850 T5 coolant level rising and falling

[cheshired5]

Originally Posted by martin_r_smith

Is your expansion tank can faulty I wonder? If it isn't letting out the pressure correctly the level in the tank can rise and fall.

Good point.
Flipping the cap seal could be a nice cheap try or just a new cap.

[Bigfella666]

Thanks chaps !

Got permission from Lakes to tread on their yard 2morrow and retrieve a coolant bottle after I drop family in Rutland but will flip cap seal in any event.

On the face It the ol girl is not overheating at any point. Anybody have a view A if problem persists how long coolant bottle is likely to last before it splits and how many I should keep in boot !!!!!!

Could problem be linked in any way to defective coolant stat ?????

[martin_r_smith]

I think the cap is your problem all the other symptoms seem pretty normal to me. It is a pressurised system so running it without the cap on will allow the coolant to rise. If the cap is defunct then it will not be regulating the pressure and cause over pressurisation of the system which can also raise or lower the level in the expansion tank. New caps are not expensive and we'll worth ruling out.

Also what colour is your cap? If grey it should have been changed for a green one a long time ago, these are well known to fail.

[Bigfella666]

Martin

Many thanks, cap is grey, done 160k. It is an odd feeling, having spent prob 2 days monitoring things, trying to resolve etc yet still preying you are right !

[V70Zig]

Fisherman ha ha, casting everywhere and coming up zilch. All started with coolant loss after Christmas and can't find a leak anywhere.
Cast your hands under that carp-et ha ha, at least that'll rule out the heater matrix.


Just seen you have the grey cap......get a green one....but still check under them carpets,

[kevvydude]

have you checked the bottom right side of the rad for weeping, as they are renowned for the alloy detatching from the plastic outer and weeping , but no water on drive,as it blows the water while driving and under pressure. so not visable leak

[Bigfella666]

Kev
If leak there not convinced hat would cause rising and falling level but happy to be persuaded.

Chaps, flipped seal on Sunday no diff, rise and fall the same. Stopped at lakes autos and removed 2 bottles, changed cap ( both regrets are grey ) but noticed some improvement when opened hood 70 miles later. Green cap on order from Super Steve at Braydons, will keep you posted. Fingers still crossed and holding length 4 X 2 for 2 weeks now !

[Bigfella666]

Otherwise I shall be left with placing old cap back on into which I have drilled a 0.5mm hole, I shan't repeat who gave me this advice but he says it has been known to work and is a little known trade secret if your head is failing !!!,

[Tetleysmooth]

Airlock?

[kevvydude]

Originally Posted by Bigfella666

Kev
If leak there not convinced hat would cause rising and falling level but happy to be persuaded.

Chaps, flipped seal on Sunday no diff, rise and fall the same. Stopped at lakes autos and removed 2 bottles, changed cap ( both regrets are grey ) but noticed some improvement when opened hood 70 miles later. Green cap on order from Super Steve at Braydons, will keep you posted. Fingers still crossed and holding length 4 X 2 for 2 weeks now !

if the rad is weeping then it will introduce air into the system, do you not see any dried antifreeze around pipes ect.