9 replies to this topic

[bangermadness08]

evening folks, 

 

my overflow tank has decided it doesn't want to hold water, and now resembles a colander with the amount of holes it has.

 

Ive read of various forum postings that if you fully remove the tank and ran a overflow pipe from rad to the ground, you'll need to change the rads pressure cap. 

 

am I right in thinking this will be a basic 15lbs cap, as I've seen there is multiple 15lbs.

 

I know you can get replacement tanks from mini Japan, but my pockets aren't that deep enough.

 

mini is a 95 spa auto!

 

Thanks :)

[Steam]

You do not specifically need to change the rad cap, it will function correctly as it is, also you do not need to remove the overflow tank.
The only difference is you will be running the rad with slightly less water and do not top up all the way but just ensure the cores are covered by 1/2 inch or so of coolant.
One thing that needs to be checked is the thermostat as overflow bottles tend to disguise overheating so a lower tstat may be advisable, an 82C will work fine.

[Pops_Guild]

An SPi setup using Rover MEMS ECU needs a 88C thermostat. If any other thermostat is used then the cooling system will not work as the ECU is expecting and that will mess up fueling because the ECU needs the cooling system to get to 88C.

 

Same for the expansion tank (its not an overflow). It plays a part in making the cooling system work more efficiently. It'll work without it of course but it was put there for a reason...new ones are pricey though!

[hungdynasty]

evening folks, 

 

my overflow tank has decided it doesn't want to hold water, and now resembles a colander with the amount of holes it has.

 

Ive read of various forum postings that if you fully remove the tank and ran a overflow pipe from rad to the ground, you'll need to change the rads pressure cap. 

 

am I right in thinking this will be a basic 15lbs cap, as I've seen there is multiple 15lbs.

 

I know you can get replacement tanks from mini Japan, but my pockets aren't that deep enough.

 

mini is a 95 spa auto!

 

Thanks :)

My set up for your reference. Buy a sport water bottle, with height less than 20cm and use ziptie or hose clamp to fix it behind the grille on the center pole. I use a 7.5mm inner diameter transparent silicon hose so I can see if the coolant got suck back to radiator when cool down.

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[bangermadness08]

That’s a good idea I’ve been hunting around for universal tank but it’s always the unusual that works the best

[bangermadness08]

An SPi setup using Rover MEMS ECU needs a 88C thermostat. If any other thermostat is used then the cooling system will not work as the ECU is expecting and that will mess up fueling because the ECU needs the cooling system to get to 88C.

Same for the expansion tank (its not an overflow). It plays a part in making the cooling system work more efficiently. It'll work without it of course but it was put there for a reason...new ones are pricey though!

Thanks, I’ll get a 88c stat on the order as I can’t remember if I have one in there’re of that reading.

Also do you have to put coolant into the expansion tank, silly question I know

[Pops_Guild]

No probs. Yes the expansion tank needs to be around half full to work as it should, which is a tad tricky to do.

[MikeRotherham]

Is the SPI type expansion tank pressurised or not?

 

Judging by the poorly fitting insubstantial plastic bung that is jammed into the top I'd say it isn't.

Edited by MikeRotherham, 04 January 2023 - 10:45 AM.

[hungdynasty]

Is the SPI type expansion tank pressurised or not?

 

Judging by the poorly fitting insubstantial plastic bung that is jammed into the top I'd say it isn't.

No it isn't, it has a breathe hole at the top.

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[Pops_Guild]

From the factory they were air tight and held pressure, it’s just after 25ish years they degrade and leak from that “bung” and from the rivets that hold the bracket on. Just like a lot of the other parts on the SPi. I have a new one from Japan, it holds pressure.