Intermittent Td5 tapping is back and louder!

Nanocom and cylinder balance test might indicate something

Mine tapped under load at one stage, but I could hear it sometimes at idle as well. It turned out that the chain tensioner had jammed so the chain was moving around and making tap tap noises.
It is easy to find out at least.
If you look at the front of the engine, about half way down the left hand side is a large nut. Undo it and pull the chain tensioner out and see if it still goes in and out

Thanks both, timing chain adjuster is a good start, will check it out, and yup, it's due a plug in as no 3 injector has not been 'set/recognised' by the ECU yet. Just got to find the time to get down to PCB! Thanks guys!

My TD5 Defender had a similar tapping noise. First time it was a cracked heat shield on the left side gearbox mount, bloody drove me nuts for ages trying to find it. Would only make a noise when backing off. Second time was the turbo cover cracked and vibrating around 2000 rpm. Third time was the fan belt tensioner pulley bearing starting to fail and it took me a while to realise the tapping noise was happening only when the air con compressor was running. Fourth time the weight thingy on the back of the transfer case broke a bolt and came loose. fifth time I will do as someone has already suggested and wait for whatever to fall off.

Rick

Back again, and now 100% set that it's the hydraulic followers at fault as there's a new fault tied in with it all. When cold, the vehicle starts and runs well instantly on all 5 cylnders. When warm, the engine fires up on 4 cylinders with a resounding/timed thumping noise coming from the snorkel suggesting to me that one of the followers is draining down allowing one inlet valve to leak. This goes away after about 5 seconds. If it was an injector fault, there'd be no noise from the air intake.......

Have you had the head done?
I have seen this on TD5s with a head gasket on the way out
they leak a little water into the cylinder and it does what you are saying
Is it using coolant

Yeah, did the head gasket about 10000km ago, soon after I bought it. Since then it's not used a drop of coolant. The tapping was there before and after I did the gasket....

@sitec - what was the solution to the tapping noise?