Knock Knock?

[1976_michelle]

who's there? Nah.. I wish

Will be taking the bus in to see if mechanic can diagnose the knocking sound (fairly recent development I think). Ongoing history of occasional minute coolant loss since before the time of purchase 3yrs ago. (some months no change, other requires 100ml or so top up). Knock audible at startup (no difference if starting cold or starting warm), can't hear it once you get higher rpms, and no performance issues. No water in sump, no overheating. 146xxxkm, oil changes generally every 5000k but we're a 1000 k over that this time. No warning lights. COolant flushed and changed every 12 mo or less. Wouldn't say it sounded like a scrape, it's a knock sound (sounds more substantial than my old crowns tappets used to sound, and I can feel it when I rest my hand on the handbrake if that makes sense). Can't hear it from outside though

Basic research has come up with a few options;
Rebuild if required (could use input on possible central vic providers if you have any though we do have rebuild mobs here in Bendigo, so as long as I specified whatever goodies are recommended such as flanged liners, metal dowels, etc)

JE Robison Service - Bosch Car Service Specialists — the blog: Should You Rebuild or Replace Your Land Rover V8? (http://robisonservice.blogspot.com.au/2013/10/should-you-rebuild-or-replace-your-land.html)

Other possibilities... cam shaft and main bearings (checked for with a look at the sump oil for metal fragments?)

Some are recommending checking the oil pressure at 4 specific temperature ranges (though not sure if that was to check Lifters?). And or Oil pump? (covers can be replaced, or gears),

If I'm lucky manifold gaskets according to a hit on this site from someone else thats had a knocking issue,

Is there anything I've missed when I reel off possibilities for the mechanic? Or a preferred diagnostic path to eliminate particular options?

Thank you

[Scouse]

If you're taking it to a mechanic, the last thing he'll want to hear is internet theories of what it might be.


Give him some free time with the car & let him diagnose it.








It might well be in the handbrake... :)

[1976_michelle]

he's had value from your recommendations on this forum before so thought I'd ask. generally I just write them down on a bit of paper, take it in and say right, this is what I've noticed with the car, bit of paper shows a few clues that might mean something to you, ring me when you know something lol.
Actually input from the forum saved me getting fuel pump unnecessarily replaced too (fuel pump first diagnosis, I posted the result here and was strongly urged to ask mechanic to do a specific couple of tests and though I felt uncomfortable insisting he do so, he did the tests and found fuel pump fine, and narrowed it down to MAF sensor ). So, I'd rather he roll his eyes when I hand over little paper of cheats, than miss a little pearl of wisdom that only someone who's been working on landies for years, might know.
but thank you, I do understand your point

[clubagreenie]

If you're going to go to the length of top hat liners then may as well go 4.6 at the same time, and send the ECU off to Mark Adams for a reprogram while off the rd. You won't know it when it's back.

I have a two builders here that I trust, one I'd have do liner work and rover V8 build for longevity work. But my rate is $200/hr. Hence he does major machining and advisory on my maths and plans and I assemble (oft under his supervision for more ambitious stuff).

Other option is see what TR Spares in Adelaide have.

As for the noise, does it change with RPM? What sort of note is it, lower (knocking) or higher (tapping, like lifter). Deep knocking could be bad (bearing). Handbrake is usually an issue on TD5's.

[bee utey]

It would probably help if you start the car cold, open the bonnet and listen closely to see if you can get an idea of the general location of the noise. You could be so lucky to just have loose or cracked exhaust manifolds, an easy fix. You could have a cracked drive plate to the automatic transmission, this does often get quieter with revs. Any problems with main engine bearings would also lead to low oil pressure and probably a flickering oil light at hot idle. Bearings also tend to make more noise at higher revs.

