E46Fanatics - View Single Post - E46 COOLING SYSTEM GUIDE - overheating/coolant/etc
View Single Post
Old 04-06-2012, 02:45 PM   #31
Blocked Out
Registered User
Join Date: Aug 2009
Location: Planet Earth
Posts: 5,498
My Ride: Imola 330i M-Sport
Originally Posted by E46Mango View Post
Awesome. Good stuff. Wasn't aware we could use the E30 cap. Are you using one? And if so, how long?
I have it for about 20k miles.
Originally Posted by ImolaSix View Post
Great write up Mango! Should definitely be stickied.

Btw there's a reason the cap is set for 200 kpa. Water under pressure will have a higher boiling point than water at normal atmospheric pressure. If you switch to a 140 kpa cap then you are lowering the efficiency of your cooling system.
True but the change isnt drastic to significantly reduce the efficiency but is big enough to reduce the pressure to prolong the life of ET.

Reason why I personally think E30s used a 1.4 bar cap is because back when E30s were made BMW didnt have the technology to make plastics (Expansion tank for the biggest part) withstand the pressure of a modern E46 cooling system which is 2.0 bar. E30s cooling systems are plenty efficient. E46s have a 2.0 bar system due to the fact that technology enables BMW to make ET with the plastic that can withstand the pressure, but as we clearly know E46s ET are cracking open all the time , its THE weakest point in the whole cooling system .

You do lower the boiling point of your cooling system but its still plenty enough to keep the car cool. The change isnt that significant to get scared off.

Its the same when using 50/50 mix of coolant. Its to raise the boiling point and, well mostly to prevent from freezing, but if your country never sees temp below freezing(and also not as hot as texas) you can drive on water only, sure the boiling point will be low but it'll never be significant enough.
Original BMW Teile ///

Original BMW Parts for Sale - DISA, MAF, SAP, Coils, much more PM ME
Blocked Out is offline   Reply With Quote