A customer brought in her 2.4 TDCi Defender 110 station wagon. She was very worried because it would suddenly lose power for 15-20 seconds then pick up and run normally: not a problem in the car park but frightening on the motorway. It was an intermittent occurrence, so hard to predict.
A diagnostic test revealed a new fuel pressure valve and switch were required. I fitted the new parts (£240); they made no difference. Another diagnostic test showed that it had the wrong injectors. I took it for a test run, with a passenger to keep an eye on the gauges. The problem occurred again and by the time I drove on to the hard shoulder it had cleared itself and was running normally.
My passenger noticed the temperature needle flew up the gauge then back to normal in about 20 seconds. While the needle was in the hot zone the engine dropped into limp home mode but didn’t leave a fault code for the diagnostic test to find.
I fitted a new thermostat and temperature sender switch and flushed the system. I took the 110 for a test drive… a clean run!
The fault had finally been traced and dealt with, much to the relief of the customer.
This workshop advice appeared in the Feb 2015 issue of LRO. Back issues are available to download on digital devices here.