Loc: beaver land EH?
IMHO piston skirt slap primarily has to do with piston skirt to cylinder wall clearances.
This is dependent on various different things:
-intended clearances on a "run-in" under normal engine operating temperature
-any anomalies introduced during the manufacturing process (wrong selection of piston? excessive machining of the cylinder bore? wrong/excessive clearances due to wrongly selected piston materials (thermal-geometrical expansion properties), etc.
Most of the mass-produced modern engines that suffered from various degree of piston slaps straight from the factory has more to do with manufacturing process and/or the intended design requirements (e.g. GeeAmm had some engines, in the past, with intentionally more piston skirt to bore clearances, straight from the factory, etc.).
uneven wearing of piston skirts would make an otherwise mechanically-sound engine to gradually become noisy (piston slaps) when cold. This is quite prominent as the thermalcycling of alu-alloy pistons thermalcycling over many hundred thousands of miles and gradually losing their proper geo-thermal expension properties.
using higher viscosity oil to "dampen" this piston slapping sound (as opposed to using thinner oil) makes some sense in this case but not the "be all, end all" cure to the problem. For this matter still fundamentally relates to a higher-than-normal "cylinder bore to piston skirt" clearances to begin with.
(1 ) engines that already suffered from piston slap when cold, try a higher viscosity grade motor oil to dampen the sound.
(2 )engine, over time, will have increased cylinder bore-to-piston(skirt) wear and will experience cold piston slap....again: when that happens, owners can either resort to using the same viscosity grade like before or go slightly higher up if it becomes annoying.
You'll either live with it (the sound), send the engine in for a rebuild (with new/proper piston for proper clearances's sake), or else.
"Internet discussion boards act as echo chambers for conspiracy dittoheads" A.Allen
We have had quite a few 'slappers' move through here in our GMC fleet trucks.
One is still here at 400k miles. Works every day, no smoke, no oil consumption. I never found anything bad about the slap except a bit of noise. In our trucks they slap for around 30 seconds when cold and then quiet down, sometimes slapping a second or two as they fall back to idle from some higher rpms.
A complete non issue, as the motors apparently are not harmed at all. All our trucks now have fancy coated skirts like I put in my high performance engines.
"In a democracy, dissent is an act of faith." J. William Fulbright Best ET-12.79 @ 111 mph 4340 pounds, Street tires Just like we go to Publix
Loc: southeast US
Steve, Your "slap" is different from my "slap". I have no problems with idle, as the engine is noisy enough while cold to hear any slap. It's the light load at 1500-2000 RPM in the first couple of minutes of driving that produces audible knocking sound, just like pneumatic hammer, but obviously not as loud.
I'm sure it's probably benign, but it was not present in the car in the first 30,000 miles or so, it's clearly abnormal, and I would like it go away.
No, it's definitely not normal. I just traded a 2009 RAV4 2GR-FE with 43,500 miles and it never sounded anything like yours. I actually considered it to have one of the best engines I've ever owned, and can see why the put it in the new Lotus. I didn't particulary care for the rest of the RAV4 though. That's why we have a new 4Runner. I would unload the vehicle if Toyota can't help you Jacek.
2013 Toyota Tundra DC 4X4 5.7L FFV 2012 Toyota 4Runner 2WD SR5 2004 Honda S2000
Loc: southeast US
thanks for your comment.
I suspect I would not have the noise if not the screw-up in the dealer where they used 5W20 oil. I argued hard but they defended the infamous Toyota TSB, that could be read different ways, that 5W20 is OK in 2GR-FE. I decided not to change oil to thicker since it was winter time and I was not towing anything. It was a mistake. Sure enough, the noise started at the end of the 5W20 OCI (5000 miles or so).
Actually if you do some research, this noise is very common in camry, lexus, and sienna that specify 5W20 and rare in RAV4 with it's 5W30 specification.
I actually like my RAV4, minus the noises. While Toyota took care of the tranny noise, they didn't budge on the engine noise.
Don't rule out a timing belt that has "elongated" or a tensioner which is worn. The 5 series Toyota 4 banger engine is known for some belt noise toward the end the belt life. Sounds awful, goes away with a new belt and tensioner.