[1976_michelle]

Couldn't tell you the tone without a comparison (only other I've heard was a recurring tappet problem with my 72 and 74 crowns.. this sounds deeper than that sound). Problem is not the handbrake just I can feel the vibration that accompanies the noise (was just an observation). Disappears with higher RPM (eg as soon as start to drive the sound goes, only hear it coasting at low speeds). The knock itself, when audible.. might be roughly 216 per min (though would vary with revs)

[1976_michelle]

It would probably help if you start the car cold, open the bonnet and listen closely to see if you can get an idea of the general location of the noise. You could be so lucky to just have loose or cracked exhaust manifolds, an easy fix. You could have a cracked drive plate to the automatic transmission, this does often get quieter with revs. Any problems with main engine bearings would also lead to low oil pressure and probably a flickering oil light at hot idle. Bearings also tend to make more noise at higher revs.

Will start car cold and get my head under the bonnet tomorrow. No oil light issues (though haven't tested oil pressure.... guessing Mechanic will)
Thankyou

[RickRover]

From the symptoms you describe, my money is on piston slap. Noise only there on light idle, no oil light so pressure good(!) noise disappears when revved or under load.

[1976_michelle]

From the symptoms you describe, my money is on piston slap. Noise only there on light idle, no oil light so pressure good(!) noise disappears when revved or under load.

... ugh.. wonderful...

[Pedro_The_Swift]

and send the ECU off to Mark Adams for a reprogram while off the rd. You won't know it when it's back.



are you teasing me on purpose???:p




and theres a reason its called slap,, 'cos thats the kind of noise it makes,, your description sounds deeper,,

[1976_michelle]

Actually listening to it under the bonnet... I think maybe something on the serpentine again (the last little noise 'went away' and 'might have been ' a.. somethingorother the mechanic was not perturbed about (especially given the noise was gone and all the bits that should turn easy or not easy or whatever, did as they should).
Not posting the recording because for some reason, recording devices don't hear what I hear and it makes the car sound like a chaffcutter when she doesn't sound that way lol.
Might have been scaring myself for no reason this time, sorry

[Jazzman]

From the symptoms you describe, my money is on piston slap. Noise only there on light idle, no oil light so pressure good(!) noise disappears when revved or under load.

Correct me if i'm wrong. But if he had piston slap that would indicate worn rings and cylinders?

I had worn rings and cylinders (13 thou) on no. 1 & 5 in my TD5. No slapping sound. But I did have bad blow by.

If 1976_michelle does have sldp, would it be reasonable to remove the oil filler cap and check for blow by to help confirm this may be the issue?

Also, could it be the turbo? When boost pressure picks up the noise disappears? Just a thought.

[Scouse]

Also, could it be the turbo? When boost pressure picks up the noise disappears? Just a thought.I very much doubt the noise will be from a turbo...

[clubagreenie]

I can't remember if yours has ACE or not, but the ACE pump low on oil will clunk like a bearing.

Can't be turbo, V8.

[RickRover]

Correct me if i'm wrong. But if he had piston slap that would indicate worn rings and cylinders?.

No not necessarily, a worn piston skirt is all thats required. Would not even show on a pressure test. May not even show up on cylinder walls either.

IMO it is best to investigate all possible root causes and conclude with a satisfactory repair.

[Jazzman]

No not necessarily, a worn piston skirt is all thats required. Would not even show on a pressure test. May not even show up on cylinder walls either.

IMO it is best to investigate all possible root causes and conclude with a satisfactory repair.

Fair enough. I remember having cracked pistons in a VK I6 and it had that exact example.

[Pedro_The_Swift]

Piston slap is repeatable.
time after time.

If the sound has changed----;)

[scarry]

Could be the harmonic balancer?

They make a nice knocking noise when they are stuffed.

