Technical Coolant woes on 2013 Supersport

[brokencr0ss]

Not sure if anyone has had this issue but here it goes.

I've noticed everytime the coolant reservoir is topped up to MAX, it always ends up overflowing some coolant through the cap, resulting in red residue all over the expansion tank.

So it ends up overflowing tiny amounts of coolant every trip till it reaches the MIN and stabilizes.
No issues with temps, never exceeding 90ºC or anything that hints to a blown HG. No milkshake in the oil cap, no oil residue in the expansion tank, no white smoke from the exhaust, no bubbling in the expansion tank whilst idling, the hoses never get rock hard and the system depressurizes naturally as the engine cools down... Nothing at all.
I'm all out of ideas.

I've replaced the cap when it first happened, almost 2 years ago and forgot about it, since it always ran on MIN without spilling anything after that.

The issue reappeared as of lately since it blew an IC hose and the dealership kindly topped up the reservoir.

I'm thinking I'll need to get a compression check on the engine and maybe a pressure test on the cooling system.

Any ideas?

 

[Officina red]

Can’t help you, but my Mini Cooper is exactly the same, coolant is always on minimum, runs flawlessly no problems at all, but top it up to max, go for a drive let it cool then check it, back on minimum, tried topping it several times, always back on minimum, so gave up trying and left it on minimum, been like that from new.

 

[varesecrazy]

Not sure if anyone has had this issue but here it goes.

I've noticed everytime the coolant reservoir is topped up to MAX, it always ends up overflowing some coolant through the cap, resulting in red residue all over the expansion tank.

I'm thinking I'll need to get a compression check on the engine and maybe a pressure test on the cooling system.

Any ideas?

Getting the coolant reservoir 'sniffed' for exhaust gases should do the trick

Remember that Multiair systems can give odd 'compression test' results too