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3100 Valve Clatter


Mark 97 Cutlass Coupe

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Hey guys, I have a 97 Cutlass coupe with 140,000 miles and the 3100 motor. For the first 5-6 minutes after startup (only after sitting all night, or maybe 6 hours) there is a lot of valve clatter. Like I said, after 5-6 minutes it goes away, and is then quiet. Even when it clatters it runs very smooth, and once that noise is gone the motor is absolutely silent. I am running the reccomended 5-w 30 (as stated on the motor). Is this just what these motors do, or am I looking at a problem? Thanks.

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Yeah my 3100 has done it for a few years now. Ive been told a variety of things it could be, lifters valves etc. Havent had any problems, but its definately made me wonder about the health of my motor.

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Sounds like lifters could be gummed up. I'd say run a can of seafoam in your crank case for about 50 miles before you change your oil, and see if it improves anything.

 

What kind of oil filter are you using?

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  • 1 month later...

My Cutlass only has 66K miles on it and it does it... it's almost as if the oil runs off the lifters after it sits and when you go to run it again it clanks. I have had 2 W body Cutlass', and both did the same thing. Never caused a problem. I drove my other 95 Cutlass for a year and a half with that happening every morning I would start it up and it never lead to internal engine damage. Just something about the 60 degree V6 I guess:shrug:

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Welcome to owning a 3100. Mine has been doing this as long as I've owned it (almost 2 years now), including on some VERY cold days where it tends to last a bit longer. Never had a problem.

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I don't know if anyone else does this but I like to be extra cautious about the situation. I normally let the car run (warm or cold outside) until the tapping goes away. Not sure if it is necessarily needed... but I like to baby it :lol:

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I don't know if anyone else does this but I like to be extra cautious about the situation. I normally let the car run (warm or cold outside) until the tapping goes away. Not sure if it is necessarily needed... but I like to baby it :lol:

 

Yeah you should never just start it and go, especially when it does that. Letting it sit too long isn't always good either.

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Even my 3400 does this a little bit. But the 3100 that was in my car was horrible! But when I tore it down and looked at everything, there was no signs of damage at all. So its basically harmless noise.

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someone was running a turbo 3100 for a while.... when they everntually replaced it, the pistons seem to have shrunk 1/8" in the bore, and it still ran. :lol:

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I don't know if anyone else does this but I like to be extra cautious about the situation. I normally let the car run (warm or cold outside) until the tapping goes away. Not sure if it is necessarily needed... but I like to baby it :lol:

 

I do the same thing! On a cold winter day in Pittsburgh it might rattle for 5 minutes or so until it quits. Has anyone ever switched to synthetic oil to see if it stops? A friend of my brother's is a mechanic, and he says it should stop it. He also said that the 3100 was known for being noisy when cold, and that the motor should last 200,000 plus miles with proper care.

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these engines are known for that, along with the 3.4's..my aurora was known for piston slap, after 5 mins it went away..its normal, but as someone said, run either seafoam or the GM engine cleaner in the oil before your oil change, run it for a few miles before changing it so it can work

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these engines are known for that, along with the 3.4's..my aurora was known for piston slap, after 5 mins it went away..its normal, but as someone said, run either seafoam or the GM engine cleaner in the oil before your oil change, run it for a few miles before changing it so it can work

 

What is seafoam?? And has anyone used synthetic oil in a 3100 and had the noise go away?

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What is seafoam?? And has anyone used synthetic oil in a 3100 and had the noise go away?

 

Seafoam cleans your engine and injectors, you let it suck in the engine and it creates huge clouds of white smoke (it's awesome I have seen it done) :thumbsup:

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I run synth in my L82 and I still get the noise. It will not go away.

 

Although someone mentioned a mix of 10w30 and 5w30 making it quieter/ not last as long.

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When I worked at Chevy a couple years ago we had a few corvettes with the same issue. GM had a bulletin on this for the vette's and for pretty much all of there engines. Its something to do with the coating on the skirts of the pistons wearing off and the increase in the gap between the piston and cylinder walls cause the noise on startup and cold idle. Im gonna see if I can find it somewhere. I know that when GM crashed some of these little bulletins seemed to disapear into thin air I think to protect themselves or something.

 

-Jarek

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i can pull them via alldata, but yes, i believe it was a tin coating on the pistons? from the factory, it was only applied to one side or something like that, the replacement parts have it all the way around.

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It wasn't just vettes, but anything an LS engine. Pretty damn annoying but it doesn't hurt anything.

 

Ditto on the 3100/3400. My brother's 3100 GP he just bought with only 80,000 miles on it already clatters.

Edited by jman093
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