300 tdi disco auto 1996 engine

question for you not sure if anyone can answer but thought id as was on my way back down m25 today ive had no problems with the discovery up til now when the temp gauge suddly rose up towards the hot mark then dropped back down to normal then we got stuck in some traffic and as we pulled up to a crawl oil light came on then when moved off went out did the same again then we got moving and i was doing a steady 40 when she suddly stopped and not sure weather it was steam or oil smoke came from bonnet , then wouldnt restart had to get recovered home when back checked water which was low and oil was ok topped up watter and seems to run fine again although noticed plastic plug on top of thermostat housing had blown any ideas

sounds like yu overheated?? check head gasket

Sorry, but it sounds like th ehead gasket has blown or the head. It lost water and when this happens, the temp guage does go right up, then when it blows water out it goes back down to normal again (I have experienced it a couple of times). The oil light came on because the oil was hot and the engine was idling. Fill it with water to correct level, take expansion tank cap off and see if the level rises and rises and rises and then starts over flowing, if it does then its head off job

tried that trick and no the water is not surging when reving the engine landrover seems perfectly fine now filled it with water last night then did 20 miles or so in her with no problems just wondered if any one knew why she would suddly drop her water or get hot prob will have head off as a precaution

300tdi has pressure relief valve on cooling system back to tank-check it but expect head gasket

You need the sniff test to tell if the head gasket has gone & is the cooling side all ok fan ok? thermostat working? water pump ok?