HELP!! Engine Knock After Oil Change

[autoworks856]

hello.

i have a 1998 gmc yukon 4wd, 133k miles, just recently did an oil change, and some other preventitive maintenance. before all that was done, everything was going smoothly, but maybe 2-3 days after i did that, i noticed a slight tap, but i really didnt pay it any mind, until i parked at a store on friday, and when i started the truck again, it started knocking like CRAZY!

i havent driven it much at all the last 3 days, only to work and home. and it as died off a little bit, and now is not as loud as it was friday. WHAT COULD IT BE??? it has oil in it, so i know its not low.

I used Valvoline High Mileage 10W30, and a carquest filter, if that helps anyones diagnosis

 

[AtomicHoe094]

have you checked the dipstick after you did the oil change? how much oil did you put in it? are you sure you tightened up the drain plug? does it leaks? smoke?

also isnt that high mileage oil supposed to be heavier or something? maybe its just too heavy for the oil to get in the lifters and such... idk just a guess..

 

[h0tr0d]

Do you know if it sounds like lifter tick? or does it sound more like the bottom end?

How's the oil pressure at idle and when running?

Do you recall revving it way up while the engine was still cold?

 

[autoworks856]

-atomichoe

plug/filter both tight
oil level is good
no leaks/smoke
yes, the oil is thicker, since it originally calls for 5w30,but i doubt its the oil.

---------- Post added at 03:51 PM ---------- Previous post was at 03:50 PM ----------

-hotrod

it could be anything, but i think its bottom end
oil pressure is good
i dont rev the motor when it is cold

 

[blueflamed03]

odd, should be roller cam motor, so shouldn't have a noise. wonder if a galley is plugged, not letting oil get to a rod journal, cam bearing, etc...

 

[h0tr0d]

I'm going to throw this out there, but don't take it too seriously. If it sounds like lifter tick, then you may have something like a partially blocked galley. If the knocking is a little more substantial it could be something like a spun bearing or something.

The first thing I would do is to get that high mileage shi7 out of your motor immediately and put in some regular oil and see if it stops the sound. While you're at it closely inspect the drained oil for any metal particulates indicating lots of wear.

You could always pull a valve cover and crank the motor with the coil disconnected to verify that oil is getting up to all of your lifters. If that's not it, you could pull the oil pan and inspect the bottom end...but it's still going to be hard to tell without pulling the motor.

Without actually hearing the motor, it's very hard for anyone to diagnose a knocking sound over the internet. Can you maybe take a video and post it to youtube?

P.S. To freak you out a little more I had almost the same exact symptoms, very loud knocking...then quieted down for 10k miles...then horrible after that. Pulled the motor and had spun a crank bearing by revving high with some heavier oil in the truck. If I had pulled the motor earlier, I could have probably gotten away with new bearings and a crank polish, but since I let it be for a while, I ended up having to have the crank welded and it cost me about $400 in parts/machine shop labor

 

[autoworks856]

well ima jus drain the oil, nd put the regular 5w30 in it.

is using seafoam to try and clean out the motor a good idea with these 5.7's??

 

[h0tr0d]

You should be fine running 10w30 especially right now during the summer. What atomic was talking about is the "high mileage" stuff usually has more additives to make it fill score marks and whatnot that essentially makes it "heavier."

People do use seafoam to clean 'em out, but personally I think it's beyond that point.

One more question, is it running smooth or is it sputtering?

 

[autoworks856]

runs smooth as butter, just noisy

---------- Post added at 05:13 PM ---------- Previous post was at 05:11 PM ----------

nd all of this started after te last oil chg, which was 2 fridays ago, it was somewat noticeable the tuesday after, and very noticeable as of last friday.

 

[Danny_Z56]

well ima jus drain the oil, nd put the regular 5w30 in it.

is using seafoam to try and clean out the motor a good idea with these 5.7's??

I would not use Seafoam in your motor oil.Their are better products out there for that,'Auto RX,GM cleaner,full systhetic motor oil,ect...

I and many others have only used Seafoam in our intakes.From what i did and as far as i could tell,the best way to run the SF is through your brake booster hose,(vortec 5.7).

On my LT1 Caprice's and 4.6 Crown vic's i always used the PCV tube that leads into the throttle body.I did not see a way to do this on my Tahoe.

You may watch some youtube vids on "seafoam Tahoe".Most if not all do it wrong.....This BS with pour some in your intake and the rest in the gas tank and or crank case crap is nonsense.myself and many others just pour the ENTIRE can through the intake.Adding some to your oil or gas tank is a waste of money.

This is best to do when the motor is hot and with someone.My wife has helped me on many of my SF treatments.It helps to have someone to give it some gas when adding the treatment (helps keep the motor from stalling).Once the can has been sucked dry,tell the person to shut off the motor!! Let vehicle sit for a good 15 minuts and then start her up.It may not want to start right up,thats ok,just keep trying untill it starts,Once it does you can either rev it in your driveway or take it for a spin.its best if you drive it,their is gonna be alot of smoke and you don't want the FD called or pissing off your neighbors.

Again,if you are using someone to help keep the motor running when adding the treatment,don't have them rev the piss out of the motor.Just have this person give it just enough gas to keep the motor running.Maybe 2-3 hundred RPM above idle.....Otherwise you run the risk of sucking the SF right through the intake system to fast and it not doing anything for ya.

---------- Post added at 07:31 PM ---------- Previous post was at 07:11 PM ----------

Also i agree,stay away from that 'high milage' oil sh*t.

From what i have heard they put alot of detergents in that sh*t that are not real good for basic lubrication.Also could damage gaskets,seals,ect...

Again,this is just what i have heard and tends to make sense.