Rough engine idling with Amsoil

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Apr 17, 2003
I used both AMsoil S2K 0W30 and M1 0w20 on my new Honda V6. I find that the engine idles obviously more rough( more vibration) with AMsoil oil than the M1.
Any explanation? More vibration mean more wear?


Seems very odd. The 0W-30 has a slightly higher viscosity than the 0W-20 so I suppose it could effect the idle if something was amiss with the ECU. Can't jump to any conclusions about wear, though. Tell me a little more about miles on each oil, on the car, etc...
Something changed somewhere in the engine. I'm not a fan of Amsoil. I have never used it but I can't see why it would cause your engine to idle rough over the M1. I could see if you were using a heavy dino oil producing a rough idle but not with a synthetic. I have driven over 750K miles on dino in Volvo 4 cylinder Turbos. I can say one thing the engine in my present Volvo filled with M1 runs smoother than any of the other three Volvo Turbos I owned before that were filled with 10W30 dino. Amsoil and M1 are both quality synthetics and there should not be any real perceived difference between them. Your engine should not be able to tell the difference.
Umm, why is this abnormal? My car (2001 Prelude) idles much smoother with Amsoil 0W-30 than 10W-30. My parent's car (2002 Passat V6) idles much smoother with Amsoil 10W-40 than with dealer's dino 15W-40. All cars are different and react differently to specific oils. You just have to find one that's best suited for your car...
Hello Dan,

Try switching the Amsoil back in the engine a few times while also switching the Mobil in between
the Amsoil switches. See if the engine runs rough every time the Amsoil is put into the engine, this should clear up if the engine just does not like the Amsoil or if there was something
else going on.
I really think something else was going on,
I remember a few years back, friend put Amsoil
into his Honda and a couple of days later the battery went dead. Jokingly, he said maybe the Amsoil fluid was negatively charged and drain his battery somehow or another.
The car specs a 5w20. And if I recall correctly, amsoil 30wt's tend to be on the heavier end. Just food for thought.

The 2003 car has 7000 miles on it. Miles on Amsoil is about 500 miles now. I had about 2000 miles on the M1. Both M1 and Amsoil do not give a 'big' rough idling. They both are doing fine in a normal standard. Should be better than dino. I just try to compare the two. I find that I can feel the engine idling(an obvious vibration) from my seat with AMsoil and I hardly feel the vibration from my seat when with M1. M1 seems run more smooth in this engine, although I am concern about it may be too thin.
Could it be due to viscosity of Amsoil which is higer, therefore more friction? Or because it does not have Moly in it?
This makes no sense!! Are you sure you did not bump something in the engine compartment.

I have heard of all kinds if paranoid things persons have come up with when changing oil, but in all due respect, this one takes the cake.
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