bluegp Posted August 25, 2003 Report Share Posted August 25, 2003 Recent posts about ticking (injectors) prompted me to ask about the noise mine makes. It's a "knocking" sound (not detonation) that occurs when the engine is first started and let to idle. It's louder when the engine is cold. It will increase with rpm up to a point then will go away (will come back as engine goes back to idle). It will go away once the car is driven. It has done this ever since I've had the car (about 50k miles ago). I've heard lots of other ones (2.8/3.1 cars) do it too. Does anybody know what I'm talking about? Quote Link to comment Share on other sites More sharing options...
mdelorie Posted August 25, 2003 Report Share Posted August 25, 2003 I've heard some people blame piston slap as the culprit... but I think that was move with 3100s Quote Link to comment Share on other sites More sharing options...
PaPaPooh Posted August 25, 2003 Report Share Posted August 25, 2003 sounds like a rod knocking to me Quote Link to comment Share on other sites More sharing options...
Marcus18 Posted August 25, 2003 Report Share Posted August 25, 2003 I have the same noise. I always figured it was one of these. Engine noise: A tick or rattle when the engine is started cold may be due to too much wrist-pin-to-piston clearance. (1994-95) Engine noise: A rattling noise from the engine when the car is started after sitting is often caused by automatic-transmission pump starvation or a sticking pressure-regulator valve. (1991-95) (these are from Consumer Guide® used car review 1990-96 Pontiac Grand Prix ) then again I'm a 90 so I may be outta luck. marcus Quote Link to comment Share on other sites More sharing options...
GPRACER Posted August 25, 2003 Report Share Posted August 25, 2003 It's piston slap, do a search, this topic has been beat to death here.. Quote Link to comment Share on other sites More sharing options...
bluegp Posted August 27, 2003 Author Report Share Posted August 27, 2003 It's piston slap, do a search, this topic has been beat to death here.. Thanks, I'll check it out. That's what I figured it was. I have heard something about the transmission pump making noise before, but I'm not sure what that would sound like. Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted August 27, 2003 Report Share Posted August 27, 2003 It's piston slap, do a search, this topic has been beat to death here.. better hope so....but if it is a rod knock at least finding another 3.1 is easy and swapping the engine is pretty easy too. i had a different rebuilt 3.1 in my Cutlass for a month and it started knocking within 100 miles. by 500 miles i was scared to drive it....it was extremely loud and would get worse as RPM went up. then i put my original 3.1 back in and it's still running great @ 211,000 miles (never rebuilt). i bought the rebuilt engine with the Getrag 282 i swapped in for $900, and now the trans is poop. oh well life sucks. at least i can find another 282 for around $300 (used) and can probably have it swapped in within a weekend after all of my previous experience....which i sort of appreciate since i learned ALOT about my car and am not afraid to work on it myself anymore. i can pretty much do anything to it (and have) except rebuild the motor or trans. joshua Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted August 27, 2003 Report Share Posted August 27, 2003 I dont think it piston slap, not on a 3.1L. Anyway, you said its done this ever since you got it and have not experience any adverse affects, right? Then dont worry about it. If it works, dont try and fix it. Thats my advice. If you notice it causing a problem, then look into it Robby Quote Link to comment Share on other sites More sharing options...
bluegp Posted August 27, 2003 Author Report Share Posted August 27, 2003 Like I said, I've driven it at least 50,000 miles and the noise has been the same - If it was a rod knock, I think the engine would have self-destructed a long time ago. Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted August 27, 2003 Report Share Posted August 27, 2003 Like I said, I've driven it at least 50,000 miles and the noise has been the same - If it was a rod knock, I think the engine would have self-destructed a long time ago. I agree. Just drive it hard as hell, then if it blows, you got a reason for a motor swap Robby Quote Link to comment Share on other sites More sharing options...
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