So... I have a. '03 Subaru Forester 2.5x. I'm the second owner, vehicle has 113k on it and I've had it since 95k. Pretty clear that the previous owner didn't take very good care of it.
Anyways... Subaru piston slap. Sounds god awful when it's cold. And I'm really not exaggerating when I say it sounds like a diesel sometimes. Goes away when it warmed up. Engine doesn't use any measurable amount of oil between oil changes, nor does it leak.
I've tried using 5w-30 synthetic oil. Valvoline synpower. The cold piston slap nearly went away after about 800mi of driving with a bottle of MoS2 in the oil and enough ZDDPlus to bring the phosphorous concentration up to 1400ppm.
So fast forward to the next oil change. I decided to try something a little bit thicker to see. Rotella T6. Once again, with a bottle of MoS2 and enough ZDDPlus to boost the phosphorous levels.
It seems like the piston slap got louder after switching to something a bit thicker. No notable difference when warm, but it sounded pretty lackluster when the motor was cold.
So now... I'm considering trying something that's a bit thinner when cold. Perhaps a 0w-30 oil to see if that makes any difference. I'm a bit leary of going below a 30 weight oil - or even a mix of 30 and 20, for fear of losing oil pressure when warm.
So yeah there's my brain dump. Thoughts/opinions/warnings/berations? I'm in the pacific NW. Not really much in the way of extreme temperatures either way. Most summer days are 90 degrees on the warm side, anything above 100 is a rarity. Winter nights are generally between 20 and 25, with 45 or so temps during the day. Single digits for maybe 1 night out of the year
Anyways... Subaru piston slap. Sounds god awful when it's cold. And I'm really not exaggerating when I say it sounds like a diesel sometimes. Goes away when it warmed up. Engine doesn't use any measurable amount of oil between oil changes, nor does it leak.
I've tried using 5w-30 synthetic oil. Valvoline synpower. The cold piston slap nearly went away after about 800mi of driving with a bottle of MoS2 in the oil and enough ZDDPlus to bring the phosphorous concentration up to 1400ppm.
So fast forward to the next oil change. I decided to try something a little bit thicker to see. Rotella T6. Once again, with a bottle of MoS2 and enough ZDDPlus to boost the phosphorous levels.
It seems like the piston slap got louder after switching to something a bit thicker. No notable difference when warm, but it sounded pretty lackluster when the motor was cold.
So now... I'm considering trying something that's a bit thinner when cold. Perhaps a 0w-30 oil to see if that makes any difference. I'm a bit leary of going below a 30 weight oil - or even a mix of 30 and 20, for fear of losing oil pressure when warm.
So yeah there's my brain dump. Thoughts/opinions/warnings/berations? I'm in the pacific NW. Not really much in the way of extreme temperatures either way. Most summer days are 90 degrees on the warm side, anything above 100 is a rarity. Winter nights are generally between 20 and 25, with 45 or so temps during the day. Single digits for maybe 1 night out of the year
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