Is the oil protecting even when engine is noisey?

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Mar 16, 2003
It seems that a lot of folks have some engine noise like piston slap, valve chatter and such using Mobil 1 because it is on the thin side. Some people's engines quiet down a bit when they switch to a thicker oil/different brand and same weight. What I'm asking is if an engine is making noise using Mobil 1 and then you switch to a(lesser) different oil even a dino oil and the engine quiets down does that mean the engine is being protected better then when using M1 even if it's a dino oil?
I don't think so.

It would seem all its doing (if really doing anything) is masking the noise. I am no expert but I have seen this piston slap condition first hand and no oil I(we) have tried has had any effect on the noise whatsoever. We have tried 0W-30,5W-30, 10W30 and 10W40 from regular dino oil to 100% synthetic. About the only thing we noticed is the synthetic's gave us instant oil pressure wheras most of the regular oil had a few seconds lag in oil pressure build-up.

I realize there are some if not many who will not agree with this but sometimes I wonder if what they are experiencing is wishful thinking. My friends 1999 Chevy has had a cold knock since is was new and he now has around 75,000+ miles. Not one engine problem so far and he says the noise is related to the ambient temp. The cold is is, the louder and longer the duration of the noise. Warmed weather makes it hardly noticable.
I would estimate that 90% of of subjective engine noise reduction by oil is directly related to the sound absorbing qualities of the lube. That factor is almost always related to viscosity.

Thicker oil absorbs noise more than thinner oil.

Thus M1 gets a bad rap for allowing more noise.

Engine noises evaluation are akin to sniffing oil as many here like to do !

Analysis is a better indicator to determine if noise is related to wear generation or a developing problem.

For instance in my case as my hearing is degrading my engines all sound much smoother and obviously run better !!!!
I think's just annoying. Funny thing reading the AMG article in the current Car and Driver (or Road and Track) and they mentioned engine noises/sounds...I just thought of the salad oil M-1.

Certainly lab tests/UOA show otherwise, but I will say that M-1 is a strange beast and they must leave stuff out (addatives) that's otherwise found in other oils becauase theirs is the only OTC "PAO" and so it doesn't need it.
If you switch oils and get MORE NOISE, I think that's bad. You should switch back ... or if you try a new oil (of the same weight) and engine clatter decreases, that's good.

This what I noticed when I swtiched FROM Mobil 1/ Valvoline Synpower TO Red Line (all were 5W30 or 10W30).

All else being equal (and that's almost NEVER the case) less noise is good. However, Terry is right, conjecture-laden anecdotal evidence is not a substitute for professional used oil analysis.

Having said that, the "piston slap" noise a lot of people are hearing these days during cold starts is annoying, and often an indicator of some wear, but it is not a sign of imminent engine failure.

--- Bror Jace
Thanks for the replys guys! I'll have to just do a little testing and UOA of my own in the future and see what they say!
Loud stereos can cure all kinds of problems. I have squeaky rear brakes, but when I turn up the stereo, it magically is gone!
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