Quote:
Originally Posted by Roler
We're digressing a bit from the thread, but I agree with JJ....my temps actually came down with diluting my 50/50 coolant mix...
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The higher the ratio of water the cooler it will run, as you increase the "coolant" you reduce the capacity and rate the liquid can absorb heat, the only issue is the less "coolant" the lower the boiling point is. The reason we put "coolant" into the water is to raise the boiling point (not that is does much for this), lower the freezing point, reduce corrosion from the water and to stop stuff growing in it.
Straight deionized/distilled water is best for cooling, go to 30% coolant mix and drop about 15% of cooling capability, at 50% you can drop nearly 40%. In hot climates (like the upper 1/3 of Australia) you should not be using over 35% coolant ratio (20-25% is ideal) as the air temp is much hotter making it much harder to get rid of the heat via the radiator making it far more important to have the capacity in the coolant, down side to this is you need to check/change your coolant a little more often.
You can also go to waterless coolant, this is not as good as pure water for cooling in a lot of areas but has some great gains. Firstly you never have to change the coolant again, it won't expand with heat and it's boiling/freezing point is so much higher than traditional coolant, these 2 things means you can open the radiator cap even when the engine is baking hot. Now it is not as good as water for picking up the heat but is better at getting rid of it at the radiator and it can absorb more of it for each 1 degrees of temp it gains, it also won't suffer from localised boil spots (this regularly happens when you go smashing up the soft sand on the beach, you get small boil spots inside the block with standard coolant). Many people (including myself) report better cooling when they go to waterless coolant after they have had everything scrubber, cleaned, flushed and done the pre-waterless coolant run then gone to the waterless coolant. This is because the inside of the block has had the scale and corrosion removed through this process and it won't form again meaning better transfer of heat from block to coolant leaving you with better cooling.
Also worth noting that even though your engine temp might be the same say for no coolant/30%/50%/waterless it certainly does not mean the bore temp is the same, straight water gives the lowest bore temp out of the liquids discussed here but you can make it lower again by adding a wetting agent (which can reduce bore temps by as much as 10%), waterless comes in at close second here as it has "wetting" properties that act very similar to pure water with a wetting agent. A 50% coolant mix will raise the bore temp by around 5% which is not that much unless you are in a hot climate as it adds to the other factors already reducing your overall cooling and is one area that is typically not known/thought about, much harder to measure but is far more important than the overall engine/coolant temp.
