jackmac Posted August 18, 2013 Share Posted August 18, 2013 Hi all, Landy has been running great until all of a sudden yesterday it started developing a slight tapping noise after finishing a day at a local pay and play site. No problem thought I, it's just a tappet which can be sorted when I get home 3 miles down the road. Unfortunately, 100m later it turned into a horribly loud metal hitting metal knocking noise, and I finished the journey courtesy of the local recovery firm to avoid (further) damage. The knock is happening about 3 to 4 times per second at idle, and is very loud. I'm sure it's coming from the top of the engine. So far I have removed the rocker shaft to check for a snap (none found), checked the studs holding the rocker shaft and the holes for the 2 bolts (all fine), re torqued that and then checked all the tappets (all fine other than 1 which was very slightly tight). It is losing a little bit of oil from rear crank seal, but has plenty in there and has not run low on oil at all in the last 1500 miles (since I have owned it). Have also removed the fan belt to make sure it wasn't something caught, but that hasn't helped. It didn't feel down on power yesterday at all, although I don't dare try it with the noise it's now making. Any ideas? I could be totally wrong about it being from the top of the engine and it thus could be a big end I guess, but it sounds a bit more 'clangy' than I would have expected from a big end going... Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted August 18, 2013 Share Posted August 18, 2013 When I had those symptoms, albeit on a 2.25 petrol, a very small screw had found it's way into one of the cylinders, and lodged itself into the top of the piston, I was convinced it was a little end gone before I saw that. Being diesel, it could be a lot of other things though, even fuelling, but I will let an expert comment on that Quote Link to comment Share on other sites More sharing options...
Daan Posted August 18, 2013 Share Posted August 18, 2013 sounds like a big end to me. Did it take long for the oil light to go out on start up? It is low oil pressure that would cause it. Daan Quote Link to comment Share on other sites More sharing options...
jackmac Posted August 18, 2013 Author Share Posted August 18, 2013 It's always taken about 1 second for the oil light to go out, I haven't noticed it taking any longer since the noise started, but might have just missed it. Sounds like either head or sump off at the moment Quote Link to comment Share on other sites More sharing options...
mmgemini Posted August 19, 2013 Share Posted August 19, 2013 Crack each injector pipe in turn to see if the knock runs away Quote Link to comment Share on other sites More sharing options...
jackmac Posted August 19, 2013 Author Share Posted August 19, 2013 Crack each injector pipe in turn to see if the knock runs away I'll give that a go tonight. Just loosen the pipe, not the injector itself? When I had those symptoms, albeit on a 2.25 petrol, a very small screw had found it's way into one of the cylinders, and lodged itself into the top of the piston, I was convinced it was a little end gone before I saw that. Being diesel, it could be a lot of other things though, even fuelling, but I will let an expert comment on that I hope it's not a screw! I've phoned a few local specialists this morning and got no more ideas really other than those given in here. Quote Link to comment Share on other sites More sharing options...
jackmac Posted August 19, 2013 Author Share Posted August 19, 2013 Quick video of it. It doesn't get any louder with the filler cap off. Cracking off the injectors didn't seem to change it, did cover me in fuel though! I can't feel any abnormal vibration from the lift or vacuum pump Quote Link to comment Share on other sites More sharing options...
mmgemini Posted August 20, 2013 Share Posted August 20, 2013 Yes expect a bit of fuel from the pipes... Do you still have oil pressure ? Quote Link to comment Share on other sites More sharing options...
steve b Posted August 20, 2013 Share Posted August 20, 2013 Take the vac pump off , you won't feel anything vibe wise if it has failed . It will , however be obvious if it's broken when off. If that's ok then most likely big end . Pop the head off to check - it will be shown by the piston top marking the head cheers Steveb Quote Link to comment Share on other sites More sharing options...
jackmac Posted August 20, 2013 Author Share Posted August 20, 2013 Take the vac pump off , you won't feel anything vibe wise if it has failed . It will , however be obvious if it'sbroken when off. If that's ok then most likely big end . Pop the head off to check - it will be shown by the piston top marking the head cheers Steveb Vacuum pump is off. Looks healthy enough to me although I've not seen one before! About 4mm free play then it is very stiff, I can't push it in by hand but understand that is fairly normal. Yes expect a bit of fuel from the pipes...Do you still have oil pressure ? Yep, still got oil pressure. Sump is coming off this afternoon to have a look at everything... should be able to feel big/little ends there and avoid a potentially unneeded head gasket kit! Quote Link to comment Share on other sites More sharing options...
TheRecklessEngineer Posted August 20, 2013 Share Posted August 20, 2013 Cover the hole in the block for the vac pump (I used a bit of cardboard) and start the engine. See if the knock is still present. Do the same with the lift pump (yes, it will run without it). Then if it's still there, it's head off time. For what it's worth, I had a Discovery that made a similar noise. It was the vacuum pump. Quote Link to comment Share on other sites More sharing options...
