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on this 4.6l engine, it has a rattling noise at times when I slightly accelerate and not as much when I give it a little more gas.
I researched adjusting the lash but found that I have O lash lifters, no adjustments can be made… is this correct?
if so, would I, or should I be thinking of replacing the lifters? And if so, I would check the push rods and rockers for wear and defects before replacing the lifters… but If I do replace the lifters, do they just pop in or do they need to be primed first ( being Hydraulic lifters)
What else do I need to know?
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I would want to me real sure there is a lifter noise before I did anything. Sometimes a slight pinging or an exhaust manifold leak can sound almost the same as a valve noise.
[quote=”wysetech” post=73899]I would want to me real sure there is a lifter noise before I did anything. Sometimes a slight pinging or an exhaust manifold leak can sound almost the same as a valve noise.[/quote]
+1. a slight exhaust leak can sound just like it.
Yes an exhaust leak could sound like this. A true rattling noise can be a broken catalyst block or a heat shield. With the car cold, jack it up and tap on the cats with a soft mallet and listen for the noise. Seriously; a literal “rattle” as you blip the throttle in Park may be an exhaust issue.
I know these engines can get a fairly loud knock from coking and carbon buildup getting hot and causing a bit of preignition when you try for half to full throttle. 2001 was when the crown vics got the improved valvetrain design.
Just some ideas. I wish i could hear it.
First, you can’t just replace a set of lifters. You also need to replace the cam at the same time. They’re a matched set. Trust me, this presents a challenge since you have to remove the cam from the front of the block. Not much room there.
I’m with the group in locating the source of the noise first. This article might provide some useful insight.
http://www.ericthecarguy.com/faq/diagnosing-noises-in-your-car
If you do believe it’s a lifter noise, make sure you’re using the correct engine oil. If it’s too thick it may not be able to feed the lifters properly. Also, if you’ve switched to synthetic you might consider switching back to see if the noise changes or goes away.
Keep us posted on what you find.
If the rattling noise is not there at idle or while revving in neutral and only happen while at speed, it could be the rattle referred to is pinging and possibly due to an EGR system fault.
[quote=”wysetech” post=74357]Hey Eric…The 4.6 engine is an OHC design and the cams lift out of the heads. Just like a Honda :lol:[/quote]
You know, I had that thought after I submitted my post. After all, I just had one of those in the shop.
Thanks for the correction.
[quote=”Bluesnut” post=74370]If the rattling noise is not there at idle or while revving in neutral and only happen while at speed, it could be the rattle referred to is pinging and possibly due to an EGR system fault.[/quote]
Yes it can be. EGR is active under load, and if that’s when you’re having the problem, it’s possible the EGR is at fault. Do you have any codes for the EGR?
Thanks to all who have responded… i have not done any more diagnostics …but I will take all of your ideals and go forth…
And yes I did switch to synthetic…. will try switching back
and no egr codes.
Pop the valve covers off and push on the lash adjusters, if there is excess play you likely have a bad one. I have had to change out lash adjusters on a a few 4.6 OHC engines so it is not unheard off.
Also make sure you are not hearing chain tensioner noise, the timing chains on those engines are notorious for issues.
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