: 525i E34 cooling system

Rodrick Msuya
11-25-2008, 04:03 AM
I have been trying to understand how the Rad Cap works when the coolant is hot and the pressure has built up.
How does it release the pressure??

attack eagle
11-25-2008, 05:43 AM
the inside lets some coolant past it.that is if it is on the verge of blowing up or after shut off. under normal operating conditions nothing goes past it

Rodrick Msuya
11-26-2008, 03:46 AM
First of all, there are two things here, there is the coolant pressure that builds up when getting hot and air displacement from the expansion bank.
From the radiator to the expansion tank there is a bypass hall that returns coolant to the expansion bank. From what I have understood is that the rad cap will block the coolant from returning to the expansion bank building up pressure on the other end. The cap will realise the coolant/pressure on 200psi to the expansion and at the same time realise air outside from the bank so as to balance air and coolant pressure.

This is my theory; please correct me if I am wrong