What oil for 2003 5.3 Vortec?

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My dad has a 2003 chevy silverado 1500 with the 5.3 . He has used Mobil 1 5W-30 since it was new with a wix filter. As many of you know this engine has the "piston slap" issue. I would like to stick with a synthetic if possible. The truck is at about 125,000 at present. He lives in seattle so it sees some cold weather but nothing too extreme. Your Opinions are appreciated!
 
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I see that you are using Redline in your Tacoma. Ask him to try that. My boss has the exact same motor and has tried many different brands and weights. The piston slap is always there. Some people have found some motor oils that have quieted it down significantly. Some others nots so lucky.
 
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If he like M1 products, I'd move up to either the 10W-30 HM version, OR M1 0w-40, to see if it will help the p/s issue.
 
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In my experience with GM engines (most of my life), they all had some sort of piston slap. Believe it or not, the thinner oils actually helped quiet them down. And I'm not talking thinner at operating temperature, but the thinnest at start-up (I know, the two are often related - unfortunately). My mother has a 2002 Chev Venture with the 3.4L V6 with about 170,000 miles. I use it every weekend for towing. It always had piston slap even since new (worse now though). I've tried pretty much everything in there, and the quietest oils were Amsoil's 0W30 or 0W20. The 0W20 was very quiet not too long after start-up. I've only used the 0W20 in winter though. The 0W30 works well in the summer, and the two oils are very close in terms of cSt at 40C. Before going thin, I tried going thicker (like 15W40 syn - and no, not in the winter). It had great cold numbers, with a pour point of down to -51F, but I guess it was too thick to keep them quiet until things got warm. Of course, once fully warmed up, the engine was silent on the thick stuff!
 
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like wise, i have tried all weights and types in my 8.1 big block. which has a rather loud slap at about 1200 rpm after its all warmed up. i did try some rotella 10-30 with a slightly noticeable quieting. same with the 10-30 hm mobil 1. but with the 5-30 mobil 1 it does about the same. so its up to you at this point. but for seattle the rotella 10-30 will be just fine it dont get that cold there.
 
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Best thing you can do is run a quality oil, correct weight, at reasonable intervals. The piston slap is a design issue, not an oil issue. Much research/discussion has taken place. The comforting thing is that it is in no way as bad as it might sound. Its irritating, but harmless. I know. I own a 2000 Silverado, 5.3. You'll be fine.
 
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 Originally Posted By: AzFireGuy79
My dad has a 2003 chevy silverado 1500 with the 5.3 . He has used Mobil 1 5W-30 since it was new with a wix filter. As many of you know this engine has the "piston slap" issue. I would like to stick with a synthetic if possible. The truck is at about 125,000 at present. He lives in seattle so it sees some cold weather but nothing too extreme. Your Opinions are appreciated!
In addition to piston slap GM engines of that era also suffered from carbon build up on the piston dome causing knock. You could try a can of GM top end cleaner to see if it helps too. Just another thought. Can't really recommend an oil that quiets the slap down. I had 2 5.3L's( 05 & 07 ). Those engines were past the time frame with the piston slap issue. Besides, the piston slap issue comes from too much clearance between piston and cylinder sleeve when the engine is cold. Until the engine warms up, causing everything to expand to a proper tolerance/clearance, the piston rattles and bangs around inside the cynliner. Oil isn't going to quiet that type of problem down.
 
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I have a 2005 Solverado with the 5.3 & it seems to like Pennzoil. I ran Valvoline SynPower in it right before Pennzoil YB & it seems to run "smoother" with Pennzoil.
 
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No, other motors had it. I think it was the biggest issue though in the 5.3L followed closely by the 6.0L. Oh, and I "think" 04 was the 1st year for the "FIX" that helped to stop the problem. 2000-2003 was the main problem era for it.
 
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I'm running Pennzoil Platinum in two 5.3's.... a 2000 and a 2004. I use 10w-30 in the 2000, which has 82,000 miles, and a slight amount of slap. It was a bit noisier with 5w-30, so I went with the 10w-30. I use 5w-30 in the 2004, which has 52,000 miles, and it hasn't shown any signs of slap.....yet.
 
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Pistons rock as they cross TDC where the thrust load from the rod angularity shifts from one side to the other. This makes noise. Harmless, but it is the source of piston slap in most all situations. Unfortunately, when the performance and fuel economy oriented pistons are run cold they are very prone to "slap" until they warm up to operating temperature. The piston designers and development engineers are always treading the fine line between piston slap cold and friction and power/fuel economy loss when the engine is warm.
 
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 Originally Posted By: xxch4osxx
Was the piston slap issue with the 5.3 motors only? My 2004 4.8 doesnt have any piston slap at startup or any other time. Just curious.
The affected V8 engines were mentioned in the thread already. As for V6 engines, I know it affected the 3.4L 3400 V6, and the 3.1L 3100 V6.
 
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 Originally Posted By: wannafbody
Can't go wrong with German Castrol 0W30
This is what I use in my 5.3L and have experienced noticeably less piston slap noise. Pennz Plat 10W-30 also does a good job of reducing slap noise. Mobil products were the worst for me, although I never tried 0W-40. I've experienced the noise in 5.3, 6.0, and 8.1L engines. Doesn't seem as noticeable in the 4.8's I've driven. Anyway, various "thick" 30W oils seem to help with this issue.
 
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The LSx motors actually do well on a thicker oil. I have thought about running M1 0W-40, but for now I run the green cap 0W-30. It's pretty quiet after 15 seconds of startup. I've got a Flowmaster catback, so any slap on startup gets drowned out.
 
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