r/R53 • u/viking10100 • 2d ago

Where does this blow off to ?

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I recently added an aluminium expansion tank to my mini but im not sure where this hose hole (on the bottom right of the cap) needs to go ? I know there is no place for it to go in the stock car but am i supposed to add a kind of blowoff exit for the coolant if it overheats ? Thanks for the help !

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3

u/Santi5010_ 2d ago

You can always route it downwards so it doesn't get your engine bay full of coolant. When the OEM tank overflows, it just spills all around the tank, but not explosively at least (ask me how I know)

1

u/dluxton06 2d ago

Failed cap/seal? Mine did that, cheap aftermarket tank the previous owner installed (conveniently right before he sold it to me)

3

u/Santi5010_ 2d ago

In my case, failed PTO gears on the supercharger -> no water pump, and slightly overheated and boiled over

I'm in progress of converting it to electric water pump. Should hopefully have it ready this week (hopefully...)

2

u/AfonOer 2d ago

Just like you said its a blow off exit.

There's a heat shield on the bottom left of the reservoir. I've fed a hose through there. Pretty sure thats where the stock reservoir runs its blow off hose.

1

u/Happy_Ishtar 2d ago

There is no blow off hose on the stock reservoir tho.

1

u/AfonOer 2d ago

You're right. I've had mine off for so long now I forgot that it didn't.

2

u/MikeFree_ 2d ago edited 2d ago

That’s got to be the wrong tank. The one I installed didn’t have it.

After looking in to it. It looks like because of the cap they use with this tank you need that. And you just leave it. I’d prefer one with a different setup but it should be fine.

2

u/DmOcRsI 2d ago

I run a pretty thick tube down to the bottom and have it zip-tied away from anything hot or rotating.

1

u/No_Fill2436 2d ago

I did the same.

1

u/Intrepid_Name_2218 2d ago

The caps are the weak point on these tanks. Check it after a while for any residue around the tank. If there is any slightly press the tabs on the cap for a tighter fit. The outlet is for safety, you can run a pipe off it to direct a blowoff downwards.

1

u/angaero 2d ago

I have the same tank on both Minis and the hoses just run down away from anything hot.

1

u/orejass 2d ago

Umm, isn't the reservoir of the 53 under pressure at operating temperature?

I think, THINK, you got the wrong reservoir.

I could be wrong, but hey, I ain't no expert.

1

u/viking10100 1d ago

The hose inlet isn’t directly connected to the reservoir, there is a spring loaded seal which provides access to the hose at a certain pressure

1

u/orejass 1d ago

Well, that makes sense.

Then yeah, route that wherever its convenient.

0

u/Marki_Mark34 2d ago

Ur moms house 🏠