This LRO reader emailed LRO.firstname.lastname@example.org to ask our experts about the source of tappet noises from within the engine bay of his Discovery 300Tdi powered One Ten.
Five years ago I rebuilt my 1983 One Ten station wagon, replacing the V8 with a 300Tdi from a 1996 Discovery plus a Defender R380 gearbox and Discovery transfer box. It’s been fantastic apart from a ticking noise on tickover. This has got louder recently and I can hear it in tune with the engine running at speed. What could it be?
Dave Kitchen, N Warks
A lot of things in an engine can cause a ticking noise; and without the benefit of a stethoscope it can be difficult to pin down precisely where it’s coming from. The most common cause on Tdi engines is the tappets – it may be a simple case of adjusting them or they could need replacing, which involves removing the cylinder head.
Start by adjusting them, making sure all the small tappet caps are in place between the valve head and rocker arms. If tappet adjustment is a long way out, the caps can fall off the valve, causing an even larger gap.
This workshop advice appeared in the February 2016 issue of LRO. Back issues are available to download on digital devices here.