Lifters

DNTL740

Adventurer
Hello everyone, I have a question that maybe one of you could answer, what does a bad lifter sound like? Five out of seven mornings, and after the car has sat at work all day, I get a medium pitched, hollow loud knock coming from the engine, if I rev it up a couple of times, the sound gets real quiet, but never really goes away. It has been doing this for quite some time, say 50K miles. I am getting ready to do a top end rebuild on the thing, and was thinking I would replace the lifters thinking that maybe one of them is what is making that sound in the mornings. I have removed the pan, because I was told the sound might be a rod bearing going out, rods looked fine, no metal in pan, the engine sounds fine apart from that knock that sounds like a valve out of adjustment. Also I had the oil pressure checked and it was fine, at start up and hot.

Discovery 2001 116,xxx miles.

Thanks, Cristian
 

achampagne

Explorer
I believe a lifter should sound like a tick! and if it sound like a knocks its a rod.
 
Last edited:

REDROVER

Explorer
I believe a lifter should sound like a tick! and if it sound like a knocks its a rod.



yes lifters sound like tick tick tick and when you push the gas that sound should go away.

it should be more when the motor is warm. to check that on your next oil change use heavy motor oil and add that Lucas oil stabilizer.

if no deference then its not your lifters
 

muskyman

Explorer
a worn off cam lob can also cause a knock that sounds like it comes from the top end of the block and will go away with a little bit of RPM. This is very common on the older 3.9 and 4.2 engines.

I have heard this a number of times and then found the worn off cam lobe...in fact I am about to tear one apart right now for the same condition.
 

rovertech

Observer
Hello everyone, I have a question that maybe one of you could answer, what does a bad lifter sound like? Five out of seven mornings, and after the car has sat at work all day, I get a medium pitched, hollow loud knock coming from the engine, if I rev it up a couple of times, the sound gets real quiet, but never really goes away. It has been doing this for quite some time, say 50K miles. I am getting ready to do a top end rebuild on the thing, and was thinking I would replace the lifters thinking that maybe one of them is what is making that sound in the mornings. I have removed the pan, because I was told the sound might be a rod bearing going out, rods looked fine, no metal in pan, the engine sounds fine apart from that knock that sounds like a valve out of adjustment. Also I had the oil pressure checked and it was fine, at start up and hot.

Discovery 2001 116,xxx miles.

Thanks, Cristian

Another cause of a "knock" especially when cold fading with warm-up is a loose cylinder liner. The liner cannot technically drop in a D2 but a cracked block can cause the liner to be loose especially when cold. As the engine warms up and the aluminum expands, the "grip" on the liner tightens and the noise goes away. When you have the heads off I would have the block pressure tested to check for cracks. And as Thom suggested make sure to carefully inspect/measure the cam lobes. :)
 

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