knocking from engine area bearing?
Thread Starter
Heel & Toe
Joined: Mar 2010
Posts: 19
Likes: 0
knocking from engine area bearing?
I think I've been had.. Purchased this 1987 with only 67,700 miles
I've put about 250 miles on it since the purchase parked the car
this afternoon and about 4 hours later I start it and all hell breaks
loose, knocking noise from engine area, oil pressure 40 psi and higher
when gased, also have a scraping noise I'm thinking bearing or flywheel
or maybe a push rod but oil pressure is good so not sure where to
start any ideals.
Dyno Jim
I've put about 250 miles on it since the purchase parked the car
this afternoon and about 4 hours later I start it and all hell breaks
loose, knocking noise from engine area, oil pressure 40 psi and higher
when gased, also have a scraping noise I'm thinking bearing or flywheel
or maybe a push rod but oil pressure is good so not sure where to
start any ideals.
Dyno Jim
Race Director
Joined: Dec 2006
Posts: 10,383
Likes: 4
Get a mechanic's stethoscope and pinpoint the source of the noises.
Verify all vacuum lines and EGR.
Check spark at each plug.
OHM out each injector. Listen to each injector with the stethoscope. They should all sound about the same.
Test fuel pressure.
See if the spark plugs fit any symptom on the diagnostic charts.
Verify all vacuum lines and EGR.
Check spark at each plug.
OHM out each injector. Listen to each injector with the stethoscope. They should all sound about the same.
Test fuel pressure.
See if the spark plugs fit any symptom on the diagnostic charts.
Le Mans Master
Joined: Dec 2006
Posts: 5,139
Likes: 482
From: H-Town Texas
Spun bearings make a very distinctive sound, and oil pressure is not always the tell tale sign. Don't ask me how I know this.
First check pull your dipstick and check for metal flakes in the oil. If you want really check the oil do a change. Drain the oil through a cloth to catch any particles, and cut the filter open.
Another thing to check would be to see if there is oil in the coolant by checking the overflow resevoir. Also pull the oil fill cap and make sure that it looks like oil and not chocolate milk. A bad head gasket would cause this.
Things like exhaust manifold gaskets gone bad, vaccum leaks, belts can cause a small block chevy to sound like it's falling apart too.
I'm not positive, but it seems odd that a bearing would spin while sitting engine off. I think they tend to do this while they're running, but I guess it could happen on start up if it was on it's way there.
Of course you could just drop the oil pan and get a first hand look.
First check pull your dipstick and check for metal flakes in the oil. If you want really check the oil do a change. Drain the oil through a cloth to catch any particles, and cut the filter open.
Another thing to check would be to see if there is oil in the coolant by checking the overflow resevoir. Also pull the oil fill cap and make sure that it looks like oil and not chocolate milk. A bad head gasket would cause this.
Things like exhaust manifold gaskets gone bad, vaccum leaks, belts can cause a small block chevy to sound like it's falling apart too.
I'm not positive, but it seems odd that a bearing would spin while sitting engine off. I think they tend to do this while they're running, but I guess it could happen on start up if it was on it's way there.
Of course you could just drop the oil pan and get a first hand look.
Safety Car
Joined: Nov 2008
Posts: 4,328
Likes: 15
From: Jacksonville FL
I had a bolt come loose on the flywheel and it made a sound like the engine had spun a bearing. Pop the inspection cover and have a look. Something may fall out. Scraping could be something loose inside the bell housing as well.
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
I had a piece of carbon break off of a valve on a Z28 one time and lodge on the top of a piston. it sounded like a rod knock. GM sells an upper cylinder solvent that is ok to add to a running engine that melts the carbon.
Give it a try.........although if you have other noises,I would remove the rocker covers, and investigate there. I had a pushrod screw itself through a rocker on my pickup, and the rocker just kept banging away till I got home.
With all the noise, I thought I had eaten an engine, I got it home and let it sit. when I started taking it apart to change the engine, I found the rocker. changed the rocker and pushrod, adjusted the valves, I got another 35,000 miles out of it before it started smoking.
Give it a try.........although if you have other noises,I would remove the rocker covers, and investigate there. I had a pushrod screw itself through a rocker on my pickup, and the rocker just kept banging away till I got home.
With all the noise, I thought I had eaten an engine, I got it home and let it sit. when I started taking it apart to change the engine, I found the rocker. changed the rocker and pushrod, adjusted the valves, I got another 35,000 miles out of it before it started smoking.
Last edited by coupeguy2001; May 29, 2010 at 10:19 AM.
Thread Starter
Heel & Toe
Joined: Mar 2010
Posts: 19
Likes: 0
I think I've been had.. Purchased this 1987 with only 67,700 miles
I've put about 250 miles on it since the purchase parked the car
this afternoon and about 4 hours later I start it and all hell breaks
loose, knocking noise from engine area, oil pressure 40 psi and higher
when gased, also have a scraping noise I'm thinking bearing or flywheel
or maybe a push rod but oil pressure is good so not sure where to
start any ideals.
Dyno Jim
I've put about 250 miles on it since the purchase parked the car
this afternoon and about 4 hours later I start it and all hell breaks
loose, knocking noise from engine area, oil pressure 40 psi and higher
when gased, also have a scraping noise I'm thinking bearing or flywheel
or maybe a push rod but oil pressure is good so not sure where to
start any ideals.
Dyno Jim
I had a piece of carbon break off of a valve on a Z28 one time and lodge on the top of a piston. it sounded like a rod knock. GM sells an upper cylinder solvent that is ok to add to a running engine that melts the carbon.
Give it a try.........although if you have other noises,I would remove the rocker covers, and investigate there. I had a pushrod screw itself through a rocker on my pickup, and the rocker just kept banging away till I got home.
With all the noise, I thought I had eaten an engine, I got it home and let it sit. when I started taking it apart to change the engine, I found the rocker. changed the rocker and pushrod, adjusted the valves, I got another 35,000 miles out of it before it started smoking.
Give it a try.........although if you have other noises,I would remove the rocker covers, and investigate there. I had a pushrod screw itself through a rocker on my pickup, and the rocker just kept banging away till I got home.
With all the noise, I thought I had eaten an engine, I got it home and let it sit. when I started taking it apart to change the engine, I found the rocker. changed the rocker and pushrod, adjusted the valves, I got another 35,000 miles out of it before it started smoking.
flexplate and I see no cracks or anything that looks bad. I have pulled the
rocker box on the left side and see no problems no noise on the right side
so I did not pull. Carbon maybe I'll try spraying water into the TPI tommorrw I have noticed a scraping sound also, piston ring maybe? I'm
just trying everything before pulling the motor out..
Dyno Jim
Race Director
Joined: Apr 2003
Posts: 17,699
Likes: 1,667
From: moraga ca
As mentioned before, drain the oil and cut open the filter. If there is a lot of metal, start pulling the motor. Hopefully there will be a very small amount which is normal. Breathe easier and look look at the topend or the flywheel on back.
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