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6.2L Rebuild Questions

12K views 22 replies 6 participants last post by  Mymaggiebell 
#1 ·
Hey guys - so I've posted in a couple of the "cold knock" threads, understanding that its not entirely uncommon for the 6.2's to have a knock to them when cold. I havent owned it in warm weather yet, so I've not really got a chance to monkey with it much when its above 50. Going to change oil/filter soon to see if it helps, but, in the meantime my mind has been wandering.

My 09 has 105k on the ticker (just got it last month), and it definitely has the knock - before I read about the piston slap I thought it was definitely a more terminal issue like a rod, main bearing, etc. Now, I am not so worried, but it got me to thinking:

If in fact this thing goes south and has some internal catastrophic damage - what rebuild/replacement options are there? Short of buying a complete setup, are there any places out there selling 6200 Short Blocks? Anyone had luck with boring out the cylinders .030 and going with new pistons/rings?

No idea if I'll ever need it, just kinda kicking the tires on ideas to have in my back pocket if this ever turns into more than just a piston slap/knock issue.

Thanks!
 
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#2 ·
your signature says you are running the 87 octane tune. running lower octane fuel is known to cause knock in the 6.2 - it even states it in the owners manual, and you know they hate saying the trucks will do any wrong.

try installing the diablo tune and running 91 or higher octane for a few tanks and see if it settles down.
 
#3 ·
^^^This...I'd be running at least 91 in that engine regardless of what octane tune can be put into it.
 
#4 ·
Thanks guys - I run 91 in it, have for a few tanks, and I've tried all the different tunes, no change. This definitely sounds deeper than spark knock or pre-ignition. This is bordering on rod bearing or something internal, but it does go away (or at least get better) as the temp comes up.
 
#5 ·
My 6.2 has a distinct cold tick, my 5.3 did as well. Was never a knock but loud tick; I have been running 93 octane in the 6.2 all along with tick. The tick is quite deep but no knock I don't believe. Good luck finding out the issue.
 
#6 ·
just had a new cam and lifter job done. my truck had worn/scored lobes and collapsed lifters on cylinder 4 and 7. used full synthetic oil and run 91-94 octane with a blackbear tune. 90 k on the clock. unacceptable but it was covered under warranty, so shouldn't be complaining. oh yes, also found a head gasket leak and two lines done (trans cooler and oil cooler). if u have warranty make them investigate it!!!
 
#7 ·
Mymaggiebell - what were the symptoms that lead you to determine it was worn cam and collapsed lifters?
 
#8 ·
I was noticing what turned out to be correct, lifter noise. I was familiar with it from old truck. the biggest thing however, was the cold start, and idle. when I started it for the service manager, he agreed that it sounded awful. a few times too, we'll after it warmed up it was having a rougher time accelerating. most people probably would have not noticed it, but I am more "anal"!
 
#9 ·
I hate to ask but can you describe the cold start sound, my 6.2L has developed a terrible sound when cold until almost to operating temp...like a "ta ta ta" that follows the rpms. Very noticeable inside the cab.

I took a video of the sound, maybe out can here it over the exhaust...800-2500 rpm Cold start, you can hear it at 6-7 sec mark.

https://www.youtube.com/watch?v=CRtCieI ... e=youtu.be

Thanks,
Mike
 
#10 ·
My tick is light when idling cold, but if not operating temp and I attempt to accelerate there is an audible tick for 5-20 seconds. After that it's gone until another cold start. Thought this was relatively common on these trucks.
 
#12 ·
devilray427 - thats the same knock I have. Seems to be coming from the passenger side, and "seems" to get better as the engine warms up, but its still noticeable. Mine has 105k on it now, going to try an oil/filter change to see if it has any impact (doubtful).

My fear is that it is internal like the cam/lifter issues we're talking about. Please let me know if you come up with anything on yours!
 
#13 ·
Here is a good audible video that has audio from piston slap - this is not my video; but is easier to hear than yours. The video you have sounds similar but at higher RPMs; is yours a similar sound? If so it is a common sound pre-engine warm up.
 
#14 ·
Did you mean to attach a link to your piston slap video? Interested to hear what a true example of that sounds like before I jump off the cliff for a top end rebuild.

I found this one on pistonslap.com - seems pretty close - http://www.pistonslap.com/photos.htm
 
#16 ·
Yeah, that sounds like "multiple" things clanging around during the rotation of the engine. Mine sounds more like a single "knock, knock, knock" that is in sync with the crankshaft RPM's.

Unless I tell myself I just have 1 piston slapping...haha.

Either way, I'll probably nurse it until it gets worse, then make the call as to how far down I tear into it and start replacing pieces.

Thanks for the Video Evidence!
 
#18 ·
sadly I do not - I bought it with over 100k, and didn't notice it at first, curious if the dealer I got it from may have put a can of Rislone or something in it to make it quiet enough to sell. Not sure, not anybody's fault but mine in the end, so I'll work through it.
 
#20 ·
After this thread I'll take her in and see what they say, I have had tech's listen to it before, but warm and they can never hear anything.....I'll have to schedule to leave my daily driver overnight..
 
#21 ·
scheduled to leave my truck overnight at our dealer tomorrow to see if they can diagnose the problem. Honestly I really hope they do not have to crack the seal on this 6.2. I'll try to post updates.
 
#22 ·
Update: Day 1...dealer called and said they could not hear anything...so the morning of day 2 I drove back to the dealer and recreated the noise myself. The technician acknowledged the noise and said it was "borderline normal" valve train noise. The service manager said now there is a paper trail so if I have any more issues to bring it back...so I guess we wait and see.
Mike
 
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