Valve cover replacement 2005 Silverado 4.8 - sludge!

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Jul 14, 2020
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I'm finally getting around to the updated valve cover replacement on my 2005 Silverado with 9400 hours and 214k miles...here are the pictures. Much worse than I expected. The first 120k miles my boss (and probably whoever owned it before him) used up all 100% of the oil life monitor before changing the oil with cheap conventional at the quick lube. I used to take his trucks for oil changes when I was the lowest man on the totem pole, the oil change reminder was always on.
From 130k to 190k I was the driver and we took it every 3-4k for regular cheap conventional oil changes. Call it wasteful if you like to jump to conclusions without all the information, but the olm gets to 0% in 4.5k miles due to all the idle time. I work for a land surveyor so we spend a lot of time in the truck warning up when it's -20 outside, or cooling off when it's 80-90 outside.

From 190k to 214k (2 years ago when I bought it) it's used m1 0w40 and m1 EP high mileage still every 3-4.5k miles. I figured it wouldn't be pristine inside so I was trying to clean it out. Clearly synthetic does a better job of keeping something clean than getting it clean after its already been neglected.

I'm going to keep doing what I'm doing and hope it slowly cleans up over the years, but open to suggestions. I posted pictures of my 76 Oldsmobile 350 V8 a few years ago and it had zero sludge anywhere in the engine when I got it from the junkyard, and same after 10 years 100k miles when I did the intake gaskets. I was hoping this one would look like that inside.
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I'm finally getting around to the updated valve cover replacement on my 2005 Silverado with 9400 hours and 214k miles...here are the pictures. Much worse than I expected. The first 120k miles my boss (and probably whoever owned it before him) used up all 100% of the oil life monitor before changing the oil with cheap conventional at the quick lube. I used to take his trucks for oil changes when I was the lowest man on the totem pole, the oil change reminder was always on.
From 130k to 190k I was the driver and we took it every 3-4k for regular cheap conventional oil changes. Call it wasteful if you like to jump to conclusions without all the information, but the olm gets to 0% in 4.5k miles due to all the idle time. I work for a land surveyor so we spend a lot of time in the truck warning up when it's -20 outside, or cooling off when it's 80-90 outside.

From 190k to 214k (2 years ago when I bought it) it's used m1 0w40 and m1 EP high mileage still every 3-4.5k miles. I figured it wouldn't be pristine inside so I was trying to clean it out. Clearly synthetic does a better job of keeping something clean than getting it clean after its already been neglected.

I'm going to keep doing what I'm doing and hope it slowly cleans up over the years, but open to suggestions. I posted pictures of my 76 Oldsmobile 350 V8 a few years ago and it had zero sludge anywhere in the engine when I got it from the junkyard, and same after 10 years 100k miles when I did the intake gaskets. I was hoping this one would look like that inside.
You can see that there is some cleaning taking place .
Just keep doing what you have been , i see no need for flushes or any thing fancy here.
 
You can see that there is some cleaning taking place .
Just keep doing what you have been , i see no need for flushes or any thing fancy here.
I thought that myself... scraping some of the chunks away they appeared like they may be getting broken down...jist a long slow process. I scraped away what I could easily access..
Now I think I'll just leave the rest to time. I'd rather not have harsh chemicals in the oil.
 
All of the sludge seems very soft and sticks right to the screwdriver. Maybe I shouldn't have messed with it but I wanted to get it cleaned up a little bit.
 
I think the "fixed orifice" PCV might actually be plugged up inside which would have just made things worse. Hopefully it will clean faster with the new cover. What do you think the passenger side would look like underneath?
 
I would stop with the screw driver. Change the filter early to remove any lumps you may have dislodged and keep to your existing OCI.
I'm not sure using an expensive oil like Mobil is going to help much at such short OCIs. I'd just use store brand conventional.

Removing the other valve cover might be fun to see inside, but I doubt it's going to change how you go forward from here.
 
I would stop with the screw driver. Change the filter early to remove any lumps you may have dislodged and keep to your existing OCI.
I'm not sure using an expensive oil like Mobil is going to help much at such short OCIs. I'd just use store brand conventional.

Removing the other valve cover might be fun to see inside, but I doubt it's going to change how you go forward from here.
We're coming up on the cold weather where synthetic really has an advantage...
I was going to warm it up and then change it immediately after this job....but I might just run it half an hour to go buy some cheap conventional and a cheap filter, then change it, hopefully after most of what I've dislodged is caught in the filter, then run it a week or so with the cheap stuff and change it again with my usual.
I don't plan on ever going beyond the oil life monitor, even with synthetic. I occasionally use conventional for attempted cleaning but it doesn't stay in there very long.
 

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That's not so bad. A friend got a 91 sierra for free and that thing was pretty sludged but i told him to just use rotella every 5k and its been good ever since. it had an ignition problem but doing the oil change i saw a few slugs come out and took a cover off immediately.
 
Yes, given that the primary purpose of engine oils is not cleaning, any cleaning done will take considerable time, even when using an oil that's advertised as having that ability like M1 0w-40.

Personally, I'd stick with M1 0w-40 and cut open your filters to confirm that stuff is still being removed.
 
Sludge? Are you serious?
Well it looks terrible compared to my Oldsmobile and all the 305 Chevy's I had in the past. Sure it could be worse but the sludge was enough to plug a drain hole which caused the oil to get into the PCV.
 
Penzoil platinum is said to be a good cleaning oil.
I have no clue if that's true
 
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