Help! It's Not My Head Gasket Gone Is It?

I'm praying it's not a head gasket and it's just a water pump, but my disco (1995 300tdi) started doing this today.

On a 125 mile drive from Coventry to Skegness, about 60 mile into the journey, I pulled in for a toilet stop (I was with 3 of my young kids, 2 of them disabled with learning difficultes, one ten, one 8 and on 4 yr old). Everything was fine before we stopped. We pulled away and temp gauge went straight up within 5 miles it was just below the red mark, and the heaters were blowing icicles out, and I pulled over, it cooled down straight away (within 4 mins it was normal temp again), whilst ticking over, once temp was normal, I switched off and restarted to try and jolt the thermostat, as I thought that was the problem. Sure enough, heat came through nice, I drove off. Within 2 miles the heaters were cold again, and the temp gauge was back up. Pulled over and called RAC. The guy *eventually turned up, took out the thermostat, we drove to the next layby 2 miles up the road, and the temp was back up, blowers cold. The thermostat was moving freely, and appears to be 100% fine.

So from that description can anyone point me in the direction I should be looking, head gasket, water pump, or other?

Thanks very much.

* It took the RAC from 7pm until 10.40pm to get a tow truck out to us, we eventually got home at 12.30am.... Not pleased with the RAC, apparently the nearest tow truck was 45 miles away lol... /mini vent over heh
oh and for once the kids were spot on, didn't moan too much, even though it was cold, and boring. To top it off the mrs had a beer ready for me when I got back... all ended ok I suppose....:blabla:

heaters blow cold if sysyem is short of coolant ,which could be many reasons incuding head gasket ,was this he first long journey for a while because its possible coolant lost over long period but wouldnt show on short journeys,likewise thermo
stat needs full system to operate properly ,undo 2 x bungs one on rad rh side one on thermostat housing and fill system till over flowing then test car,also run hand over rad to make sure its cooling over its whole surface and not just hot on top hose side expansion bottle level is not necessaryley level in engine check this first as it is vewry common,you can check thermostat function by feeling top hose it will be cold till thermostat opens,if after all that it still pressurises with good rad hot all across and full system check head gasket ,quite a simple job on a 300tdi head gasket about £10

jamesmartin said:

undo 2 x bungs one on rad rh side one on thermostat housing and fill system till over flowing

Click to expand...

do NOT undo bungs - REPLACE them with brass fittings, as they are likely to break. Make sure yu have replacements at hand. Any probs obtaining them - PM me.

Cheers guys.. I changed the water pump, and that seemed to fix it, the heaters were back to better than normal, blowing warm even before the gauge moved, and the gauge sat where it normally sat. I drove it round for a few days last week, then took her on a drive today, got 65miles into the journey, the blowers cooled a bit, and the gauge started creeping up, I pulled over and checked the water, and it was all gone from the expansion tank, luckily I got a kettle of hot water from a local shopkeeper, topped it off, got a spare bottle of water, and headed off, everything returned to normal.

About 40 miles later, all was still normal, but as I was coming onto a motorway, pulled over to check the water, and it had almost all gone from the tank again... I'd been clever and put the spare water on the dashboard over the windscreen blowers, (getting it piping hot, believe it or not!), so I topped it up and carried on the final 30 miles with no bother.

There's no water leaks fro anywhere, but when I opened the expansion tank with the engine hot, I noticed there was two small puffs of steam come from the centre rear of the radiator. I've been told that openeing the expansion tank on a hot engine with a blown head gasket, can blow lots more steam than normal out the cap, and mine does not do this.

I hope all this info can help someone narrow this down for me, as I'm not a rich bloke, and can't afford to keep going back and forth to a garage to do this...

On the plus side, she passed the MOT straight thru, today, so not all bad news...

dont think steam from rad might be your fault unless rad is in good condition and cooling over all of it yoiu will eventually get blown head gasket ,head gasket failure is usually a sign of a fault in cooling system ,lack of coolant,broken pump,poor rad efficency ,leak like you etc,and fill with bungs removed get brass ones if possible,replacing each bung as it overflows expansion tank level ius no indicartor of system level, the amount of steam coming out of cap when pressure released depends on temp ,blown head gasket will over pressurise system allowing coolant to be blown out of cap, heater blowing cooler is usually a sign of coolant loss