Mysterious Coolant Leak

[soursha]

So i had a coolant leak develop about 3 weeks ago on my 135i with the n54. Every time i shut the car off, the coolant would leak out but it wouldn't really get low while driving it. It was leaking near the water pump/thermostat. I checked and noticed a bit of a crack on the WP and replaced the water pump and thermostat with parts from FCP Euro. Now the exact same leak is still happening and i'm just annoyed. Has anybody ever dealt with this? What should i look for. The hoses seemed to be fine when i replaced the water pump and thermostat both, but should i look into those that connect to the parts? Need some help here lol. Thanks in advance

[soursha]

I just went out and checked and it's bone dry under the car. I went on a drive earlier and it was leaking at my destination and i had about a 40 minute drive home. No leaks or anything now. Also the reservoir is full so i'm just confused. Any help is appreciated

[WilsoN55]

I had a similar mystery with my 135i shortly after I purchased it. I replaced water pump, thermostat and a bunch of hoses, was still leaking.. turns out the reservoir itself was leaking under high pressure/temperature. Changed that in a few mins and I haven't had to touch my coolant levels since - may be worth a look.

[soursha]

Originally Posted by WilsoN55

I had a similar mystery with my 135i shortly after I purchased it. I replaced water pump, thermostat and a bunch of hoses, was still leaking.. turns out the reservoir itself was leaking under high pressure/temperature. Changed that in a few mins and I haven't had to touch my coolant levels since - may be worth a look.

I'll have to check it out - was the coolant going onto the WP?

[________]

So…

You have a "leak" you can't identify as it's dry, and the coolant is on level.

Not to sound pesky, but you have AC condensation water at your destination. No?

[soursha]

Originally Posted by Onesie

So…

You have a "leak" you can't identify as it's dry, and the coolant is on level.

Not to sound pesky, but you have AC condensation water at your destination. No?

Uhh nope. It's blue coolant. And seems to only leak when it's under pressure. I'm not that dumb lol

[WilsoN55]

Originally Posted by soursha

I'll have to check it out - was the coolant going into the WP?

I'm not 100% sure what you mean by was coolant going to WP? ... coolant was spraying on the hot side; frame rail, exhaust manifold, water pump area. Internally I wasn't losing much coolant until I stopped and kept the car idling, where coolant temps would rise and increase coolant levels in the overflow tank.

[soursha]

Originally Posted by WilsoN55

I'm not 100% sure what you mean by was coolant going to WP? ... coolant was spraying on the hot side; frame rail, exhaust manifold, water pump area. Internally I wasn't losing much coolant until I stopped and kept the car idling, where coolant temps would rise and increase coolant levels in the overflow tank.

I mean onto sorry. Maybe the thing to do is go on a spirited drive and come back to check the expansion tank. It happens every so often and not every time i drive the car but it's definitely annoying to see the low coolant light and empty tank

[________]

I just had an expansion tank leak. That sounds like what you have. When was the last time you replaced the tank?

[soursha]

Originally Posted by Onesie

I just had an expansion tank leak. That sounds like what you have. When was the last time you replaced the tank?

I just got the car a couple of months ago. I doubt it has ever been replaced

[________]

Originally Posted by soursha

I just got the car a couple of months ago. I doubt it has ever been replaced

Go for a drive and feel under the tank. If it's wet, it's it. Not expensive and the easiest part to change.

Get some BMW coolant and mix it 60/40 and do the self-bleeding procedure. Piece of cake!

[soursha]

Originally Posted by Onesie

Go for a drive and feel under the tank. If it's wet, it's it. Not expensive and the easiest part to change.

Get some BMW coolant and mix it 60/40 and do the self-bleeding procedure. Piece of cake!

I'll keep you guys updated. I'll have time in a couple of days to go for a drive so i'll check it out - thank you guys!

[NorthernDancer]

Really, really sounds like this item. BMW makes it out of plastic and it can crack. Cold, it contracts and doesn't leak. Hot, maybe it leaks but sometimes it may not. Very easy to see, top front of engine.
https://www.fcpeuro.com/products/bmw...e-rein-chc0609

[tracer bullet]

You could consider adding dye to it and getting a black light flashlight. Should find it right away.

Or of course semi-clean the engine and make sure things are dry. Then go around with a white rag at any and all leak possibilities and see which one makes the rag blue.

[iminhell1]

Might just be the Coolant Level Sensor is leaking. It's just a quarter twist to hold it in place and an O-ring on the back to seal.
I had one fall out and it only leaked a little. There's a one way valve behind it in the tank.

[soursha]

Originally Posted by iminhell1

Might just be the Coolant Level Sensor is leaking. It's just a quarter twist to hold it in place and an O-ring on the back to seal.
I had one fall out and it only leaked a little. There's a one way valve behind it in the tank.

So i've been driving the car and as i said i JUST replaced the pump and thermostat. To me it seems like it's coming from the brand new continental pump again from pictures. I'm confused and frustrated - if anyone notices anything from the pictures please let me know. The thermostat to wp hose looks like it has some cracks in it too but i don't know if it's possible for it to leak onto the plug? Doesn't make sense to me

[soursha]

Originally Posted by NorthernDancer

Really, really sounds like this item. BMW makes it out of plastic and it can crack. Cold, it contracts and doesn't leak. Hot, maybe it leaks but sometimes it may not. Very easy to see, top front of engine.
https://www.fcpeuro.com/products/bmw...e-rein-chc0609

I replaced this already and it seems dry to me.

[soursha]

Originally Posted by soursha

I replaced this already and it seems dry to me.

So i have pretty much determined my BRAND NEW water pump is leaking 🤦🏽*♂️ this is absolutely the dumbest part on this car after owning multiple N54s. Now hopefully FCP will replace it and ship a new one out asap

[________]

Originally Posted by soursha

So i have pretty much determined my BRAND NEW water pump is leaking 🤦🏽*♂️ this is absolutely the dumbest part on this car after owning multiple N54s. Now hopefully FCP will replace it and ship a new one out asap

What do you mean "hopefully"? You just need to buy a new one and install it, correct?
You then ship them back yours and get a refund.

[soursha]

Originally Posted by Onesie

What do you mean "hopefully"? You just need to buy a new one and install it, correct?
You then ship them back yours and get a refund.

I have a wholesale account with them and they don't warranty wholesale parts. I just installed it a couple of weeks ago but i bought it like a month and half ago

[________]

Originally Posted by soursha

I have a wholesale account with them and they don't warranty wholesale parts. I just installed it a couple of weeks ago but i bought it like a month and half ago

Ah didn't know that existed. What's the benefit? Lower costs for parts?

[soursha]

Originally Posted by Onesie

Ah didn't know that existed. What's the benefit? Lower costs for parts?

Yes it gets a decent discount on most parts but i'm sure they will honor the warranty since the part is so new haha.