Complete cooling system overhaul

[ciscorob]

Marked the coolant tank and noticed it was going down and then after doing work on the oil pan I left all the coverings off to ensure no leaks only to find some coolant which had made it to the driveway. Its a 2016 BMW s35i with 101,700 miles on it.

I went ahead and got the following parts:

BMW-17127536235 - Expansion tank hose
BMW-17127586774 - Radiator Coolant hose
BMW-11537649409 - Coolant hose to the block from the t-stat (I believe)
BMW-17127576368 - Another one of the coolant hoses
BMW-17127576370 - Yet another hose
BMW-17127623272 - Recovery tank hose
PIE-702881660 - Water pump with new bolts
BMW-11537598865 - New T-stat
BMW-17138621092 - New Expansion tank
ELR-632090 - Oil filter housing gasket (just because, why not)

However, I noticed there are a few other hoses that I think I missed, namely these three:

11537649394
11537649304
11537645833

My question to anyone with some experience with overhauling the coolant system is, should I replace those hoses too? I can't pinpoint the leak, which appears to be coming from the passenger side but there just aren't any visible signs of the location. Any help is appreciated.

[Chilled]

Have you tried to use a coolant dye to see where the actual leak is coming from. These dyes are UV reactive, so they show up only under a UV light.

[ciscorob]

Originally Posted by Chilled

Have you tried to use a coolant dye to see where the actual leak is coming from. These dyes are UV reactive, so they show up only under a UV light.

I don't know why I keep forgetting this exists, lol. Well, all is done now, at almost 102K I figure its worth just replacing the components, I have it halfway taken apart now and enough of the o-rings are showing degradation that I wouldn't feel comfortable anyways putting them back on, I'm already $1,100 deep in parts, what is another $200-ish to know its all brand new. I did notice the coolant recovery tank was black and not opaque, I assume the old style was problematic?

[ciscorob]

I guess the one question I have is the coolant charge hose, as most of it it aluminum, how often has anyone seen the O-Ring fail on it?