: Can this be possible?

08-13-08, 05:05 PM
Hi all!

New here :)

I just bought a 1994 Seville STS yesterday. It has 66000 miles on it. It is in GREAT shape!

Now for the bad. There is a knocking (steady but varies it volume)that also klacks but not all the time. The knock gets lower/deeper sounding under load. I am guessing con rod. :(
Is this rare for a low milage N*?
Can the oilpan be dropped without engine removal? How bout the crank?

Great site!

08-13-08, 05:29 PM
no to both questions

08-13-08, 06:03 PM
Yes to the first question - no to the 2nd and 3rd

08-13-08, 06:10 PM
I have pulled the serp belt with no change in the noise. Any chance it could be valve train? Sounds pretty loud. I will record the sound and post it.

08-13-08, 07:11 PM
Here i a video of the knocking...


08-13-08, 08:22 PM
motor is gonzo....

08-13-08, 08:31 PM
Good luck, I hope you didn't spend too much for that.

08-13-08, 08:41 PM
I have $340 into the car. I guess my worries is if I pull the engine and repair the damage, what is the chance of it happening again? This has such low miles on it. I guess I'm just trying to figure out why it happened. Could it have been a flaw in the bearing?

08-13-08, 09:43 PM
At $340 you might as well drive it to the ground. At least it aint over heating. It could actually last awhile with that knock.

08-13-08, 09:52 PM
Sounds like an exhaust leak to me. Give it a couple of neutral blasts. If it sounds like something inside is trying to get out, it's a bearing.

08-14-08, 04:30 AM
Dont know how that happend. Did you check the oil? Maybe its extremly low on oil. Or maybe someone ran it too low on oil and F'ed somthing up. Ive ran the dog crap outa my northstar and its smooth and sounds like its purring at idle...

Just a question. Is it skipping/backfireing? how does it sound from behind? What grade gas are you putting in it? The highest grade... right?

Has the car made this noise since you bought it? Where is the noise coming from exactly?

Ive never personally heard a water pump make a knock noise. But ive heard that bad waterpump bearings could cause a knocking/tapping noise. (something i heard)

EDIT: EHH, Looked at the video. Now that i think about it. Sounds like the engine is F'ED! But we can still help...

08-14-08, 11:03 AM
So what is the easiest(I know,they all suck:o) method to remove the engine? Pull the engine from the top or drop the cradle from the bottom then lift the engine off that?

08-14-08, 12:49 PM
That sounds like it could be on the top end - bad cam lobe maybe? Broken valve spring?

08-14-08, 01:29 PM
There's info going around about premature engine failure caused by not changing oil. Usually valvetrain related and failure in the 15K range.

The easiest way to remove the engine is dropping the cradle.

It might be worth pilling the cam covers for an inspection.

08-14-08, 01:34 PM
I just watched the video.

Hard to tell but it sounds like 2 noises.

Have you changed the oil? If not try that and drain the oil into a clean pan. Look for metal particles in it.

08-14-08, 03:06 PM
Here Are both vids. The second one is with a bit of engine revving

First Vid (http://www3.telus.net/shredon/STS%20Knock.divx)
Second Vid (http://www3.telus.net/shredon/STS_Knock2.divx)

08-14-08, 10:19 PM
Drained the oil. used a 1/2 neodymium magnet on a wire and dragged it thru the oil. A lot. It came out clean! No metal at all. sooo...

Can a bearing spin and not put a speck in the oil pan? Or...does the filter grab it all up? I kinda doubt it.

08-17-08, 03:10 PM
Thanks to everyone for your kind responces!

Update: I cut the oil filter open with a lathe and there is some metal flakes in it :o

So it is most likely a bearing? Could the extra play make the stroke long enough to make the extra sound like a piston is hitting a valve or the head?


08-17-08, 06:10 PM
Bearings often get pounded so you do not get a lot of flakes.

You probably will have to do some disassembly to tell anything.

You can pull the cam covers and run it. Some oil will splash so have some rags.

If it isn't in the heads it pretty much has to be a bearing.

08-17-08, 06:59 PM
Main-rod-cam bearing metal is aluminum/copper/babbit material and is not magnetic (ferrous), but will show up as shiny flakes in the oil filter media. If a rod bearing is really bad it could cause a distinct rap as the accumulated carbon causes interference in the very thin quench area above the pistons in a Northstar......but a rod bearing usually gives a steady, hard knock that may lessen if you pull off the correct spark plug cable.

Does your oil pressure light come on at hot idle ?? I'm discounting broken pistons, rings, or wrist pin failure because those don't usually put flakes in the oil filter.........metal chunks in the pan.

08-17-08, 07:56 PM
I sure appreciate all of your responses! Your opinions and point of view is of great value to me :)

I haven't let it get up to a hot idle...only ran it for 30 seconds out of fear of it chewing up the crank and making a repair impossible. The secondary noise scares me into thinking a valve is getting impacted. So I am worried about it getting bent.

I also inspected the flex plate ( as much as you can see ) for cracks, all the way around, and found none.

08-17-08, 10:05 PM
Has anyone managed to fish the crossover exhaust pipe from the front manifold over the tranny?(with the removal of the engine/transmission mate bracket) If so, it may allow the removal of the engine oil pan.:bigroll:

08-17-08, 10:10 PM
Ok, need to remove both valve covers and inspect your cams, and remove the intake and check your valves, you can 'peer' into each intake port at least and make sure they're all good. Do a proper leakdown test (google it) get yourself an air compressor and the guages, take the time and perform it, it will tell you the status of your intake and exhaust valves, pistons and rings. Then you'll be 90% sure it's your bottom end before tearing into it.