Is my 4.7 motor dead?

[jrmyrnsm]

Well I've got a 2003 GX 470 with about 220k on it and its been pretty bullet proof for the 3 years I've owned it. I got out yesterday with the engine still running to grab the trash and heard it make a kind of clunky noise so I cut it off and checked the oil and trans fluid, both of which looked ok. Cranked it back up and it ran for about 10 seconds and shut off suddenly. Let it cool down a little and tried again to get a video of the sound it was making and I've got my suspicions but wanted to see if someone with a better ear could give a probable diagnosis from listening. Wasnt sure the best way to share the video but heres a quick video I put up on Youtube. It sounds kind of ok for the first 20 seconds or so and then starts to make some sounds I'm a little nervous about. Any and all help is appreciated!

December 8, 2022 - YouTube

 

[rdruss]

What's your timing belt status?

 

[Oldmanb777]

Timing would be my first guess also. Hard to hear, but that last few seconds before it quits sounds like that.

 

[jrmyrnsm]

Timing belt was done about 10k ago, would it run if the belt were broken?

 

[AuSeeker]

Timing belt was done about 10k ago, would it run if the belt were broken?

No it wouldn't run if the belt was broken...but it could run if it slipped a tooth on a timing gear.

That being said, the best I could hear from the video IMHO it sounds too good in the beginning to be even a slipped tooth.

It could be starving for fuel, bad coils or a failing computer causing it to start to misfire.

Unfortunately you're going to have to do some trouble shooting/diagnostics to find out what is causing the issue, hopefully it's not terminal.

 

[rdruss]

Can't imagine the engine itself is terminal unless it has been previously overheated, or run low on oil, or something similar that could lead to a durability failure. Maybe something broke, "the clunk", but have you tried to drive it at all since this episode?

 

[rdruss]

I listened again to the video a couple of times, Auseeker is giving good advice. Maybe a cam position sensor, or crank sensor too. weird! Keep us posted.