Cold-start problem

On frosty mornings, I have trouble starting my 2006 Range Rover Sport HSE 2.7 TDV6, with 129,549 miles on the clock. Normally, the engine starts and goes well. I have been told that the glow plugs could be at fault and they tend to snap on removal. I have also been told using a penetrating oil called Deblock half-an-hour before removal will help. Kevin Fleming

I agree that the most likely cause of the poor starting in cold weather is failure of the glow plugs. These can be tested without having to remove them by using an ohmmeter. The standard resistance of the glow plug should be between 0.1-6 ohms. All of the plugs should give a fairly close reading.

To test the resistance, disconnect the glow plug from the feed wire and place one side of the meter on the top terminal of the plug and the other on the cylinderhead. Any reading outside of the tolerance will indicate either an open circuit or a short/failed heater plug.

When attempting to remove the glow plugs, ensure the engine has been run up to temperature and has begun to cool slightly, then soak the top of the thread with penetrating oil. After leaving it to soak for about 15 minutes, attempt to remove the faulty glow plugs. The book time allowed for replacing all the glow plugs is 1.8 hours.

Deblock Oil is a mix of quick rust dissolvers and lubricants, which has a high penetrating effect due to its low surface tension and is good for dissolving tightly seized parts in the inaccessible places. It is made by Wynns, and although I have not personally used this product, it does get good reviews.

Unfortunately, as you have found, a paper manual is not available for the Range Rover Sport. Haynes do supply information for your vehicle on an ondemand basis, but this is only available on the internet at