Hi everyone Cosmo948 here. I joined this forum because I need some help so please bear with me. My daughter brought me a 97 landrover discovery turbo diesel manual for my birthday. I really love it although I was told there was a few issues. having sorted most of them out it,s been running good until recently.I found I had a cracked radiator and the coolant tank had also split. I have nor replaced the radiator. water pump, coolant tank, thermostat and all coolant pipes. flushed out heater core as well. put it all back together but now when I start it and run it for about 15 mins it gets over pressurized and coolant and a lot of air hisses out of the coolant tank. I,ve bled the system dozens of times yet still get the same issue. I,ve noticed that there is only one coolant pipe which goes from the radiator to the coolant tank and one which allows the coolant to flow back to radiator. On the thermostat housing I,ve noticed a outlet which has been blocked off but dont know where this would go to. one thing I have noticed is when I fill the radiator or the thermostat housing up to top them off the coolant always runs back into the coolant tank filling it up. I know that the tank should always be the full mark yet mine is always too full. I am really stumped would would really appreciate any advice. p.s previous owner had removed the coolant ppes which connect to the heater system and reconnected one of them directly to the head. not sure if this the my issue or what any ideas ???

 

Sounds like a bad head gasket, or a crack somewhere into one of the cylinders that is opening up when the motor gets warm. There are testers that will check for combustion gases in the coolant system, Pretty sure you can rent them from auto parts places too. Discovery's are known for leaking head gaskets n the gas motors, which are aluminum and overheating will make them warp. Not so sure about the turbo diesels.

 

you can purchase a exhaust gas test kit for your cooling system on amazon. they are not expensive and not 100% accurate but it is a start.