How can I add an auxillary input to my 02 BMW 325i?

How do I add coolant to a 2004 BMW 325i sedan?

• My coolant light is going off. I know where the cooling system cap is located under the hood but how do I add coolant to my car? Do I need to drain anything or is it simply open the cap and add the necessary amount of coolant it needs?? Also which is the best coolant to buy for a BMW 3 series. I know nothing on how to perform routine maintenance but it looks like I can handle this one myself. I also use synthetic oil on my car if that means anything to determine what coolant to use. THANKS!!!

• Answer:

  you know its been awhile since I was under the hood of a bmw but there should be a plastic resivour next to the radiator cap. This is an overflow, what happens is as your car warms up, coolant expands and goes in the overffow, when it cools off, coolant is sucked back in until radiator is full. Look inside the plastic resiviour there is a line for fluid on the side for cold fill it with coolant or distilled water (in a pinch use tap water) up to the line. drive the vehicle until its warmed up and then park, as the radiator cools it should draw in the coolant. If you are loosing coolant regularly, there may be an issue with a waterpump or something. keep an eye on it, its normal to lose some coolant, but not like a quart or more a month. Its also a good idea to replace the radiator cap once in a while. since this is an 04 its likely ok for a few more years.