[1976_michelle]

Mechanic had a listen today, and is quite content it is the Idler pully /tensioner ?assembly. But also, my Serp belt is shot. Again (only replaced 5000k ago.. so I will be looking up who I purchased it from and making sure not to purchase from them again, looks liek I ended up with heat affected or old stock though the cracks were not visible upon arrival).
Unfortunately.. I didn't quite hear the explanation but a simple bearing is no the fix this time (I thought I heard him say he'd be getting the metal one so that next time it will just be a matter of pushing in a new bearing).. so lord knows what is on it now but anyway...
Unfortunately he'll be getting the parts from LR (god help me but I haven't the time to wait for mail order sellers nor do I want perished parts again).

[Pedro_The_Swift]

any decent bearing place can order a belt to suit, (there are a couple of different lengths, ACE etc)some may actually keep one on the shelf. Any brand supplied by a reputable shop will be Ok,, my last one was a Gates I think,,
The belts will run Ok even with bits missing from the V's,https://www.aulro.com/afvb/images/imported/2015/09/359.jpg

My green D2 idler was worn down to the ribs.

I actually heard your chaffcutter noise yesterday,, some gold V8 D2 went past me and THAT was the noise..
sounds exhaustish to me.

[Jazzman]

Mechanic had a listen today, and is quite content it is the Idler pully /tensioner ?assembly. But also, my Serp belt is shot. Again (only replaced 5000k ago.. so I will be looking up who I purchased it from and making sure not to purchase from them again, looks liek I ended up with heat affected or old stock though the cracks were not visible upon arrival).
Unfortunately.. I didn't quite hear the explanation but a simple bearing is no the fix this time (I thought I heard him say he'd be getting the metal one so that next time it will just be a matter of pushing in a new bearing).. so lord knows what is on it now but anyway...
Unfortunately he'll be getting the parts from LR (god help me but I haven't the time to wait for mail order sellers nor do I want perished parts again).

If your idler tensioner is buggered, likely because the bearing is shot, wouldn't logic dictate the new belt was never the issue? If the belt was slipping on the tensioner pulley when it jammed momentarily it would generate friction and heat in turn damage your new belt.

Just my 2 cents for what it is worth.

[clubagreenie]

Could be the tensioner spring broken, they jamb against they other half and still kind of work, the belt flaps a lot, making a small racket that can't readily be identified or the tensioner pivot bearing damaged (can't be replaced) and again belt flaps on loose tensioner.

Never seen a steel pulleyed one, except mine as it has a falcon pulley the right size and a double bearing.

[1976_michelle]

yeah I don't get it either.. but when the belt was taken off and every thing that runs on it was tested for soundness, everything came up trumps. Except for the severely delaminated belt... ( chunks out in multiple places as well as cracks all the way around).
https://www.aulro.com/afvb/images/imported/2015/05/1187.jpg (http://s1292.photobucket.com/user/Leadfootlodge/media/randocrap/20150506_165604_zpskx5bzuro.jpg.html)

I'm probably going to get shot for this but will proceed because it is interesting and useful for someone else who doesn't mind a bodgy job to get out of trouble some time

Due to a little late organisation on mechanics behalf (must have left it until today to grab the parts instead of buying them when I booked the car in), he was not able to get the right size belt, so he has temporarily improvised with the next size shorter one and skipped a pulley. (he tried to call me, presumably to put me off a couple days but I was already on my way to pick car up and had misplaced my phone). The right belt is coming but meanwhile, i have this;
https://www.aulro.com/afvb/images/imported/2015/05/1188.jpg (http://s1292.photobucket.com/user/Leadfootlodge/media/randocrap/20150506_165453_zpsxmz4rbhx.jpg.html)

Hard to photograph but the shiny one has been bypassed (have been assured the only thing affected by this will be the aircon, so will not use aircon till proper belt is on). It is running perfectly, no sound at all, so unless that is the pulley that is dying (though he says it isn't) it really was just due to the belt. Going by that damage I'd say it's very lucky I've been mainly commuting via train to get to work for the last 6 months

4.6l upgrade postponed at this time :)

[clubagreenie]

As long as things are rotating the right direction