in my iPhone to see what difference if any there was between old and new oil. I had the phone in the same spot for each reading.

With the old oil the average reading was 74.4 decibels. The new oil average reading was 73.8 decibels.

Now, did the engine sound quieter to me? I will say yes but the decibel readings are not significantly that far apart to make a difference. My guess is that it's a difference tone or frequency of noise.

So based on all this, there is no difference.

Interesting! What was the temperature of the oil when you took the first reading, and the second reading? I wonder if that would impact anything?

 

[PimTac]

That I don't know. The engine was warmed up when I drained it and the new oil must have been around the outside temperature of 45 degrees. I did the usual start up and run for a few minutes to check for leaks before buttoning up the access panel in the splash shield. It took about a hour and 15 minutes to change the oil.

 

[TheLawnRanger]

I think an oil change can change an engine's sound and performance at times. I used to notice this with my truck when I first got it. As it turned out, it was using about a half quart of oil after 5-6k miles. I think getting the oil back to full is what made the difference as I don't notice a change since I started topping off in the middle of my OCI.

 

[JeffKeryk]

Originally Posted by 4WD
Jeff… does your Tesla sound quieter right after you charge it … ?

Dunno. Still trying to service the oil. Can't even find the dang oil filter. I am pretty sure it is a Fram 7317. Orange can of course.
You are just gonna have to come over and take it for a spin.

 

[tblt44]

I have tried at least 8 different oils in my 2003 5.3 over the years.
I dont feel a difference in any.
I have a 2003 with slight piston slap and no oil has calmed it down.
For close to 30 seconds with all oil it tics.

 

[ARCOgraphite]

Originally Posted by demarpaint
Originally Posted by PimTac
Since this subject comes up pretty frequently here I thought I would provide some evidence. This is still not scientific but it's a step up from just "earsay".

I just changed my oil in the Mazda. The engine was warmed up. I used a decibel reading app in my iPhone to see what difference if any there was between old and new oil. I had the phone in the same spot for each reading.

With the old oil the average reading was 74.4 decibels. The new oil average reading was 73.8 decibels.

Now, did the engine sound quieter to me? I will say yes but the decibel readings are not significantly that far apart to make a difference. My guess is that it's a difference tone or frequency of noise.

So based on all this, there is no difference.

Interesting! What was the temperature of the oil when you took the first reading, and the second reading? I wonder if that would impact anything?


That a good first effort but
The effort to get repeatable and usable results would require measurents at multiple locations and also the use of a spectrum analyser to pinpoint the "offending" tones, usually higher in frequency with short peaks often glossed over..

It ain't that simple of a correlation.

They Audio industry couldnt or wouldnt find a good measure of distortion for Stereo Power Amplifiers for decades.

 

[demarpaint]

Originally Posted by ARCOgraphite
Originally Posted by demarpaint
Originally Posted by PimTac
Since this subject comes up pretty frequently here I thought I would provide some evidence. This is still not scientific but it's a step up from just "earsay".

I just changed my oil in the Mazda. The engine was warmed up. I used a decibel reading app in my iPhone to see what difference if any there was between old and new oil. I had the phone in the same spot for each reading.

With the old oil the average reading was 74.4 decibels. The new oil average reading was 73.8 decibels.

Now, did the engine sound quieter to me? I will say yes but the decibel readings are not significantly that far apart to make a difference. My guess is that it's a difference tone or frequency of noise.

So based on all this, there is no difference.

Interesting! What was the temperature of the oil when you took the first reading, and the second reading? I wonder if that would impact anything?


That a good first effort but
The effort to get repeatable and usable results would require measurents at multiple locations and also the use of a spectrum analyser to pinpoint the "offending" tones, usually higher in frequency with short peaks often glossed over..

It ain't that simple of a correlation.

They Audio industry couldnt or wouldnt find a good measure of distortion for Stereo Power Amplifiers for decades.

My thoughts are the fresh, colder, "thicker" oil would have reduced sound, at least until it reached operating temps and the sound level rise slightly again.