Land Rover Repair: tdi overheating, coolant temperature, head gasket

Question
thank you in advance for any insight you maybe able to provide.1996 disco. tdi, auto. overheats quickly if throttle opened beyond half-way. uses water. no leaks. no bubbles, water surge, white smoke, to indicate head-gasket. if top plug on radiator removed, engine running, no surge or bubbles evident. overflow bottle operation, in/out normal. never boils, but runs high temp. indication on temp. gauge. no water in sump or on dipstick. power seems normal. will a radiator from '91 petrol disco ( 4 core) fit my vehicle ? can obtain new one cheaply. other than radiator fault/ thermostat fault/ water pump fault, any other suggestions, thank you. steve.

Answer
Hi Steve,

usual suspects you've mentioned but you forgot about the @&#@#*$#@ coolant temperature sensors. They can fail too!

I'd go with thermostat first, move on the rad then water pump.  I'd also find an independent rad shop and have them find you a rad.  Cost me about $500 installed for a rebuilt.  Well worth it. Extra core was a real bonus!!

Best of luck,

JohnMc