Renault Midliner

Yes there is a solenoid that stops the key from turning when the engine is running.. this is indeed done via the oil pressure... a right royal pain in the arse when it the engine stalls out on a freezing morning.. and the oil is thick and holds the pressure up for a minute or 2.. thus locking the key in place untill the pressure drops and releases it.

As to fixing it.. unfortunately when the solenoid failed on our truck, the person trying to start it wrenched the key round with a pair of pliers.. snapping it off in the lock as you'd expect, so i just fitted a new ignition barrel and key in a different place on the dash, and swapped the wires over from the old switch.

Best thing to do is take the barrel out and find the solenoid, and see if applying power to the solenoid releases the key, i never looked at it that much.. it could well be a mechanical interlock with an oil line to the barrell.. you know how the french are at making quirky things :)

Thanks for the info. I did come close to using a pair of plier but I thought better of it. I think I will have to look at the wiring and see if the solenoid is still working. Something nice to do on a cold winter morning! Thanks once again.