No oil to the top end of a V6 3400 engine
I have a 2001 Grand Am Gt with a V6 3400 motor. It just started knocking and I took to a mechanic. He said a back lift is making that noise because there is no oil getting to the top end of the motor. He went and changed the oil and found a pin in the oil from the engine. He keeps describing it as it like a pin from a U-joint. Any ideas what this pin is from and why there is no oil to the top of the motor.
Check with the 3400 owners over at GAOwnersClub.com - many of them have taken the motors apart when sealing the lower intake manifold leaks that plague the V6.
This is the best info that I can find. Here is the pump and drive system for a 3100 which is the same as your 3400. http://www.tonkinonlineparts.com/showAssembly.aspx?ukey_assembly=820183 Is the bottom end getting oil? Low pressure on the gauge or the low oil pressure light on. If your pressure is to low it may feed the bottom but not the top end (head pressure and friction losses) How big is the pin. Looks like there is a few small parts on the oil pump. Would cause low to no oil pressure. There is a roll pin driving the top of the pumps drive shaft, would cause complete failure. You could get the pin and compare the size to a new pump. Thats where I would look. If you can't find where is comes from?
He says the oil pressure is 40 psi. The pin I believe we've figured to come from the needle bearing of the colapsed lifter. The pin is half inch long and as thin as a pencil led. I am guessing that lack of oil to the lifter caused the lifter to go bad. The way the oil gets to that part of the engine is through the camshaft bearing, correct?
That's a fairly high oil pressure to have an oiling issue. Maybe there is a blockage somewhere. The oil runs through the block, it lubes the cam shaft bearings and supplies each lifter separately from the side. The oil then travels through the lifter and up the hollow pushrod to the rockers and valvetrain. Here is a pic of a hydraulic lifter. Might have to search around for somone with the same issue, see if they have an easy fix,if not might have to disassemble the topend.
I just talked to another mechanic and he suggested replacing all the lifters since we are in there and put a quart of trans fluit in with the oil. Must believe it is a clog and not a spun cam bearing. In a V6 engine, does the oil go through 1 camshaft bearing to 2 sets of lifters (2 of the 6 cyclinders?
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