I have a Disco II V8 with LPG conversion using Romano Direct injection system. During standard service noticed coolant loss and block test failed. The car is under warranty so they went and diagnosed a cylinder head gasket problem and fitted new gaskets and skimmed heads. On return the car continued to run poorly on LPG with a clear misfire and still some coolant loss although less. I took the car back to the LPG installer to check out the system in case the Land Rover dealer had put it back incorrectly. On testing Cylinder 4 was misfiring permanently but only on LPG. Changed all LPG components and plugs leads etc and still same problem. I was convinced that it was not an LPG problem. So back to the Land Rover dealer as a distinct tapping has now started, only on LPG. The tapping starts when car goes to LPG when warm and increases with more revs. The dealer has now stripped the engine and there system is reporting misfires on most cylinders on LPG but nothing on petrol. The dealer is trying to tell me that the problem is that the LPG has been cross wired to the Lambda. This does not explain coolant loss or the tapping and I had covered over 20,000 miles on LPGG prior to this problem. The bottom line is they want to charge me £1000 for stripping the engine and putting back together as the warranty people say there is not a problem. I believe I have a lose liner and potential crack in the block. I would have to prove this and incur another £1000 expense if I am wrong, using a hot pressure test. Why would they symptoms only appear on LPG and not petrol?. With these types of symptoms do you think I have a high probability of proving a lose liner or crack block or do I have another problem and should I cut my loses?
Many thanks for any help.