E46Fanatics - View Single Post - E46 COOLING SYSTEM GUIDE - overheating/coolant/etc
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Old 04-06-2012, 02:55 PM   #32
Mango's Avatar
Join Date: Mar 2006
Location: Southern California
Posts: 26,618
My Ride: Lexus
Originally Posted by Blocked Out View Post
I have it for about 20k miles.

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.
Great points. Personally I'll be sticking to the stock cap. But if the E30 cap works for you and provides the benefits you say, then that's great too. The way I see it, I'll be back in there replacing parts anyway at the 75k interval. Expansion tank is just $60 bucks anyway.
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