[BigJack75]

Is there a diy on replacing coolant for a 435i N55?

This is preventive not because something is wrong. Car is a 2015 and figure it's time to flush the system. I've seen the coolant flush kits but they are kind of pricey. Isn't there an easy way to drain and replace coolant?

[upsidedownfunnel]

Here's the BMW service manual:

Drain:
https://www.newtis.info/tisv2/a/en/f...check/IJQYEotN
Fill:
https://www.newtis.info/tisv2/a/en/f...check/CNCeB76L

Here's a DIY by a forum member for a 335i. 435 and 335i are essentially identical in the engine bay:

https://f30.bimmerpost.com/forums/sh....php?t=1278783

DIY seems OK. I'm not sure why he removed his expansion tank (what he mistakenly calls the overflow tank). That's not necessary at all unless your expansion tank is dirty with a lot of sediment.

You should use a coolant vacuum style fill tool to prevent air pockets as it shows in the BMW service manual. You might be able to borrow one from an auto parts store. Or you can find a decent one for about $75 from ECS Tuning or Amazon. Only use blue BMW coolant. It's cheap and you only have to do this once every 50k miles or ~8 years at the most.

[BigJack75]

Man thank you for the great response!!!! All the info I needed. I'm at 46k miles so I'm planning on doing this around 50k. I'm definitely going to use the bmw coolant but is the vacuum tool really needed?

Just read the diy you posted. It doesn't seem that he used a vacuum. So it seems pretty straight forward.

[upsidedownfunnel]

Vacuum is definitely necessary. You just have to be careful bleeding the coolant.

[Mr Podman]

I used to change my engine coolant every three years in my E46.
That's what BMW recommended.

The coolant hasn't changed and the engine block material hasn't changed but now BMW says it's "lifetime".

It's a mystery why. Of note though is Honda did the same thing.

In my case, I'm planning on owning my F32 for about 8-9 years and about 75,000 miles.
So for me, I'm never going to change the coolant.



podman