Replacing the timing belt

Timing belt replacement on a Disco 4 is not an easy DIY job: Dave Barker explains what’s involved when your garage does it

This 2009 Discovery 4, 3.0-litre TDV6 had only recently been bought from a private seller, and the vehicle’s service history was not fully documented. Despite it having a recorded mileage of only 64,000, the Discovery was seven years old and, as such, timing belt replacement was due. The Land Rover service schedule states the Discovery 4’s 3.0-litre TDV6 requires the timing belt to be replaced at 112,000 miles or every seven years, whichever comes first. The 2.7-litre TDV6 needs it replaced slightly sooner at every 105,000 miles or seven years.

Replacing the timing belt on the Discovery 4 is not a straightforward job. It is similar to replacing the timing belt on the Discovery 3, but a little more difficult due to the later emission control system that has been added to the Discovery 4. This includes a number of vacuum pipes secured to the timing belt cover at the front of the engine. The job mostly involves removing pipes and hoses until you can finally access the timing belt cover. Once that can be removed, you then need to pin the timing gears in position to preserve the engine timing before you can remove the timing belt and fit the new belt. To do this correctly a set of special engine timing pins are needed. Two pins are required to lock the two timing gear camshaft sprockets in position, and a third pin to lock the crankshaft into position. Once the various pipes and the timing cover have been removed and the timing gears locked, the belt can be accessed and replaced. This is a job for the professional because the problems it can cause if not done correctly can be grave and very expensive – so this guide explains how your garage does the job. Although not covered here, the fuel pump drive belt should be replaced at the same service intervals.