Thread: The little engine went knock, knock, knock

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OK, so I come back from vacation, I start up the o'l monte, take it for a spin then I start hearing this wonderful tapping noise, I felt sick, cause it didn't sound like something simple like and exhaust leak, I would have even been happy if it was a lifter, but, no, that would be too easy, so I checked it out it seems to be coming from the bottom end, but it's not as loud as a main bearing would be, i'm thinking that it might be a rod bearing, because it is distinctively coming from eaither the # 2 or #4 cylinder but I guess I won't know till i drop the pan, I hope it's an easy fix.

Have you guys had anything like that happen before? it just started doing that all of the sudden, I wasn't racing it or anything like that, it just started under normal driving conditions, I alway check on the oil to make sure that it is ok, any thoughts?????????

I never have reved this engine over 5000 and it's only two years old and has only 20,000 miles on it, am I screwed?

This may not be what you are experiencing but my truck was tapping and I thought oh crap. Turns out it was the mech fuel pump rod tapping.

that would be great but I have an electric fuel pump, unfortuneity

I wish I could be that lucky

Pull the plug to #2, then #4. If it stops tapping, its the rod bearing to the cylinder thats unplugged, so to speak

but won't it still tap because the crank is still rotating? evevn though that cylinder is not firing?

I figured that would be the case. But its worth saying.

No. the cylinder wont have the pressure from the the expanding gasses. As such, it shouldnt knock unless your bearing is really, really smoked. From the sound of it, it isnt.

Originally posted by drg84
No. the cylinder wont have the pressure from the the expanding gasses. As such, it shouldnt knock unless your bearing is really, really smoked. From the sound of it, it isnt.

drag, thats some old school stuff there, way to go.

Originally posted by Monte Man
but won't it still tap because the crank is still rotating? evevn though that cylinder is not firing?

I would get onto it quick, or soon its going to go bang ?

Oh yeah I forgot whats your oil pressure like ? If you dont have aguage in the car, just fit one of those dirrect reading mechanics oil pressure guages where the electric oil sender is. I would go with pulling the plug wires on those cylinders untill the knock dissapears and checking your oil pressure as confirmation. Your oil pressure should read 50 to 60 PSI with astock bottom end. And if/when you pull the motor down replace the oil pump. hope this helps some. S

Good idea Southernor. Always better safe than sorry. Also, if you find what cylinder it is, check the rods themselves. Many times a loose rod will cause chipping/scouring on the bottom end. If the rods look good, check the clearances on the other bearings. There is nothing worse than having to tear down your motor for crank bearings after replacing the Rod bearings.

Cross your fingers and check to see if your flywheel or torque converter bolts are loose, hope it's something small like that.