Tanuki Posted August 20, 2013 Share Posted August 20, 2013 I had a bowel-rending knock when the long bolt holding the alternator to the engine escaped. Try running the engine with the belt off. Also, check the tightness of the pulley/damper on the crank nose: the big bolt in the centre has been known to loosen itself and progressively mess up the woodruff-key/slot in the crank-nose. Quote Link to comment Share on other sites More sharing options...
jackmac Posted August 21, 2013 Author Share Posted August 21, 2013 Cover the hole in the block for the vac pump (I used a bit of cardboard) and start the engine. See if the knock is still present.Do the same with the lift pump (yes, it will run without it). Then if it's still there, it's head off time. For what it's worth, I had a Discovery that made a similar noise. It was the vacuum pump. Noise is still there with no vacuum pump on. Went to take lift pump off but found it wouldn't budge without removing a pair of injector pipes. Used a listening stick (very long screwdriver) on to the lift pump and I'm 99.99% sure that it wasn't the origin on the noise. I had a bowel-rending knock when the long bolt holding the alternator to the engine escaped. Try running the engine with the belt off. Also, check the tightness of the pulley/damper on the crank nose: the big bolt in the centre has been known to loosen itself and progressively mess up the woodruff-key/slot in the crank-nose. All bolts are tight, including the crank bolt. The video above was taken with no fan belt on. Quote Link to comment Share on other sites More sharing options...
Tetsu0san Posted August 21, 2013 Share Posted August 21, 2013 Take off the top of the air filter box. If the noise seems to get louder and seems to be coming out of the air intake then I would suspect a valve clearance issue. This can be a damaged valve, clearances out of whack, the valve cap missing or the rocker shaft broken or lose. I had a knock which I thought was a bigend and it was where my rocker shaft had broken because one of the retaining bolts had worked lose. A friend had the same sound and it was a valve cap that had worn through. Worth a look anyway. Quote Link to comment Share on other sites More sharing options...
jackmac Posted August 21, 2013 Author Share Posted August 21, 2013 The sump is off now, so can't run it at the moment! Not totally sure about the big ends to be honest, so would appreciate some input! I'm told that the big ends (and possibly mains) were replaced in the last 4k miles. I cannot move any of the big ends up and down, or perpendicular to the crank. I could however slide no. 4 about 0.5mm along the crank (parallel to it), and no. 2 less than that. I also noticed that one of the nuts on no. 2 was not tight at all, in fact it span off in my hand. One of many loose nuts/bolts I have found since buying the truck No movements in the crank on the main bearings so think those are all fine. All tight as well, but I am going to run along them all with a torque wrench. Because I can't feel any movement I don't think there have been causing the noise. There was absolutely no sign on metal shavings in the sump. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted August 21, 2013 Share Posted August 21, 2013 I would bet the loose one on #2 could cause this, it would allow the big end to open up enough to either slap or let the piston hit the head. Quote Link to comment Share on other sites More sharing options...
The Badger Posted August 21, 2013 Share Posted August 21, 2013 Not sure if you tried this already, but take the glow plugs out, and the injectors. Something could have broken off and it between the top of the piston and the valve. One of my glow plugs burnt off and got crushed and bent a valve slightly, only found out when I took the head off to change the gasket. Just read the above, if the piston is coming up then it could crush something? Quote Link to comment Share on other sites More sharing options...
Eightpot Posted August 21, 2013 Share Posted August 21, 2013 Last time I had a knock like that, I found one of the valve caps down one of the pushrod holes. The previous owner had obviously fitted new caps, dropped one somewhere and it fell down the hole, where it was banged against the head by a pushrod each time the cam lifted it. Quote Link to comment Share on other sites More sharing options...
jackmac Posted August 23, 2013 Author Share Posted August 23, 2013 Well, big ends are out now just about to go put the new ones in. 7 out of 8 of the nuts were only really finger tight. A lot more wear than I would expect considering I was told there were replaced in last 5k miles and clearly some dirt introduced last time on number 2 causing heavy scoring. I don't think this lot has been causing the knocking though, but it looks to be for the best that I am replacing them anyway. http://s200.photobucket.com/user/jmac105/media/20130823_162230_zps8b0ef08c.jpg.html'> Quote Link to comment Share on other sites More sharing options...
The Badger Posted August 23, 2013 Share Posted August 23, 2013 I would take the head off if you are going this far Quote Link to comment Share on other sites More sharing options...
Happyoldgit Posted August 23, 2013 Share Posted August 23, 2013 What are the journals like? Quote Link to comment Share on other sites More sharing options...
jackmac Posted August 23, 2013 Author Share Posted August 23, 2013 There is a tiny bit of scoring on the crank where no. 2 sits that I can feel with a thumbnail run across it, other than that it all looks and feels fine. I'm not looking at having the crank reground because I need the car back on the road before too long. If the knocking is still there when I get it all back together, then head off is the next step. Quote Link to comment Share on other sites More sharing options...
Tanuki Posted August 23, 2013 Share Posted August 23, 2013 The bearing-shells where you can see any of the underlying copper-coloured backing (leftmost, and the one with the score in it) are definitely in need of replacement! While you've got it in bits it'd be stupid not to replace the lot. Bearing-sets are cheap; the time spent on an engine-teardown-and-reassemble is expensive. Quote Link to comment Share on other sites More sharing options...
jackmac Posted August 23, 2013 Author Share Posted August 23, 2013 The bearing-shells where you can see any of the underlying copper-coloured backing (leftmost, and the one with the score in it) are definitely in need of replacement!While you've got it in bits it'd be stupid not to replace the lot. Bearing-sets are cheap; the time spent on an engine-teardown-and-reassemble is expensive. May have been a misunderstanding there. I'm not having the crank reground, I am most definitely replacing the bearings though! Quote Link to comment Share on other sites More sharing options...
mmgemini Posted August 23, 2013 Share Posted August 23, 2013 They're in a worse state than the ones I took out of my 300Tdi after running 25 miles with no oil pressure. Quote Link to comment Share on other sites More sharing options...
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