[Traxk888]

Hello there, I have a 2011 BMW 335i XDrive N55 E90 that’s has a coolant leak on the lower driver side. The coolant only leaks when car is warmed up 240° oil temp. I inspected the hose and it doesn’t look damaged. Would it be the radiator?

[Serf27]

Replace the o ring on the hose first.

[jsunma]

Yeah, looks more like the o-ring in the hose than the radiator itself.

This is a situation, btw, where SMALLER pictures would help as they'd allow for easier viewing of the whole pic/area.

But yeah, since you've obviously already pulled off the hose, I'd change that o-ring, put everything back together and see if it still leaks. If it does, replace the hose. It doesn't look like it's the radiator itself.

[Traxk888]

Thank you for the reply’s! I shall try a new o ring

[SF07e70]

Def try the o ring first but I do see some coolant on the radiator find in the first picture.

I’d suggest a $40 coolant pressure tester while you’re working on it.

[jsunma]

You can borrow a coolant pressure tester kit from any of the big chain auto parts stores. Comes with all of the adapters you need.

[NorthernDancer]

Is it the hose with the Mickey Mouse flange at the top? The MMf sits top, center facing frontwards of the engine. In any case, best to buy one [<$45] and keep it in the glove box or just install it. OE is plastic, develops cracks slowly and leaks down the hose.