3 replies to this topic

[ukcooper]

Hi all

Right then rad caps for the mpi, just bought a alloy header tank http://www.minispare...01240.aspx|Back to form minispares and it come with a 15lb cap and based on a metro version http://www.minispare...01240.aspx|Back but ive look in auto data, rover tec book and Haynes.

Haynes sais 1974 onwards 1.05 bar = 15lb

auto data said mpi 0.5 bar = 7lb

rover tec mpi said 0.5 bar = 7lb

auto data metro 1.3 said 1.05 bar = 15lb cap

So do you think I should be using a 7lb cap or not and what the difference between a 7lb cap and a 15lb cap as I don't know?.

cheers

[RooBoonix]

The one on my 1994 SPi is a 15lb cap if that helps :) It's just the pressure that the water can reach before the cap allows some water to go to the expansion tank/on the floor (depends on age of Mini whether fitted with an expansion tank or not).

 

I'd say that a 15lb cap should go on your car. I've looked on Autodata before the and information for the Mini doesn't seem particularly good...

 

Hope that helps,

Cam.

[Dan]

It's the pressure setting of the safety valve in the cap, which regulates the pressure the cooling system can be held at, which in turn regulates how hot the water can get without boiling. I find it very odd that the MPi pressure is listed as 7lb by Rover (you can ignore the Auto Data since they get the figure from Rover anyway) I suspect that may be a misprint and so maybe is why the current production caps are causing so many problems. Mini changed to 15lbs years ago and it made everything better. I guess you have to go by what Rover have written down but I'm very surprised it's that low.

[mini 4o]

Taken from 1997 rover workshop manual

manual covers changes to Mini models

manufactured from VIN SAXXNNAZEBD 134455

 

 

COOLING SYSTEM

Pressure cap opens . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5 bar

Thermostat starts to open . . . . . . . . . . . . . . . . . . . . . 88°C ± 2°

Thermostat fully open . . . . . . . . . . . . . . . . . . . . . . . . 100°C ± 2°

Cooling fan operation:

On . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105°C

Off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98°C