Dreadful engine knock

[mede116]

Hey y'all and Happy Holidays!

Started me car up earlier this week to get to work and while backing up from the driveway, heard this dreadful knock/stutter/shaking (video below). Long story short: I did some digging, removed the intake manifold, and found white gooey liquid inside of it, which, if I'm right, indicated failing manifold gaskets because of the mix of oil and engine coolant (my coolant level had dropped). I changed the gaskets, got new fuel injectors (possibly overkill), and replaced fuel injection pressure damper. Put it all back together, same noise/knocking. I will add that one of the intake manifold mounting screws might be bad as it just keeps turning without torqueing.

Found a video on YouTube that had similar noise. The guy identified the catalytic converters as the source of the noise. Reason I changed the fuel injection pressure damper is because of the fuel I've been noticing in the intake manifold for some time now.

Have no idea what this could be, but I plan to take the cats out to inspect. Any ideas?

NOTE: I've been having a long-standing issue with the valve cover gasket not containing oil in despite changing both the cover and gasket multiple times (eventually using silicone for added seal). The smoke you see from the exhaust manifold is the leaked oil burning.

Thanks!

 

[mede116]

UPDATE: It's the valve spring (pictured below). Also noticed some play in other rocker arms with intact springs; the arm above the damaged spring has excessive play. What are my options now? Is it possible to replace just the springs and rocker arms, or do I need a new engine? What could have caused this?

 

[boominXplorer]

Just swap valve spring and stem seal while your there. The rocker should be fine, the valve springs are a common failure but not enough of an issue to warrant replacing all of them.

 

[boominXplorer]

The rocker should move side to side but not up and down unless the lash adjusters have lost its prime (if you turn the motor over by hand a few times it will loose prime). In that case you can see the tip of the lash adjuster going up and down.

 

[mede116]

Just swap valve spring and stem seal while your there. The rocker should be fine, the valve springs are a common failure but not enough of an issue to warrant replacing all of them.

Thanks for the reply.

Are you sure I don't need to replace all of them? Read a couple of sources saying you should, as the failure of one indicates potential failure of others in near future. Already ordered the parts.

 

[mede116]

The rocker should move side to side but not up and down unless the lash adjusters have lost its prime (if you turn the motor over by hand a few times it will loose prime). In that case you can see the tip of the lash adjuster going up and down.

Thank you!

 

[boominXplorer]

It's up to you on if you want to replace them all. I did one for a friend about 3 years ago and just replaced the broken one and he hasn't had an issue out of any of the others.

They are fun to do in the truck with the head on. I use a tool that uses the cam to push down on the top spring hat and use a compression tester adapter to airlock the valves shut with shop air.

 

[mountaineer2004]

Just swap valve spring and stem seal while your there. The rocker should be fine, the valve springs are a common failure but not enough of an issue to warrant replacing all of them.

Is this a maintenance item, or just unusual bad luck? I had a (great but non-local) mechanic change my tensioners and guides at 175k. So far the engine is still running well at 264k. You mentioned "valve springs are a common failure point". Should I be worried that this is def a future problem?

 

[boominXplorer]

Is this a maintenance item, or just unusual bad luck? I had a (great but non-local) mechanic change my tensioners and guides at 175k. So far the engine is still running well at 264k. You mentioned "valve springs are a common failure point". Should I be worried that this is def a future problem?

It's mainly just a 4.0 v6 and 3v v8/v10 engine problem. Your good to go with the 4.6 2v.

 

[mountaineer2004]

^^ Great news, thanks!