Cold piston slap, thicker oil?

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My FX has always had cold piston slap, not bad. it goes away as it warms up, but sounds like a diesel when ambient temps drop below 60ish. I typically run M1 0w40. Should I go to something thicker when cold? Living in Florida I don't exactly need cold weather protection.
 
Your oil is THICKEST when cold... It the slap goes away when things warm up(oil now thinner)...how would a thicker oil help that piston slap?
Or is it the temp of the piston/parts that matters?
 
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its probably the temp of the pistons that cause that. as they get hot they expand to the proper size/shape, as they are desighned to do.

so i could maybe see how using a thicker oil at start up could help cushion the piston slap, but who knows if it actually would work.

try it!
 
Can you use a 0w30? M1? That is what I would try, I am another who doesn't understand how a thicker oil would stop COLD piston slap. If you decide to go thicker and it helps please let me know, I would be surprised. M1 0w30 or the thicker Syntec 0w30 should do the trick. The Former being my choice, especially since we are getting towards our cold months. I had a neighbor with cold slap and I told him to go thinner and it was gone that day. Never had that issue again.
 
Try either a 10W40 dino or if you want synth,M1 10W40HM. I bet either of these will do the trick. I`d try the dino first. Let us know how it turns out.
 
As the owner of many 'slappers' I can tell you this. Get used to it. No oil is likely to help, as it's not clearances where oil is pressurized.

If it is real piston slap it will disappear very quickly, unlike a valve gear noise which can hang around a bit. On our engines it has absolutely no effect at all on the life or performance of the engine.
 
Originally Posted By: SteveSRT8
As the owner of many 'slappers' I can tell you this. Get used to it. No oil is likely to help, as it's not clearances where oil is pressurized.


There you go, in a nutshell...

I could maybe see thicker oil helping if the slap was slight but usually the only thing that stops it is piston expansion as it heats up... Piston slap is basically the piston rocking slightly in the cylinder and while it likely won't cause a issue, I'd give the engine a minute or so to get heat into the pistons before I'd drive it...
 
Originally Posted By: SteveSRT8
As the owner of many 'slappers' I can tell you this. Get used to it. No oil is likely to help, as it's not clearances where oil is pressurized.

If it is real piston slap it will disappear very quickly, unlike a valve gear noise which can hang around a bit. On our engines it has absolutely no effect at all on the life or performance of the engine.


Ditto.
 
We have two "slappers", a 2000 Chevy 3.1 and a 2004 Chevy 3.4, both slap loudly when cold, both quite down quickly, and fooling with different oils has never made a bit of difference that I can detect.
 
My 2nd 3000GT I owned "slapped" with thinner synths. Dino made it go away completely. Some engines just seem finicky for some reason.
 
My Tundra has had a cold piston tick for the last 115,000 miles with no changes, and I'm not worried about it. Some oils damp sound better than others, but there is really no reason to be concerned about the noise that goes away when warm. The aluminum pistons expand and contract more with heat changes than the cast iron block, so they're made to be loose when cold. No problem.
 
Nothing cures piston slap except newly designed pistons. Apparently it doesn't shorten the engine life so continue to use the oil spec'd for your engine.
 
I would think the thicker oil at Cold start-up would Fill loose clearances, and then as the pistons warm-up and Grow a bit, They themselves will fill the loose clearance enough to stop their Rocking.
 
Except, then you are running the risk of premature wear to other parts, sliding surfaces that are not getting adequate lubrication for maby only a milla-second or maby a Second or two! Oh, no,...especially if there are Gut-n-Tight clearances for everything else, like there would, or should be in a Japanese motor. Then alleviating Piston Slap with Thicker oil would actually be Slowly killing the motor. Of course, everything like climate, driving distance, driving style, etc have a Major impact as well, and a thicker oil for start-up Cold Piston Slap might not make a bit of differance to anything at all, but that.
 
When I ran Syntec 10W30 in my 98 3000GT (that`s the oil that gave it the slap) it seemed like it was loosing hp. I`m thinking the Syntec was too thin for that particular engine,making it lose some compression,because with the slightly thicker dino,the slap was gone and the power returned to the engine.
 
Originally Posted By: 84zmyfavorite
I would think the thicker oil at Cold start-up would Fill loose clearances, and then as the pistons warm-up and Grow a bit, They themselves will fill the loose clearance enough to stop their Rocking.
Yes, I have an 88 Cadillac 4.5 engine with 130,000 mi on it. Early on, it had that typical Caddie front main thump and some slight piston slap. I converted it over to Mobil 1 20-50. Been quiet for 100,000 mi.+. This is in Las Vegas where COLD weather is rare. John--Las Vegas
 
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