Chevy engine knock when cold and under load

[ERIC87442]

so, got an issue with my daily driver. its a 95 2 door Tahoe, its got a Chevy 350 in it, in the morning when its cold i got an engine knock only under a load though. it will last until the engine is about a quarter of the way warmed up or so. then it runs great, its got great oil pressure. and drives just fine. just annoying as all hell. its got 188k on the body unknown mileage on the engine haha, i know its not the original engine. supposedly it only has like 5k on the engine or so any ideas anyone? i would ask on another forum but this is the only forum people really answer my questions and actually know what they are talking about :lol: sorry for the non g-body related questions lately!

 

[clsmith1424]

my dads 2000 gmc did the same thing. GM said that it was a lifter and was nothing to be concernd with.

 

[1badbu]

With that kind of mileage it could be simply as cylinder wearing loose.It takes a little heat to swell up the pistons and on a loose race motor you will even get that knock or piston rattle until it swells the pistons enough to make the rings tighter against the cylinder walls.
Or it could be a number of issues that you'll never figure out until the motor is torn down.
Cam bearings wil wear so bad it can let the camshaft actually move around.A buddy of mine had a small block dodge do this and like to never got the cam bearings out.
A rist pin (connects the piston to the rod) usually makes a rattle,but a higher pitched noise than a piston or bearing noise.

But at that kind of mileage on the motor it needs an overhaul.Because it will most likely just get worse,or worse lock up.

 

[79elky454ss]

is it a vortec engine? is it using coolant?

 

[ERIC87442]

i really dont know the mileage on the motor, its not the original one i know that for sure, it supposedly has only 5k or so on it. it doesnt seem to use any oil so i dont think its that high mileage of an engine, its not a vortec engine and not its not using coolant

 

[79elky454ss]

when you say knock, do you mean a heavy, metallic, lower end knock?

 

[79elky454ss]

when you say knock, do you mean a heavy, metallic, lower end knock?

I ask because a knocking rod usually gets worse with temp not better

 

[ERIC87442]

i guess it kinda sounds like a clattering noise

 

[SScamino]

With that kind of mileage it could be simply as cylinder wearing loose.It takes a little heat to swell up the pistons and on a loose race motor you will even get that knock or piston rattle until it swells the pistons enough to make the rings tighter against the cylinder walls.
Or it could be a number of issues that you'll never figure out until the motor is torn down.
Cam bearings wil wear so bad it can let the camshaft actually move around.A buddy of mine had a small block dodge do this and like to never got the cam bearings out.
A rist pin (connects the piston to the rod) usually makes a rattle,but a higher pitched noise than a piston or bearing noise.

But at that kind of mileage on the motor it needs an overhaul.Because it will most likely just get worse,or worse lock up.

What he said, it sounds like a piston knock. and with it getting colder outside you can deffintly tell and then when summer comes around you won't here it (well that much)

 

[ERIC87442]

so should i just not care?