It lowers the freezing point and thereby protects against cold weather. It
increases the boiling point and thereby allows the engine to run hotter
(which has an effect on emissions).
A small deficiency of antifreeze in the coolant is inconsequential.
Same here. I usually change it every 2 years and it still looks like
the day I put it in. I feel it is overkill but coolant is cheap and it
is usually very easy to change. This is the regular green stuff. Haven
not changed the BMW coolant out but it is on my list of todo.
I've seen what neglect can do as well. Clogged radiators, cracked
You obviously don't know what the hell you are talking about.
Adding antifreeze (aka coolant) reduces the mixture's ability to carry
away heat as compared to plain water a small amount. However, the
coolant mixture can be brought to a higher temperature before it will
That does not mean the engine will be hotter, that is controlled by the
thermostat (not the ECU). But if any part of the engine cooling system
happens to get above 212F plain water will vaporize, and water vapor
does a *really* bad job of cooling. The recomended 50% mix of BMW
coolant (Glysantin G-48) will raise the boiling point to 265F.
Consider that when you have a 195 degree thermostat, that is the
temperature that the "stat" tries to regulate the coolant at. Since the
coolant will always be a little cooler than the average engine
temperature we can assume that there will be spots in the engine that
will be marginally hotter and cooler than the average. So any one spot
inside the engine only needs to be 7 degrees hotter than the average and
poof! Boiling starts. Once you get vapor bubbles in the coolant it's
ability to cool decreases rapidly and the heat will run-away and you
soon have a boil-over.
So yes, using a coolant mix is important. Otherwise you should run a
much lower temp t-stat (175-180F)
It increases the boiling point and thereby allows the engine to run
The engine does not run hotter with coolant. That's crap
Your statement implies that your engine management system analyses the
content of the coolant - it does not.
The engine does not boil with plain water unless there is a fault. It
certainly does not alter its running temperature when coolant is included.
I am also unconvinced hotter engines are better on emissions - please
The main difference between US and EU emissions standards
are centered the engine warmup period. In the US, the period
allowed for higher emissions just after starting a cold engine is
much shorter than the EU standard. This means that the catalytic
converter is located closer to the manifold and that we have an
air pump to add air to the exhaust stream to provide a quicker
light-off of the converter.
A hotter-running engine is not necessarily better for emissions
(after all, that generally increases NOx emissions - ala diesels),
however, it does increase the EFFICIENCY (simple thermo-
dynamics) of the engine, and allow better catalyst performance.
Both of those lead (indirectly) to lower emissions.
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