Thread: expansion tanks on disco 300tdi's

Hi
I am hoping that those of you that have had the unfortunate experience of an expansion tank failing could let us know roughly how many kms on the car when it went and what year model??

thanks
Lindsay

Hi Lindsay,

My Black Tank is still good at 160,000 kms.

I suspect that failures of the original are due to other factors like a head gasket going, overheating and consequential increased pressure...only a hunch. Therefore the tank is blamed (shoot the messenger)

I cooked my donk and after the rebuild the shop put a new cap on the expansion tank...maybe this is the problem...it is supposed to relieve excess pressure...so what if the cap fails...the tank bursts.

What Low level Alarm have you fitted?

i have a black tank at 211,000 and am in the process of fitting the EMS alarm setup you see advertised in the top banners. nice solution as it has extra temp sensor setup as well as float level... and yes i paid money for it as i think the idea is excellent...

I replaced my tank ('98 build, '99 delivery) over twelve months ago (roughly 150,000km) as it was splitting badly below the seam, just wasn't spitting water out yet. I've had no head gasket failures, no hose failures, no overheating in the time of my ownership (110,000km now) to suggest there was any other cause for this splitting.

The 'black tank bad, white tank good' was all over the Pom boards and I questioned it heavily, eg, "it's the same tank without any pigment", "you have other cooling issues", etc, etc, ............until mine split. I bought an OE one, fitted it and joined the chorus.

Originally posted by rick130
and joined the chorus.

brains, looks (look left ), cooks and he can sing too!

My black tank developed a leak at the midline join on the drivers side after about 220000 km. Replaced with the new white plastic ones and no problems. I suspected the 15 psi cap may have been building up to a higher pressure but there wasn't a great deal of pressure when hot.

Even when combined with the leaky P gasket the water level never got too low. Had all hoses and radiator replaced after run in with cow several years back.

My father in law would say its built in obsolescence in everything.

Question: If the tank cap psi is so low could the cooling system be run without a cap at all, to stop a pressurised leak if a split happened on a trip?

Originally posted by incisor+--><div class='quotetop'>QUOTE(incisor)</div><div class='quotemain'><!--QuoteBegin-rick130
and joined the chorus.

brains, looks (look left ), cooks and he can sing too![/b][/quote]

thanks Inc ! us fella's that live here in the hills are a handsome lot, and we pluck a mean Banjo, too.

if you do spring a leak on the road (or off) and it can't be repaired instantly, you usually set the cap so that it doesn't pressurise the system. The old style metal radiator caps were set at the first detent so that coolant didn't splirt out everywhere, but it didn't seal and pressurise the system. Not sure how you would do this with the plastic screw caps.