I was changing the oil in my 2004 Chevrolet Siverado 1500 this weekend, and when I was going to put the plug back in, I noticed a few tiny wire-like metal shavings sticking to the magnetic oil plug. They were varying from about 1/8" to 3/8" in length. The shavings were slightly curly/twisted, but about the same thickness as you would see on a wire brush (small fraction of a millimeter).

My question is, how worried should I be? Is it time to start shopping for a newer truck? Or is this expected wear?

Some background info and context that might help answer this question: I bought this vehicle used just a few years ago, and it currently has 190,000 miles on it. It runs very well, and I change the oil every 3-5000 miles, and don't put a lot of miles on it (maybe 5-8000 annually). What might also be very relevant: just a day earlier we bought a new camper, and I was towing it back to the house (about 90 miles). I kept my speed reasonable (60mph max), and I suspect this is the heaviest trailer this truck has ever towed (4200 lbs empty, out of a 6100 lbs max towing capacity on the truck). I do know the previous owner used the truck to tow a small boat (don't know how far or how often). My suspicion is this could be engine "break in" adjusting to towing a heavy load (I have heard an engine and/or transmission will wear differently while towing). Does this sound like a reasonable guess, or are there other things I should be worried about?

  • First step, get them analysed that may help define where they come from.
    – Solar Mike
    Commented Jun 21, 2020 at 18:46
  • The LM7 engine in your Silverado uses aluminum bearings (rods/mains/cam), so if they are magnetic, it's not coming from there. I'd wonder where they are coming from, though ... wondering about lifters or camshaft wear. Commented Jun 21, 2020 at 18:59
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    Considering how much it would cost to open the engine to examine it; I would change the oil and filter before long and keep driving until there were specific symptoms. Commented Jun 21, 2020 at 20:04
  • @blacksmith37 I am considering this as the best option so far, based on what I've read on other internet forums. I may also take the truck to a mechanic I trust, and just have him do a once over (probably not a tear down) and get some general advice, before I start towing our new camper all over the state this summer. Commented Jun 21, 2020 at 21:07
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    FWIW, I found similar filings in a '99 Cavalier. These continued on future oil changes. About a year later, it (suddenly) developed a loud knocking, which we traced to a lifter. Things went downhill quickly after that. I'd lean toward 'be worried'.
    – George
    Commented Jun 22, 2020 at 2:29

1 Answer 1


Because anything which could be said here as an "answer" is a guess, here's what I got for you. It would be my best guess there's an issue somewhere in the valve train and its wearing out. Most likely something is happening with the lifters and/or camshaft. It might also be there's an issue with the rocker arms, but less likely. My reasoning behind this "guess" is because there are really few parts in the LR4 engine (or any LSx style engine) where magnetizable shavings could be coming from.

There are two things here:

  1. Until the engine is opened up and examined, you won't know what's going on. Nobody can really tell you "this is the problem" for sure until it is opened up. Until then, it's a best guess.
  2. The engine would have been broke-in longggggg ago. Whatever is causing the metal shavings is a new event and new wear which should not be happening. Any engine which has any type of metal shavings in the oil (as you describe) is not in very good shape. It could die at any time and will only get worse with time. This engine is going out and there's no bandaid which is going to stop it. Only opening it up for inspection and replacement of the affected parts is going to solve its issues.

Good thing here is, if it is valve train related, you should be able to have the engine gone through with new parts for relatively cheap. An even better proposition here would be to get a replacement engine from a junkyard (or off of eBay or CraigsList). GM made a TON of the 4.8L engines for their trucks (they made even more of the 5.3L ones), which makes them fairly easy to find. It also makes them cheap. Under normal circumstances, the LSx engines can last for 250-350k miles without an issue with proper maintenance. I'd definitely suggest your circumstances aren't normal and it does happen.

Hopefully to make you feel a little better about the whole thing, from what you describe in your towing and maintenance, I doubt there's anything you've done which directly cause the problem or which you could have done better to prevent the issue in the first place. More than likely, whatever is going on has been happening for a while, just now it's happening at a lot faster pace. Something is misaligned enough where major wear is happening at an accelerated pace. You'll need to get this fixed sooner rather than later, as it isn't going to get better on its own.

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