Overheating Disco 300tdi

Driving back from work today and the bloody thing started to steam just as I got to my house, when I opened the bonnet I found the plug on the thermostat housing had broken off and the water was ****ing out!
I got a new plug (brass this time) put it in and it has overheated again
Anyone got any ideas why?

Also went to change the thermostat and one of the bolts rounded straight away great! Just about sums up my ****e day:doh:

Cheers for any help Greg

There are a number of things to consider;
1. did you bleed the system to remove all air after replacing the plug
2. is there still a leak in the system
3. is the pressure cap defective
4. how long did you drive with the engine overheating
If you overheated the engine you may have blown the head gasket. Is there water in the oil. Check out the other threads on head gasket failure.
The thermostat housing bolts can corrode. I always use hex flank drive sockets on these but even then they can shear off. Always refit with copper ease grease.

Greg Part said:

Driving back from work today and the bloody thing started to steam just as I got to my house, when I opened the bonnet I found the plug on the thermostat housing had broken off and the water was ****ing out!
I got a new plug (brass this time) put it in and it has overheated again
Anyone got any ideas why?

Also went to change the thermostat and one of the bolts rounded straight away great! Just about sums up my ****e day:doh:

Cheers for any help Greg

Click to expand...

When you put the new plug in, did you refill the system with coolant? Did you bleed all air out of the system?

I wonder what made the plastic plug blow in the first place - too much pressure in the cooling system?

Cheers
Dave

filled it up again through the two plugs and also one pipe on the heater matrix, and still pressure in the pipes when run up. The thermostat is being changed tomorrow, but looks like the head gasket is the problem?
Cheers for your replys Greg