Coolant light is on.

Coolant light is on. Do I have to pour out all the old coolant before fill in new one? What kind of coolant can I use besides the BMW branded one?

Thank you!

Coolant light is prolly on because of coolant level sensor. But because I have no idea what year, or type of E30 you have I cannot help any further.

Unless you know it is low phosphate stick to genuine. As a guide, low phosphate in other brands is the same price as genuine.

if its green use green.

but if its low i would find where its going first. you could potentially have a major problem

ya im guessing it to be the sensor also the sensor is an easy replacement and the part isnt expensive depending on your cars year and model mine cost about 30 bucks if i remember correctly and took me ten minutes to replace light went away id go with the sensor first because ur going to need to replace it anyways

Depending on your E30 (318 or 325e/i), BMW used one of three coolant reservoirs. In most cases, the main culprit is the level sensor. On BMWs with reservoirs mounted on the left or right wheel wells, BMW used a two wire sensor. If the reservoir is full and coolant low light is on, remove the level sensor connector and use a small piece of wire to connect between the terminals. If the light goes off the wiring is good, but the sensor is bad. For your question of what type of coolant to use. The main concern is that what ever brand you use (BMW, Everex, Peak, Prestone, etc), it MUST be phosphate free. This is a must because of the engine's cast iron block, aluminum heads, and the radiator's plastic/aluminum makeup. Today, most major brands are phosphate free and able to mix with other brands.

Big Boyz with Bad Toyz