To give some context...
I realized this year that I cannot recall exactly when the coolant was changed last on my '98 BMW 328is. This spring it would occasionally start to overheat and I figured out the issue was down to the system being a bit low on coolant. At the time I added approx. 30-40oz (didn't seem like much) of some filtered tap water, bled the system, and it has been running great since.
I would like to get the old coolant / bit of tap water out of there before it is stored in an un-heated garage during the upcoming Michigan winter. The coolant visually appears fine and is a greenish-amber color. The car has always been serviced by the dealer, myself, or an indie shop that specializes in BMWs so even if it isn't the OE blue coolant I am assuming it was something that met similar specs.
Other than being a bit low earlier I haven't experienced any coolant-related issues.
My plan is to....
just drain the radiator, refill, and bleed the system. I figured this might be the safest bet to not "shock" the system and a full flush might not be necessary since I'm not trying to "fix" anything. Next spring I would do a greater overhaul replacing the expansion tank and coolant hoses and then refill with more fresh coolant.
Am I wrong in this approach? What coolant would be best, especially since it will have to mix with whatever doesn't drain out of the block / heater core? I am leaning towards the BMW blue stuff, but it looks like Zerex G-05 is recommended on some forums for BMWs. I would be open to the Zerex and any other aftermarket options if there's a compelling reason to use it instead (like it might play nicer with mixing).
I realized this year that I cannot recall exactly when the coolant was changed last on my '98 BMW 328is. This spring it would occasionally start to overheat and I figured out the issue was down to the system being a bit low on coolant. At the time I added approx. 30-40oz (didn't seem like much) of some filtered tap water, bled the system, and it has been running great since.
I would like to get the old coolant / bit of tap water out of there before it is stored in an un-heated garage during the upcoming Michigan winter. The coolant visually appears fine and is a greenish-amber color. The car has always been serviced by the dealer, myself, or an indie shop that specializes in BMWs so even if it isn't the OE blue coolant I am assuming it was something that met similar specs.
Other than being a bit low earlier I haven't experienced any coolant-related issues.
My plan is to....
just drain the radiator, refill, and bleed the system. I figured this might be the safest bet to not "shock" the system and a full flush might not be necessary since I'm not trying to "fix" anything. Next spring I would do a greater overhaul replacing the expansion tank and coolant hoses and then refill with more fresh coolant.
Am I wrong in this approach? What coolant would be best, especially since it will have to mix with whatever doesn't drain out of the block / heater core? I am leaning towards the BMW blue stuff, but it looks like Zerex G-05 is recommended on some forums for BMWs. I would be open to the Zerex and any other aftermarket options if there's a compelling reason to use it instead (like it might play nicer with mixing).