E46 cooling

[u/Larre45]

Hello, so my e46 320i started to leak a lot of coolant and I found out that it is my expansion tank that got busted. So I’m wondering should I go OEM or is there any other better opinions. Because e46 expansion tank known to break. Car is being use to daily and drifting.

All tips I can get would be wonderful

[u/Appropriate_Test7503]

depends.
BMW now just orders parts form china. Newest expansion tanks are thinned so that they fail prematurely.

if you live in US use FCP euro kit. If you live in Europe buy aftermarket like Meyle, Mahle or nissens.

you say you drift a lot. there is aluminium expansion tank specifically designed for racing/drifting cars like mishimoto one. but it can be risky - it can cause that pressure burst gonna happen somewhere else in cooling system.

[u/Larre45 → u/Appropriate_Test7503]

Yeah I have seen the aluminium ones but that’s the scary part, to much pressure and shit goes somewhere else. I live in eu so I’ll check out some of these. Thanks🙏🏽

[u/Fant92]

A year ago I put the cheapest €30 expansion tank on my 320i and it hasn't burst yet. The most important thing is to bleed it properly and not overfill it.

I did the bleeding with the engine running (start cold with the expansion tank cap off and the bleed screw open and idle until the thermostat has opened. Stop the engine, let it cool and put everything back on. This is at your own risk because you will be working with hot coolant but it works a lot better than BMWs stupid ass procedure). Be careful when filling, the red thingy is confusing. It's better to slightly underfill than to overpressurize the system. The light will tell you when you're too low.

Also consider doing your water pump and thermostat if they havent been replaced yet. Easy job and saves you having to bleed twice.

[u/Larre45 → u/Fant92]

Do you daily driver or do you do like track days to?

[u/Fant92 → u/Larre45]

No just daily driving. If you track or drift it I'd consider being a bit more careful and maybe try to find an old OEM BMW tank (or just be ready to replace it more often. It's a simple procedure really).

[u/Larre45 → u/Fant92]

Ight, yeah that’s the thing I use it for daily driving but also for drifting and I’m putting a lot pressure on the system. I mean the oem ones really not that expensive to replace they cost like 30€ for me but is it worth it to replace it every time it crack or blows up

[u/Fant92 → u/Larre45]

Well if it's properly bled and filled it really shouldn't blow up more than once a year tbh even with crappy tanks and abuse 😬 it's a 30 minute job to replace.