Valve clatter in my '97 Explorer 4.0L SOHC? (Audio sample.)

[Albina]

Hey all. I have a 1997 Explorer XLT, 4WD 4.0L SOHC with what I think is some valve clatter going on. A mechanic friend suggested DELO400 SAE30 and Lucas Oil Stabilizer to eliminate dry starts. I've already got 5 qts. of the oil in and the engine sounds a little quieter, though sometimes it still clatters on startup. Would it be okay to add some Lucas Oil Stabilizer and see if that quiets the valve clatter? My front seal is also leaking a bit, and until that can be replaced I'm hoping the Lucas will slow that. It's not bad as it is, but I'm curious to see what it can do. The rig doesn't smoke at all, and except for the valve noise, runs fine. 185K miles, please see link for how the engine currently sounds, but keep in mind it was fairly quiet when I recorded this. The rattle/knock is sometimes much more audible.

http://www.youtube.com/watch?v=V8EwFTIwLY0

Thanks for any thoughts or input!

 

[my98nnj]

You need to pick up the audio from the engine compartment, not from inside the cabin.
The SOHC is famous for it's timing chain rattle. It could be a loose tensioner your hearing. Try to get the audio right from the area in the engine that's loudest. Also open the oil fill cap and record the noise from there as well.

 

[petzl90]

I had/have the same problem. I say had cause it used to be alot worse than it its now.A Year ago It was very loud, even with a warm engine and it would start from 2k RPM, my local mechanic couldnt figure it out. Now a year later after putting 5w30(it gets so hot down here they recommend 10w30 but I changed back to 5w30) and switching to ethanol free 89 octane gas it only does it at 3k RPM and only when the engine is cold. The Gas made a big difference, my 13 year old engine doesnt like that ethanol.

 

[my98nnj]

it only does it at 3k RPM and only when the engine is cold.

Thats the timing chains your hearing, not valve clatter.

 

[2000StreetRod]

Timing chain rattle

Albina, I suspect that your primary timing chain tensioner has failed if it has never been replaced. It was an inferior design and the available replacement is significantly improved. It usually results in a continuous rattle that increases at midrange engine speeds.

A start up rattle that goes away is more typical of a failed camshaft timing chain guide assembly failure. This can be confirmed by either removing the oil pan and finding pieces of plastic or by removing the valve covers and inspecting the guides. Once a guide assembly fails there is the danger of the timing chain slipping which usually results in the exhaust valves striking the pistons.

 

[ranger7ltr]

Where did you find ethanol-free gasoline???

I had/have the same problem. I say had cause it used to be alot worse than it its now.A Year ago It was very loud, even with a warm engine and it would start from 2k RPM, my local mechanic couldnt figure it out. Now a year later after putting 5w30(it gets so hot down here they recommend 10w30 but I changed back to 5w30) and switching to ethanol free 89 octane gas it only does it at 3k RPM and only when the engine is cold. The Gas made a big difference, my 13 year old engine doesnt like that ethanol.