Coolant Leak

IntellectG

New member
Hi Guys

My 2014 F02 740Li is giving me issues with the coolant. It doesn't hold coolant at all. I have been filling it but it does hold although it doesn't show it's leaking anywhere. What could be the issue?
 

TurboLlew

Honorary ///Member
how does your oil look?
Are you leaving large plumes of white smoke behind you when driving?
 

Coisman

Administrator
Staff member
My E46 325i 2003 had a water pump shaft seal failure causing coolant to leak, and I wasn't able to see it. Might look into that
 

IntellectG

New member
how does your oil look?
Are you leaving large plumes of white smoke behind you when driving?
Oil is fine, did an oil change last september. Nope it doesn't smoke at all. Its just that after filling up the coolant tank it goes for 2-5km and it wants to be topped up
 

husaindindar

///Member
Oil is fine, did an oil change last september. Nope it doesn't smoke at all. Its just that after filling up the coolant tank it goes for 2-5km and it wants to be topped up
Thats a substantial amount to not be noticed in the engine bay. Usually small leaks tend to evaporate before it can be found. Have you looked carefully in the engine bay? You can tug on the engine cover to remove it for a better look. It could be that the coolant is collecting in your undercarriage and not showing on the floor.
 

r0ckf1re

Well-known member
Hi Guys

My 2014 F02 740Li is giving me issues with the coolant. It doesn't hold coolant at all. I have been filling it but it does hold although it doesn't show it's leaking anywhere. What could be the issue?

I’ve got the same issue on my F25 X3 washer fluid, can’t see any leaks. Driving me mad, BMW says no issues.


Sent from my iPhone using Tapatalk
 

PsyCLown

Well-known member
Oil is fine, did an oil change last september. Nope it doesn't smoke at all. Its just that after filling up the coolant tank it goes for 2-5km and it wants to be topped up
It was leaking this much coolant already in September before you did the oil change?
 

Mytfine

Well-known member
Use a uv light, coolant usually has a dye in it and will light up like a disco so easy to spot leaks.
 

TurboLlew

Honorary ///Member
Oil is fine, did an oil change last september. Nope it doesn't smoke at all. Its just that after filling up the coolant tank it goes for 2-5km and it wants to be topped up

How much coolant is it using in those 2-5km? I ask because I recently had an education on why E46 owners go full nuclear on replacing the cooling systems when things like this happen.

I am not saying this is your case, but that's why I am asking just how much it is taking. Multiple factors caused by multiple things:

-Seam leak in expansion tank that only showed under pressure
-Aftermarket radiator cap
-Air in system caused because of items above leading to it 'burping' sporadically and dropping the level. We went crazy looking for leak after leak after the obvious candidates were found and ruled out.

After all this and having work done at BMW, they had confirmed that there were no leaks after pressure testing the car... but the level still dropped a week or so later which is when we ended up changing the very last missing link: The radiator cap :ROFLMAO:. Nobody suspected it because it was a 'new' part (Goldwagen)

Anyway the solution was to replace the items with OE and vacuum fill the system to eliminate all the air.

I agree with comments above: Pressure test the system, if no leaks, vacuum fill it and then replace your radiator cap...
 

tamgoem

Well-known member
The instruction was actually have you checked your oil for milkshake/emulsion.

If your oil is still as it should be then either you have a airlock, or you have a leak. If you have a leak and you added coolant and not just water you should be able to smell it with ease. If you can smell it you have a leak.
 

Solo Man

Well-known member
r0ckf1re, i had a F25 X3 that leaked under the water bottle for ages. Would once in about three months top up the water. Then when my son took over the car we found that the water bottle leaked from underneath where the pipes to the water bottle is connected. It had formed a whitish grey "aanpaksel" at the leak. Check under your water bottle.
 

Coisman

Administrator
Staff member
I pressure tested my system up to 2.5 bar, and we couldn't see the leak as it was behind the serpentine belt and pulleys.
 

Gordvisr

Well-known member
i do not want to be that guy but, it might go to your transmission You will not see where the coolant is going, i was lucky to notice a little bit of oil in the expansion tank. My coolant was also disappearing for a while before noticing the oil. ( Not saying it is/is not your problem ). Look for traces of oil in your expansion tank, smell and take it from there. If that is the case, the transmission cooler is leaking.
 
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