1988 LeSabre T Type vin C motor, 163k miles

http://www.youtube.com/watch?v=HCqs9SAjuVw

It has old oil and old fuel with some fresh fuel mixed in. No stabilizer. Asked previous owner before the current owner if it had a knock when he got it and he said no. It was a daily driver until the PO bought it as a parts car and then decided it was in too good of shape to pull apart.

The knocking makes me think its the old oil not getting up to the top end like it should and its causing one of the valves to stick or something. Guy who has it now says he put in about a half quart of fresh oil and the knocking got less.

Second opinions?

Sounds like a rod knock to me. COULD be a bad harmonic balancer though. Does it have good oil pressure?

What about changing the oil and filter altogether? go buy some SAE30w oil w/o detergent for 1.15 just about any good cheap oil source... Dollar General for me lol. That and a generic filter for $3 and you have a 4.5qt motor, so that'* a $9 oil change. Can't get any better than that.

Try also pulling the valve covers to see if the valvetrain is alright. The front one comes off in a jiffy, so if that one looks good, the rear probably will too. If it'* all sludged up or the metal looks all warped and degraded [bad oil] then uhh your f'd. Or check if the rockers are loose, if they aren't horribly loose and the bolts aren't finger tight it isn't going to be making any noise or at least any loud noise.

If you do have an oil pressure gauge [probably don't tho eh?], if that takes a long time to rise up, that'* a sign of clogged crap oil, and if it'* crap psi to begin with, then she'* done anyways. A quick check with just a dummy light, is timing how long it takes for the light to go off after a dry filter prime. Mine [a 40psi solid motor], takes about a full second with a primed filter for the pressure to start building.

Bad harmonic balancer is an easy check by grabbing the alt fins and trying to rotate the pulley to turn the belt. If it'* all loose and rotates the belt a bit and has an audible hit to it when it grabs, that'* a bad one. If it'* tight so that all your strength can't move it just a bit and it'* more just alt pulley grabbing the belt, she good.

EDIT: now that I've seen the video, man that sure does sound like the HB being ****. Test that belt thing out, and see what happens... you'll know. If not, change the oil with some straight 30w, and maybe a qt of lucas if you want to drive the car. I saw all the gauges rise up real quick, and i saw two, so one had to be volts and oil so i'm gonna assume that'* good, but may be thinned oil, mixed with caustic bad gas.

Sounds like a little bit of everything going wrong.
Cold day
old oil
tired engine
and possibly a bad HB. Try rolling the belt on the alternator pulley and see if you have play. Since the sounds kind of lets up after you goose the throttle, I'm betting that the HB is bad. But there could still be other stuff wrong too.

The car in the vid is actually 300 miles away but I've been asking the present owner to look over some things for me. I'll have him change the oil and check out the balancer. If anything, I'm going to go over the car once I get it and fix it. Worse case scenario I have to put a new motor in but for as cheap as I'm getting the car I won't cry over it.

Does it knock after it is fully warmed up? That could be bad bearings as others have suggested. Or does the noise go away? If the noise goes away, it is not the HB. Could be piston slap from worn pins.

Consider that it is possible to make a bad deal even if someone gives you a car for free.

I think the noise gets less as it goes, but its hard to tell just from the vid.

If its got slop on a piston or whatever, would it still make a 300 mile trip? Once I get it back to Joplin I could put another motor into it pretty easily. Zero rust, perfect front spoiler, and composite fenders really makes me want to get this car, even if the motor craps out on me in a few thousand miles.

did you change the oil? or did you check the level, bc i used to have an old 2.8 that burned oil baddd (1 qt a week) and when low, it would sound similar to ur vid. not as drastic, but similar.

Car is 300 miles away. The guy that has it said he put in about a 1/3 of a bottle and the noise seemed like it got better, so that sounds promising. Hes going to change the oil before I get the car but he'* going back to school tomorrow so I won't know till later...