Holey Engine knock!!
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Holey Engine knock!!
So I got the infamous knock in my 99 5.4. It starts loud for a split second then gets quiet but still kinda noticeable. It gets louder the higher the rpm, I mean it sounds like its gonna blow at around 2000 rpm. I've changed oil, filter, checked all plugs and I don't think its coming from the exaust manifold. Which probably means crank bearings or maybe a valve adjustment, which I doubt. Crank bearings would mean a rebuild correct? And should I drive it to the shop with such a bad knock?
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Does the sound go away once the truck warms up a bit or does it always make the noise?
The exhaust manifold leak is more of a tick or snap kind of sound than a knock.
Could be a lot of things, exhaust leak, piston slap, timing chain tensioner failure but unlikely it is bearings unless the truck has over 250k miles.
The exhaust manifold leak is more of a tick or snap kind of sound than a knock.
Could be a lot of things, exhaust leak, piston slap, timing chain tensioner failure but unlikely it is bearings unless the truck has over 250k miles.
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No it doesn't go away when warm. It sounds very internal when I hit the throttle with my head under the hood. Cant post a vid or anything right now. I hope its something else besides bearings but I fear the worst. It only has 90k and had it a month now. The bearing thing keeps coming up the more I research. If someone ran it low on oil for a while, supposedly it would kill the bearings but why now?
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To damage bearings it would have to be really low on oil, so low that the valvetrain would be rattling like crazy. It would take an insane person to actually drive it like this.
Bearings can go slowly but often let go with spectacular results. The heavy metal knock that gets louder as the engine warms can be rod bearings. Neglect could contribute but the bottom ends on these engines are tough.
Even with a little rattle when cold and a leaking exht gasket my truck would run silently once warm. Eventually the leak went pretty much full time so I replaced the gasket and a couple of studs.
Get someone who knows what to listen for, pay them for a diagnosis if necessary.
The rebuild is more than I would spend. Find a good engine from a salvage yard and swap.
Bearings can go slowly but often let go with spectacular results. The heavy metal knock that gets louder as the engine warms can be rod bearings. Neglect could contribute but the bottom ends on these engines are tough.
Even with a little rattle when cold and a leaking exht gasket my truck would run silently once warm. Eventually the leak went pretty much full time so I replaced the gasket and a couple of studs.
Get someone who knows what to listen for, pay them for a diagnosis if necessary.
The rebuild is more than I would spend. Find a good engine from a salvage yard and swap.
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I dont know what the tards before me did so I'm assuming the worst. We've had it a month and its only got 90k so either its my bad luck or somebody slick 50'd it or something. If I have to pay for a rebuild its not a total loss cause it books at 10,000$ and I paid 5,000. Hopefully I get it in the shop this weekend, I'll keep ya posted.
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