4.0 Knock Knock!!
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4wd High
Joined: Jul 2012
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4.0 Knock Knock!!
So new here but thought it a good place to get a few tips about a 2000 Disc. 4.0L
So the engine has a knock that seems low and at the rear and have seriously considered the flex plate as mentioned in many threads but can not really confirm but had a question. From the access hole in the bell housing I can use a pry bar and get no movement from the flywheel (thrust) but when bar is placed at the flex plate I can move the TC rearward about 1.5CM, is this normal or a sign that it is in fact the cause of the knock. I did find two allen key screws in the front of the flywheel visible through the access hole and noted that they both had been worn on the edge so removed them seeing that they had no real job and this did reduce the noise but a knock is still present.
I have replaced the lifters as it did sound like that and there were three very bad ones and again a small improvement but this knock is persistent and looking for advice.
So the engine has a knock that seems low and at the rear and have seriously considered the flex plate as mentioned in many threads but can not really confirm but had a question. From the access hole in the bell housing I can use a pry bar and get no movement from the flywheel (thrust) but when bar is placed at the flex plate I can move the TC rearward about 1.5CM, is this normal or a sign that it is in fact the cause of the knock. I did find two allen key screws in the front of the flywheel visible through the access hole and noted that they both had been worn on the edge so removed them seeing that they had no real job and this did reduce the noise but a knock is still present.
I have replaced the lifters as it did sound like that and there were three very bad ones and again a small improvement but this knock is persistent and looking for advice.
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Joined: Jan 2011
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From: Savannah Georgia
You might review https://landroverforums.com/forum/di...rite-up-48197/, and check your oil pressure (bearings worn). You say knock, vs "tick" - for tick there are other choices like pinning a liner, etc.
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4wd High
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Ok so oil pressure cold is (sorry my gauge is in PSI) 48psi and as it warms up it to operating temp it sits about 30-32 all at idle. Seem great to me and I did check as well before I changed lifters to be sure we were not having oil pressure troubles.
So I am about to pull the oil pan and see if I can get a look at the flex plate simply because I am not sure how else to verify. the sound is not like a hard knock like a rod and is not really a tick like a lifter but more of a cross between the two, always there hot or cold and maybe a bit more hot but not a lot and all though it is hard to determine the location of the sound it seems to me more persistent at the rear of the engine and into the bell housing. It always seems the same and increases with engine speed but not in intensity until the engine drowns out the sound at high RPM (it is still there just the engine sound masks it). It seems the same under load as idle so I am not sure what to think.
If it was liner would it not change with temp?
Look forward to your ideas.
So I am about to pull the oil pan and see if I can get a look at the flex plate simply because I am not sure how else to verify. the sound is not like a hard knock like a rod and is not really a tick like a lifter but more of a cross between the two, always there hot or cold and maybe a bit more hot but not a lot and all though it is hard to determine the location of the sound it seems to me more persistent at the rear of the engine and into the bell housing. It always seems the same and increases with engine speed but not in intensity until the engine drowns out the sound at high RPM (it is still there just the engine sound masks it). It seems the same under load as idle so I am not sure what to think.
If it was liner would it not change with temp?
Look forward to your ideas.
Super Moderator
Joined: Jan 2011
Posts: 16,322
Likes: 88
From: Savannah Georgia
Before surgery you might want to remove plug wires one at a time, to see if noise changes a lot, in case problems are related to a rod bearing etc. This isolation will help with diagnosis from below.
Owners with liner problems usually say it starts after block warms up. With pan off you will reveal much, like oil screen clogged, while in there replace O-ring on pickup tube, loctite pickup tube bolts in. If you have the reluctor disk it will look like this, and the tip of the CKP is in that ring of notches to provide the engine position information to the ECU. Note that manual vs auto tranny have different spacer on the CKP. Older style reluctor disks had square metal tabs bent up from notches stamped in a thin disk, they sometimes got bent or even knocked off.
30-32 at idle seems high for oil PSI. Might try another gauge, swap filters out. Would want the 2000 rpm PSI to be above 50. High oil pressure could indicate restrictions. Increased wear of mains will usually lower PSI, knocking, etc.
You may want to also locate the noise and pull the valve cover to have a look at the top of the valve train.
Pix three is a remote possibility, the missing wrench. Those good looking lifters are at close to 200K on a diet of Castrol, then Rotella. The others - deferred maintenance. I'm convinced if guys spent as much on keeping the inside of the engine clean as they do on wheel polish, bumper butt cream, and bikini car wax trucks would last longer.
Owners with liner problems usually say it starts after block warms up. With pan off you will reveal much, like oil screen clogged, while in there replace O-ring on pickup tube, loctite pickup tube bolts in. If you have the reluctor disk it will look like this, and the tip of the CKP is in that ring of notches to provide the engine position information to the ECU. Note that manual vs auto tranny have different spacer on the CKP. Older style reluctor disks had square metal tabs bent up from notches stamped in a thin disk, they sometimes got bent or even knocked off.
30-32 at idle seems high for oil PSI. Might try another gauge, swap filters out. Would want the 2000 rpm PSI to be above 50. High oil pressure could indicate restrictions. Increased wear of mains will usually lower PSI, knocking, etc.
You may want to also locate the noise and pull the valve cover to have a look at the top of the valve train.
Pix three is a remote possibility, the missing wrench. Those good looking lifters are at close to 200K on a diet of Castrol, then Rotella. The others - deferred maintenance. I'm convinced if guys spent as much on keeping the inside of the engine clean as they do on wheel polish, bumper butt cream, and bikini car wax trucks would last longer.
Last edited by Savannah Buzz; Jul 12, 2012 at 05:01 AM.
According to the post I have read about liner issues, you may have liner issues in your immediate future, but the only way to know, is to start pulling stuff apart. Take pix as you go along.
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4wd High
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Well pulling the pan has not really helped much, thought I would see a crack on the flex plate but nothing I can see anyways! So is the converter designed to move when prying as described in the original post?
Engine is clean inside and see nothing that looks suspicious so still stumped!
On your picture of the flywheel you can see the small set screws I spoke about with the allen key head that were damaged or worn off on one side, what is the purpose of these? I did remove them but the sound was still there.
So liner question, what would you look for to identify this issue?
Engine is clean inside and see nothing that looks suspicious so still stumped!
On your picture of the flywheel you can see the small set screws I spoke about with the allen key head that were damaged or worn off on one side, what is the purpose of these? I did remove them but the sound was still there.
So liner question, what would you look for to identify this issue?
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4wd High
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The flywheel looks the same as in the above picture, I don't think they have a ring attached to the back but just use the chain like pattern then a gap for sensor pick up but I am certainly out on my comfort zone on this one. I did remove them and they are threaded into the flywheel and nothing behind so thought maybe they were a balance thing and only two of them both together.!!?? Just not sure but it ran without them.
So any pointers on how to be sure a liner is moving from below? I just cant seem to find any real tell tail signs of a problem that would cause this unless you find the torque converter movement to be abnormal as described above.
So any pointers on how to be sure a liner is moving from below? I just cant seem to find any real tell tail signs of a problem that would cause this unless you find the torque converter movement to be abnormal as described above.
