Coolant reservoir melted/exploded!

[t25blue]

Hi, i've got a 1984 T25 autosleeper watercooled, went out to start her up this morning, started fine,everything seemed ok so i left her running for a while, next thing i hear a loud bang come from the bus,steam pouring out of the inside from the engine bay and coolant all over the floor, she`d blown the hoses off the coolant res and got so hot/pressurised it blew a hole in the bottom of the res. Also broke the plug off from the distributor to the starter motor when the explosion happened. Think it must be thermostat trouble,but any ideas????

[Mocki]

im assuming you left it running a goodly while then?

you are on the old baynet pressure cap? early water system..
if you are lucky its the cap at fault, but could be a head issue, exhaust gasses pressurising the system?

im not far from you if you need help, but i work weird hours ..... i may have a old style header tank in my stores, but i cant remember if i already let someone have it before. id need to look....

[t25blue]

The old baynet pressure cap?? could you elaborate?

[Mocki]

do you unscrew the pressure cap anticlockwise 5 or six turns, or 1/2 a turn and lift?

the newer (late) water systems have a blue (sometimes black) screw off cap, with a pipe outlet to the top up tank, the early ones have a baynet cap, like a conventional car radiator cap from some years ago

[Bowton Lad]

Assuming it's a 1.9 DG fitted to t25blue's 1984 van, it should have the later screw cap. He hasn't actually stated what engine is fitted to his van.

[Mocki]

Assuming it's a 1.9 DG fitted to t25blue's 1984 van, it should have the later screw cap. He hasn't actually stated what engine is fitted to his van.

as it happens it has got the darlek type, but it SHOULD have a bayonet type, being pre'85 .
82-85 early

[Bowton Lad]

Assuming it's a 1.9 DG fitted to t25blue's 1984 van, it should have the later screw cap. He hasn't actually stated what engine is fitted to his van.

as it happens it has got the darlek type, but it SHOULD have a bayonet type, being pre'85 .
82-85 early

My van's registered January 1984 & it's got the Dalek type screw cap fitted.