I added Sta-Bil and the engine started knocking. Uh Oh...

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JimFixes

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So last week I realized the truck is not going to get much movement for a while.

So I cleaned it out, hooked up the battery float charger, tossed 2 bottles of Sta-Bil into the tank (full tank, figures, filled it up then didn't drive it), ran the engine for about 15 minutes to make sure the additive had time to run through and clean things out a bit.

Right as I was going to shut it off, it started knocking. I shut it off before I could record it and then decided to give it a day or two, frankly, I was afraid of starting it, sending a rod through the engine block, and having a dead truck, been there, done that, do not want to do it again.

So, I finally mustered up the courage to start it again, well, I had my wife do it while I recorded, you know, so I could blame her if it blew up lol.

Anyway, this is what it sounds like.

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RichLo

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I'm at work so I cant listen to the video, but the only thing I can think of is 2 bottles may have been too much and it washed the cylinders and is causing piston slap?

When was the last time you changed oil? Maybe you can throw in some heavier oil and lucas oil stabilizer to coat the cylinders again?
 

JimFixes

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I'm at work so I cant listen to the video, but the only thing I can think of is 2 bottles may have been too much and it washed the cylinders and is causing piston slap?

When was the last time you changed oil? Maybe you can throw in some heavier oil and lucas oil stabilizer to coat the cylinders again?

Each bottle is for 20 gallons, and the tank is 42 and was completely full, I also did about 1.75 bottles cause I am a cautious idiot who has learned from his past mistakes.

Oil was changed on the 1st of July, I am religious about changing the oil, cheap insurance. Plus each time I do it the kids and the wife come hang out with me so I get to show them how to wrench on a car and get them familiar with working on them. My 9-year-old freaking loves helping out and my 14-year-old helped me change out the rotors and calipers, she learned how to pack a bearing by hand, preload a castle nut, etc.

But I am thinking that is what has happened, something has loosened up in there.

I cannot tell what the sound is though, I was hoping one of my fellow enthusiasts here would recognize the sound, maybe piston slap, valves needing adjusting, possibly spun bearing but it sounds much closer to the top of the engine than the bottom.

I will be out there tomorrow with my stethoscope to see if I can pinpoint the location.

But frankly, given that it is a major downtime right now and I am coming up on half a million miles, it is time for an upper side tear down, clean and fix and redoing all the seals/gaskets anyway, you can see in the video the top of the intake is coated in a few years of dust/oil/sludge buildup.

Sadly I won't have the funds or time for that until later this year and she is our daily driver, but thankfully not driving much right now.

My hope is someone here comes along, recognizes the sound, and can lead me in the right direction.

Though, come to think of it, I noticed it as I was walking past the exhaust first before coming up to the engine bay, sounded like a puffing from the tailpipe. So almost certainly upper engine, maybe valve seats got cleaned up and need adjusting.

Here is to hoping, thanks for looking. And thanks for the suggestion of a bit heavier oil. I might even have some motor honey around here somewhere.
 

Nick_R_23

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It’s really hard to tell from the video, but the knock appears to match the crank speed, so you likely have a rod knock.

You can throw a timing light on each plug wire and see if the knock matches a certain cylinder. You can also pull the valve covers, and check your valve lash at each cylinder on TDC. You will definitely notice if one is loose enough to knock.

What does the sound do when you rev it a bit and then let off?
 

JimFixes

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It’s really hard to tell from the video, but the knock appears to match the crank speed, so you likely have a rod knock.

You can throw a timing light on each plug wire and see if the knock matches a certain cylinder. You can also pull the valve covers, and check your valve lash at each cylinder on TDC. You will definitely notice if one is loose enough to knock.

What does the sound do when you rev it a bit and then let off?

Great ideas, I will be heading out there this weekend to take a look.

I did not rev it at all, I obviously should have to see if it was engine speed dependant. Chalk that one up to being freaking exhausted with work lately. Not thinking straight on the basics.

Also try putting your ear down under the truck by the flexplate. That rhythm didn't sound right for valvetrain or a rod knock from behind the keyboard.

I thought the same, but in person, it sounded much higher up in the engine compartment, could just be acoustics though.

I will be out there with my stethoscope tomorrow giving her a good check over.

Frankly, at the mileage she is at right now, it is about time for a full overhaul as it is. I am just not financially ready for that right now.

I will keep everyone updated, if there are any other ideas, please send them my way, happy to take any suggestions, no matter how off the wall, I am always amazed at the crazy **** that works.
 

Schurkey

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tossed 2 bottles of Sta-Bil into the tank (full tank, figures, filled it up then didn't drive it)

Each bottle is for 20 gallons, and the tank is 42 and was completely full,
WHAT VEHICLE? WHAT ENGINE? WHAT MODEL YEAR?

WHAT Sta-Bil" product did you use? Sta-Bil has AT LEAST seven different products--Storage, Diesel Winter, Pump Protector, Diesel, Small engine, 360, 360 Marine, and perhaps others.

HOW MANY OUNCES did you install?

Best I can tell, an 8-ounce bottle of "Storage" is advertised as "Treats 20 gallons". So you must have added two, eight-ounce bottles to a full, 40+ gallon tank? "Best Practice" is to add the stuff to a mostly-empty tank at the gas station, then fill with gasoline--so that adding fuel to the tank causes the Sta-Bil to mix with the gasoline due to turbulence in the tank.

First Guess: Total coincidence that the truck started knocking. I've lost all faith in Sta-Bil doing ANYTHING--useful or harmful. I used it for years on seasonal engines. Then I quit using it, and never noticed any difference.
 
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