Glow Plugs for Discovery 3/4 with 2.7 TDV6 Engine

Don’t try this at home!

Glow Plugs are a high risk job on the TDV6 2.7 litre engine, and Roverworks got to experience firsthand the challenges of undertaking the complicated process.

The customer had failed glow plugs, with the usual symptoms of difficulty starting when cold, and the glow plugs needed to be changed. There are 6 of them, located in the valley of the engine. Unfortunately, this is a high risk job – sometimes they come out easily, other times they do not.

In this case, the glow plugs were seized in the holes badly. What seems to be the problem is that rock hard carbon forms in the tight clearance at the bottom of the glow plug, and effectively seizes the plug in the hole so that it cannot be unscrewed. The threaded part of the plug is right near the top, and the long thin shaft of the plug is quite delicate. This is not a “Land Rover” problem – the engine is used in a number of other vehicles – and also, the same thin kind of glow plugs are in many other modern diesels.

In this case, is that 3 of the plugs came out, and 3 (one on one head, 2 on the other) broke off in the holes. 2 broke below the threaded area, one broke halfway through the thread – meaning it still needed to be unscrewed to get the thread out, as well as the shaft needing to be extracted.

What makes it high risk is that if the job gets to this stage, the engine needs to come out, the heads need to come off, and the plugs need to be soaked, warmed, coaxed, cajoled and skull dragged out – all without damaging the head. Remember: alloy heads can’t be heated beyond warm, and you don’t want to damage the heads. The threaded one needed an “easy out” wresting match, and the others needed tapping out in an operation that took a lot of hours. The threaded one came out in 5 pieces, it was that well seized in the hole.

The only good thing about this – the engine was just about on the 168,000 mark where you do cam and fuel pump belts, normally a major job in itself. This allowed us to change the belt kits for just the cost of the parts – the labour was going to be the same putting it back together with the old belts as the new.

The era of being able to do this kind of thing at home is pretty much over – with a fully equipped workshop, a man who is a fitter as well as a 50 year old career mechanic, this was a pretty awful job.

Roverworks lives for these types of seemingly hopeless engine problems, and we can diagnose/repair with qualified expertise at a reasonable cost. Call us today at 02 6241 8777 to book your vehicle for inspection.