1993 Saturn SL2 Crank Knocking

NPIKE2010

MEMBER
1993 SATURN SL2
4 CYL
2WD
AUTOMATIC
181,000 MILES

ABOUT TWO DAYS AGO MY CAR RAN LOW ON OIL THE OIL LIGHT CAME ON THEN THE COMPUTER SHUT IT OFF. SO I TOWED IT HOME AND TOPPED THE OIL OFF. THEN IT STARTED KNOCKING. WE DIAGNOSED IT AS A ROD BEARING. SO I REPLACED ALL FOUR BEARING. CYL 2 ROD BEARING WAS BAD AS WE THOUGHT. THE CRANK WAS NOT HARMED BEARING WAS STILL THERE AND DIDNT TURN JUST ABOUT THERE THOUGH. NOW AFTER ALL THAT. I STARTED THE CAR AFTER REPLACING THE BEARING KNOCKING CAME BACK AGAIN AND ITS FROM THE CRANK BECAUSE IT GETS LOUDER WITH HIGHER RPM'S.

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SATURNTECH9

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30,869 POSTS

A rod knock will get louder at higher rpms too. Take off the plug wires one at a time and see if the knock goes away when you remove one of the wire's.

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Thursday, July 15th, 2010 AT 9:54 PM

NPIKE2010

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OK I JUST TRIED IT AND IT SEEMED LIKE IT WENT AWAY. BUT HARD TO TELL SINCE THE ENGINE BOGGED DOWN FROM THE LOSS OF THE CYL. SO IF IT'S THE ROD CAN I REPLACE THAT FROM UNDER THE BLOCK THROUGH THE OIL PAN. LIKE THE BEARINGS. AND WHEN IT BLEW THE BEARING ON THAT CYL THE BEARING WAS REALLY BAD IT BASICALLY WELDED ITSELF TO THE ROD.

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Thursday, July 15th, 2010 AT 10:15 PM

SATURNTECH9

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If it welded itself to the rod then there is a good chance you have a bad rod. If you have to replace the rod you will have to remove the head it won't come out the bottom.

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Friday, July 16th, 2010 AT 2:56 PM

NPIKE2010

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Ok so unbolt it from under the oil pan and push up through the head? Is there anything particular I should also do while replacing the rod.

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Friday, July 16th, 2010 AT 5:34 PM

SATURNTECH9

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Yes the rod pushes up threw where the head was.I would make sure the crank surface is nice and smooth measure the crank where the rod goes make sure it's not under sized or ob longed meaning it's round. And when you replace the new rod and rod bearing make sure you use some plastic gauge. It's a piece of plastic that will check the clearance of the rod bearing on the crank. Did you check all of the other rod bearing's for damage?Also I would check the timing chain for wear/looseness. You have a lot of miles on the car and it's using a lot of oil if it ran low and spun the rod bearing. Unless you went too long on your oil change. Are sure you just want to patch this car up?Might be time to start looking for a different car?