CSK

knez · April 12, 2005

Well I guess I have it (csk)=2500hd 8.1L cc.At about 10k it started.At first it sounded to me like lifters pumping up and has slowly gotten worse from a slight tick to a knock only for the first 5 min to 10min of warm up over the last 6k miles.I just recently changed oil to mobil 1 10-30w synthetic from whatever dealer was using i believe it was just there normal 10 30w oil.Any way my question is what can I do to make this thing quieter?It seems louder now then before.If its warm and I turn it off for about 20mins or longer it will knock know for a few mins real embarassing.Love everything about truck runs great,love the power just cant stand the knocking noise. any help would be appreciated,if there is any .KNEZ

snoman · April 12, 2005

Well I guess I have it (csk)=2500hd 8.1L cc.At about 10k it started.At first it sounded to me like lifters pumping up and has slowly gotten worse from a slight tick to a knock only for the first 5 min to 10min of warm up over the last 6k miles.I just recently changed oil to mobil 1 10-30w synthetic from whatever dealer was using i believe it was just there normal 10 30w oil.Any way my question is what can I do to make this thing quieter?It seems louder now then before.If its warm and I turn it off for about 20mins or longer it will knock know for a few mins real embarassing.Love everything about truck runs great,love the power just cant stand the knocking noise. any help would be appreciated,if there is any .KNEZ

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GM has had for lifter tick issues that they say are normal because there are so many of them out there. If under warranty pressure dealer to fix the problem and if not you can replace the lifters yourself but you might even check to see if they are adjusted correctly to begin with.

GM-Tech · April 12, 2005

What year? Cold start knock typically doesn't last 5 or 10 minutes. And it certainly doesn't occur if shut off for a short time when warm. Haven't seen it in an 8.1 either. I suspect you have something different going on.

BTW, the lifters are not adjustable.

SS Crew · April 12, 2005

My truck makes that cold start knock sound only at start-up, I thought. While going through a drive-thru I could hear that ticking sound. It didn't sound like a lifter tick, or a rod knock, or even an exhaust leak. The truck runs like a champ so I'm reluctant to take it to the dealer. But I keep thinking maybe the engine is running it's best before it craps out. I hope not. Decisions, decisions.....

knez · April 12, 2005

What year? Cold start knock typically doesn't last 5 or 10 minutes. And it certainly doesn't occur if shut off for a short time when warm. Haven't seen it in an 8.1 either. I suspect you have something different going on.

BTW, the lifters are not adjustable.

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Its a 04.I may be exaggerating time but at least 5min and I let it warm till noise goes away then when i drive off if i let off gas it will make rattling/ticking noise to quote someone else on the board i heard before descibe it " it sounds like a box of marbles rattling around in there" it will do that for another few mins then go away unless it sits for over 20-30 mins then it will rattle for few mins but not like it does in morning in regards to letting off of gas noise it only does that in morning warm up. At first I thought lifters cause of it doing it when warm i figured oil bleeding down and lifters needing to pump up?I guess I should take it to dealer started to mention it to them but before I could finish he said "its normal they all do that".Thanks for the reply

snoman · April 13, 2005

But is it a rod knock, a piston rattle/slap or valve tick?

knez · April 13, 2005

But is it a rod knock, a piston rattle/slap or valve tick?

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I really don't think its a rod knock.Never thought of that thou.I just went out and started it.It sounds like a diesel for like 1 minute literally then quiets down to a quiet rattle then couple mins later it goes away completely but when i drive away after that if i let off gas rattles if i get back on gas goes away let off gas comes back and will do this for about a mile or so I would say thats why im thinkin csk(till pistons warm up enough?.At first when it started making noise it sounded like lifters pumping up but has graduated to this its really hard to describe.I appreciate your time.Knez

snoman · April 13, 2005

But is it a rod knock, a piston rattle/slap or valve tick?

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I really don't think its a rod knock.Never thought of that thou.I just went out and started it.It sounds like a diesel for like 1 minute literally then quiets down to a quiet rattle then couple mins later it goes away completely but when i drive away after that if i let off gas rattles if i get back on gas goes away let off gas comes back and will do this for about a mile or so I would say thats why im thinkin csk(till pistons warm up enough?.At first when it started making noise it sounded like lifters pumping up but has graduated to this its really hard to describe.I appreciate your time.Knez

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Sounds like piston slap. (piston rocking in over sized bores. GM made tens of thousands (maybe hundreds or thousands) engine with the piston improperly sized for the bores (or bore improperly sized for pistons) and they can rattle and knock until it heat up and the piston swells some with heat and enough to quiet it down. GM says it is normal or sticky rings to avoid massive recalls. The good news is that it is not fatal but it can be very annoying.

knez · April 13, 2005

So basically the only way to make it quieter is change pistons?Which I wouldn't do. What about heavier oil weight like 10-40.Anything to maybe quiet it down a little.Its just so d**n embarrasing to have a 40 thousand dollar truck that sounds like a 1500 beater on start up.Thanks for the replys Knez

snoman · April 13, 2005

So basically the only way to make it quieter is change pistons?Which I wouldn't do. What about heavier oil weight like 10-40.Anything to maybe quiet it down a little.Its just so d**n embarrasing to have a 40 thousand dollar truck that sounds like a 1500 beater on start up.Thanks for the replys Knez

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Heavier oil will not really help and can add problems of its own from increased drag with reduced MPG and the increased possiblity of piston rings becoming gummed up or stuck over time. It sucks no question about it. Your best bet is to try to pressure GM for a fix. It will never get better and will slowy get worse over time. The sad part is is that GM used to build some really quiet engines before they switched to the new modular engines with a the NBS models and then started have all kinds of piston slap problems from poor quality control. Their officail position last I heard was "sticky" rings from improper oil and maintainance as a cop out. Sorry that I cannot be of more help.

Scyry · April 14, 2005

10 30w help my 6.0 with the CSK too. My truck sounds similar to yours, but mine didn't get really bad until about 30k and GM would do nothing for me. If you pressure/complain enough, they will give you 100k warranty on it.

Mine does the same thing, really knocks for the first 5+ minutes of warm up then quiets down. Mine always has a "rattle" to it though, no matter what when it is idling. The dealer tells me it is "the loudest case of CSK they have had, but it definately is CSK." Even though if it sits for 30-45 minutes it will knock when I first start it. As for the carbon build up excuse they give, I run Shell gas, 85 octane. If the grade of gas is the problem they should say run mid or premium...not low grade as they do. Oh well, there is my 2 cents on the subject, people around here are probably tired of me chiming in about CSK.

firstruck · April 29, 2005

hey knes, if it'll make you feel any better I have all those noises (i may even have been the "box of marbles" guy you refered to. Anywho I've got 105,xxx miles and she still runs strong, so yea it's a little annoying but what the hay it gets me where I need to go

Mighty HD · April 30, 2005

Mine just started doing it too...a knock on the driver side....it's on the lower end....and it's not CSK. I'm gonna drive it till it throws a rod...F**k it .....I paid good money, if it blows up I'll expect a new motor.