3-Series (E46, E90)Chat relating to the BMW 3-Series from 1999 to Current. Models include: BMW 316i, BMW 318i, BMW 318Ci, BMW 320i, BMW 323i, BMW 325i, BMW 330i, BMW 328 Ci, BMW 328i, BMW 325i/xi, BMW 330Ci, BMW 320d, BMW 330d, BMW 335d.
I just recently bought my 330i with 165k miles and am planning to replace all the coolant components. I have not started yet but my coolant level light is comming on as of today at cold start up. I plan to check the level of the expansion tank in the morning. Assuming I find that the cold level is low, I don't really know what type of fluid is required. Is it super critical what type is used? Is is a 100% fill or do you ever mix fluid and water? Any assistance is appreciated.
I personally recommend the BMW blue coolant. It was specifically designed for our cooling systems. When topping off its recommended you stick with what you already have in the car. If you need to top off that's fine. When refilling the system make sure you use a 50/50 mixture.
It is not advisable to mix different types of coolant, as many are not compatible with one another. To eliminate guesswork, and possible coolant related issues, it's advisable to only use BMW coolant in the car.
Many people use a surfactant or wetting agent in their cooling systems such as Redline Water wetter or Royal Purple's Purple Ice to aid in cooling system efficiency. These products are guranteed to be compatible with all types of coolant and will not cause damage to your cooling system.
What brands or types to use:
See above. BMW coolant is recommend for all applications. It should be mixed with distilled water (not tap water) in roughly a 50/50 ratio.
How often should you change it:
The BMW-recommended service interval for coolant replacement is every 20,000 miles. It is advisable that you change your coolant at least as often as this to protect against internal corrosion.
How much do you need and how hard is it to change:
The cooling system capacity for E36 M3's is 11.4 quarts (2.85 gal), 50/50 water/coolant. This equates to roughly 1.4 gallons of each. You'll need to buy 2 gallons of BMW coolant and 2 gallons of distilled water to fill the entire system.
The cooling system is drained through a radiator drain plug, and a plug in the engine block. I can tell you from experience, the coolant flows out of the block with a fair amount of fury behind it. Plan on a decent sized bucket, or a decent sized mess. Bleeding the system is imperative when done refilling it. This is done by running the car with the cooling system topped off, the radiator expansion cap off, and the bleeder screw open to expel any air in the system.
It's a big mark up. A jug of Zerex GL-05 here is $17. The BMW 4L jug is $34. Sadly you need two jugs as you need 10 Litres (E36 anyway). Flush the system out with distillers water. Regular tap water is too hard and leaves bad minerals you don't want in the system. Always distiled water. I get jugs at Walmart for $1 each.
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