Thread: Blown expansion tank again

Out of curiosity when was the last time you had the radiator/cooling system flushed?

And how old is the Thermostat?

I installed one from a Volvo 144 on my County in lieu of the black painted steel one. The Volvo tank is white plastic, cylindrical and seamless. You can see the water level through it. PM me with your e-mail address if you want a photo.

Originally Posted by Rovernaut

Would have thought the cap would have release the excess pressure before the tank blew?
Any one else had this problem?

Hi Rovernaut, not sure what car you have, but I read somewhere that this is quite a common problem, particularly on the 4.6 P38 RR's.

On the RR, it's common for the coolant to come out under pressure from the split expansion tank and then ruin the fuse box in the process.

Like you, I would also have thought that the cap would release before splitting the expansion tank, but maybe the tanks degrade with age?

Jon

There are 2 tiny valves in the cap ie. one to let air in on cooldown & one to vent any normal HP. I can't recall the release pressure, but it's stamped inside the cap.

When was the last time you cleaned & sprayed some silicone spray into them & physically operated them to see if they move?

Are you overfilling the coolant level?

Hi Rovernaut, I replaced my black one with a new white one a few months ago on my Disco as a result of reading a similar thread on here (and also the fact that my tank was suffering from significant degradation of the surface on the centre front top edge). I spoke to a couple of reputable Land Rover parts suppliers here in Adelaide at the time and they pretty firmly shot down the suggestion that the white ones were inherently better than the black ones.

The consensus is that, black or white, they're only good for 150,000Km to 200,000Km and then you throw them away and buy a replacement. Fortunately they're not too expensive. I guess we just need to start viewing them as a consumable like a serpentine belt, or radiator hose (unless you're prepared to go down the modification path like Brian Hjelm. It’s a throw-away world!

Out of interest, did you have a low coolant alarm fitted to warn you this time (and did it work) or was it the temperature gauge that gave you the early warning?

Originally Posted by Brian Hjelm

I installed one from a Volvo 144 on my County in lieu of the black painted steel one. The Volvo tank is white plastic, cylindrical and seamless. You can see the water level through it. PM me with your e-mail address if you want a photo.

Hey i have stacks of them...
Thats a great idea...

The Volvo 240 one is also white and semi transparent.. it pancake design and about 3" high with a bottom hose and top breather.....

The 1st pic has a Volvo 740 and 940 Expansion tank... the rounder one


Last pic is one from a 240 series volvo, lower profile flat tank... every wrecker in the world has a old 240 laying around.....
in all the years i have had volvo's i have only blown one tank... and that was due to a blown head gasket...

Originally Posted by tombraider

Out of curiosity when was the last time you had the radiator/cooling system flushed?

And how old is the Thermostat?

the thermostat is new only 2 months old.
the system was flushed probably 6 months ago
the temp gauge only got to just over 1/2 way

Originally Posted by 4bee

There are 2 tiny valves in the cap ie. one to let air in on cooldown & one to vent any normal HP. I can't recall the release pressure, but it's stamped inside the cap.

When was the last time you cleaned & sprayed some silicone spray into them & physically operated them to see if they move?

Are you overfilling the coolant level?

no level always to the 'X' inside tank.
Never cleaned the inside of the plastic pressure cap