This LRO reader emailed LRO.firstname.lastname@example.org to ask our experts about occasional starting problems with his Defender 110 Td5.
My 2004 Defender Td5 is properly looked-after and drives well. However, it does have an occasional starting problem. Ninetynine per cent of the time, it starts immediately. But for no apparent reason, on occasions the engine turns over but just won’t start. I’ve noticed that the temperature gauge goes into the red when this happens. In fact, I now look at the temperature gauge before I try to start the engine – if the needle’s in the red, I know the engine will turn but not fire. If I turn the ignition on and off a few times, the needle will go back to normal and then the engine starts normally.
I suspect the ignition switch may be a little worn. If the temperature sensor on the coolant were playing up, I would have thought the car would go into limp-home mode as I was driving along, but this only occurs when starting – either when the engine is hot or when it is cold.
Incidentally, I have repaired the solenoid on the starter motor with a kit – that solved the starter motor issue I was having about six months ago. But I don’t think this is the problem and in any case this wouldn’t show on the temperature gauge.
Peter Dunsmore, Norwich, Norfolk
If you hadn’t mentioned the temperature gauge, I would have said to check the injector harness for oil leakage. Take the cover off the ECU and look for oil at the connector. If you have any, replace the harness – it will cost around £50.
However, the temp gauge going to hot indicates you have a bad earth connection somewhere. Clearly this isn’t affecting the cranking, but most probably the fuel. You have two options: you could locate and clean any earth points you can locate in the engine compartment and under the dash (we’re talking black wires terminating at bolts on the bodywork); or you could obtain a 15ft length of wire, fit a crocodile clip at one end for the battery negative and a sharp probe (such as a syringe needle) at the other. When the fault occurs, stab any black wires you can find and watch the temperature gauge – if it goes back to normal, that means the black wire you stabbed isn’t earthed.
This workshop advice appeared in the January 2016 issue of LRO. Back issues are available to download on digital devices here.