Ls1 tick on startup
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Joined: Apr 2019
Posts: 82
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From: Ohio
Ls1 tick on startup
I know there are a lot of threads about this issue already, I am just paranoid! I just bought an 02' corvette with 25,000 miles in October and noticed especially on cold mornings, about 30 seconds after startup a very noticeable engine tick starts. It'll go away if you bring it up to 1300 rpm or so but once back at idle it'll start again until it's roughly warmed up.
I'm thinking its piston slap but want to make sure before putting too many more miles on it.
things to consider:
it has been tuned in the past, has what im thinking is either a 160 or 180 thermostat in it, fans kick on around 195 or so. Coolant Stays consistent at temps around 187-195.
oil temp is 180 at the lowest once warmed up
oil pressure is about 35psi at idle warm, 45psi cold.
I let it warm up at least to 140 and don't get hard on it until oil and coolant is up to temp
by "get on it hard" I like to do some 1st-4th gear pulls, 4500-5000rpm shifts, rarely take it to redline
I did an oil change first day i bought it, pennzoil 5w-30 with acdelco filter.
I'm thinking its piston slap but want to make sure before putting too many more miles on it.
things to consider:
it has been tuned in the past, has what im thinking is either a 160 or 180 thermostat in it, fans kick on around 195 or so. Coolant Stays consistent at temps around 187-195.
oil temp is 180 at the lowest once warmed up
oil pressure is about 35psi at idle warm, 45psi cold.
I let it warm up at least to 140 and don't get hard on it until oil and coolant is up to temp
by "get on it hard" I like to do some 1st-4th gear pulls, 4500-5000rpm shifts, rarely take it to redline
I did an oil change first day i bought it, pennzoil 5w-30 with acdelco filter.
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Well i think what your reconizing as a noise but it most likely as a "Piston Slap" I have in my NTM 2003 LS1 convertible and my last C5 coupe and even on my 07 convertible with a LS2 It goes away by the time I get to the corner street where I live. My current 03 has 11296 miles and when I bought my C6 with the LS2, it too had the very same issue. It is gone by the time the engine get to 100 degrees or so. Not to worry !
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From: Ohio
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Sorry to tell you this, but you have to start digging in to that engine. I would start by pulling of the valve covers. To me, that's not a rod knock.
From what people posted about piston slap, it goes away pretty fast.
From what people posted about piston slap, it goes away pretty fast.
Last edited by Vetteman Jack; Dec 21, 2024 at 09:18 PM.
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Best to take the vehicle to a dealer or a trusted independent shop and have them properly diagnose the noise. Good luck - hope it is not something major that requires engine work.
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Thread Starter
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Joined: Apr 2019
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From: Ohio
will probably dig into it once i get engine project on my 69' finished up.
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My 2K with 129,000 on it has definite piston slap when cold started, lasts about a minute. What I hear is not piston slap, I agree it sounds valvetrain related.
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My '01, with 32,000 miles on it, has the "piston slap", when first cold. Mine, too, lasts about a minute, or so. However, on second thought, I do hear a slight "lifter tick" on my car, at idle. But if I bring the engine up 50-75 RPM over idle, it goes away, and the engine is as quiet as can be.
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My 02 with 41K and has had the the same tic for a while. Goes away in a couple minutes when warm, I took her into my dealer and explained the issue, of course it wasn't doing it when I arrived, he stated it is a pretty common issue and if it goes away when warn he wouldn't mess with it. But if I wanted, he'd "dig into it". Yeah, at that shop prices, I'll deal with the tic upon start-up.
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I wish my lifters were ever that quiet…. Still, that doesn’t sound like all the lifters rattling, but like one, or pistons slap, or an exhaust leak.
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Maybe check the spark plugs. When I inherited mine it had another "tick" besides the piston slap that would only last about 20 seconds. Turned out # 3 spark plug was loose, when I changed the plugs I discovered it.