Knocking sound..
 

98 GMC Jimmy SLS with 138180 miles. It sounded like a brand new motor. It was due for an oil change at around 139.5k miles. Last night I seafoamed it and let it sit an hour. After the hour I drove it around and all was good, got on it a bit to hit redline a few times to clear it all out and it was running like a champ with an increase in low end power. This morning I got in it to move it to my garage to change the oil, at that time I noticed this knock (listen to video below). The knock is directly related to engine speed and seems to be coming from the center-right of the engine bay. I have also noticed a lack of power at the time of the knock.

I changed the oil to Valvoline High Mileage Synthetic Blend 5W-30, it went in very clean, the old oil was pitch black. I also noticed the magnet on the oil pan bolt was covered in shavings. The knock got quieter, but didn't go away.

I drove it a few miles to see if working the oil in more would get rid of it, again it seems quieter but it's still there and if it is what I'm worried about I don't want to put any more miles on it. At the end of that driving a new sound appeared, a sort of creaking (like an old floor or rocking chair) that was present semi-randomly under any throttle. This sound appears to be coming from the left side of the engine bay or dash. It's quiet and semi-random so I was not able to get a recording of it.

Below is a picture of my gauges (oil pressure reaches 60 on acceleration) at idle and operating temperature and a video of 5 seconds of idle and 5 seconds of throttle listening for the knock. This sounds a lot like my Jeep did when it threw a rod.

http://i35.photobucket.com/albums/d1...S15/Gauges.jpg
http://i35.photobucket.com/albums/d1...h_Knocking.jpg

Redlining,,,, it is NEVER good....

I found that out the hard way 20 years ago... engine and tranny toasted...

I used to hit the gas and take off, I mean the gas pedal to the floor, or on the highway just floor it to the point it shifted into 2d or first...

Even saying "to blow out the crap" to redline it is not good...

Now-A-Days I pour seafoam in the tank when I know I am going to go on the highway for a trip or just a casual ride... the crap will come out and no need to redline it....

Yeah, I forgot it wasn't my DSM, thanks for the input.

I just listened to the video and it does not sound good... if the oil is black and you got shavings on the magnet then there is definatly metal to metal without lubercation going on...

I'm not a engine guy but others here are..

And I don't know how many miles you have but on it but you do NOT want to go redlining an older engine or even a new one.

An older engine has wear on it, it is not like a brand new engine as you know..

Not good indeed. I'm just hoping someone can come in and say "Oh yeah there's this weird thing that sounds like a knocking rod but isn't and it's much cheaper to fix"..

I hope for your sake but I doubt it, especially the way it sounds...

hmm mine sounds the similar... getting closer to a 350 swap.....

although mine I hydrolocked.. so i am almost possitive mine's a rod or bent crank

my oil was black with metal shavings as well...



hopefully yours isn't anything major. it COULD be a collapsed lifter...

Redline it a few more times & see if the rods fly out of the engine. If not maybe a Balance Shaft.
I will most likely get flack for what I'm going to say, but here it is. Dumping cleaners in engines with high miles or no miles is crazy in my opinion. I know most of you think Seafoam in a fix for a lot of things. I used it once in the fuel & throttle body & personally I have better results with Lucas Injector Cleaner. Then putting it in the oil & redlining the engine is real crazy IMHO. A mixture of #2 diesel & 5 weight oil does the same as seafoam for much less money. Would you redline your engine with that?
The best way to clean the upper end (valves etc) getting carbon out is to drip water down the throttle body. Ever see a head with a broken or bad head gasket? That is way cheaper than Seafoam. I have nothing against Seafoam I just never saw results that warranted the price or use.

Alright, got it, I done goofed. Any input from the video?

I never put seafoam in my oil, just in the gas tank.

Why would anyone put seafoam in the oil and then redline it? that's crazy...

I read the OP post but I guess it didn't register that he put seafoam in the OIL then redlined it.... DUDE NO WAY, THAT IS A SURE FIRE WAY TO BURN UP YOUR ENGINE....

Just like on engine cleaner it say's, put in a quart and let idle; DO NOT DRIVE, there is a reason for that.... and that is engine cleaner.... Seafoam in the engine is crazy in my opinion....

The seafoam made the oil like water (no lubercating properties), it broke it down and redlining it finished it off.... correct me if i'm wrong here...