|
|
|
|
|
|
BMW Garage | BMW Meets | Register | Today's Posts | Search |
|
BMW 3-Series (E90 E92) Forum
>
Exhaust splattering water and black soot on cold start up
|
|
Yesterday, 07:02 AM | #1 |
@fast330i
0
Rep 7
Posts |
Exhaust splattering water and black soot on cold start up
Hello,
I’ve owned a X5M F85 2017 for a week now it’s my first M car! Pretty exciting to drive I’m loving it. Today I noticed on cold start I have some water and black soot, and it threw it on my car behind. Is this something okay? Anything I should check? I’ve attached the images below Thank you! |
Yesterday, 08:11 AM | #3 | |
Major
1502
Rep 1,444
Posts |
Quote:
Can be a sign of a coolant leak. If you smell anti-freeze from the exhaust and if you check -- and you should periodically -- the coolant level and it is dropping that's more bad sign. An analysis of the oil which among other things checks for the presence of anti-freeze compounds in the oil can confirm anti-freeze in the oil. The water content of the oil will be high too. In some cases a drain of the hot engine oil into a *clean* drain pan then let it sit a bit can have water (coolant) visible. It will be at the bottom of the drain pan under the oil. That's the worst possible explanation. But not the most common one. Thankfully. Much more often what you experienced arises from short trips. The engine combustion produces water vapor and this is carried out the exhaust. With everything cold the water vapor condenses back into water. If you run the engine long enough, drive enough, the exhaust heats up and the water leaves the exhaust. The next engine start will have no stockpile of water in the exhaust to blow out of the exhaust. But if you don't run the engine long enough the water can collect and to the point water droplets are blown out of the exhaust upon subsequent engine starts. The soot is like water vapor a byproduct of combustion. The water collects the soot and the water droplets carry the soot when they are blown out of the exhaust. In some cases an owner will report a puddle of water stained with some soot under the car. The water seeps through small gaps of the exhaust system joints. The cure is to avoid short trips drive the vehicle long enough to get the engine fully up to temperature -- I go by the oil temperature gauge -- and along with the engine up to temperature the exhaust gets up to temperature too and there is no water in the exhaust to make the spots next cold engine start. |
|
Appreciate
1
fast330i0.00 |
Yesterday, 08:11 AM | #4 |
Lieutenant
360
Rep 430
Posts |
All exhaust systems have water that condenses in them when you shut down a warm/ hot engine. When you start up again it blows the water out the tailpipe.
The black particles might mean you need to run that X5M a little harder and blow the carbon out. |
Appreciate
1
fast330i0.00 |
Today, 04:36 AM | #5 | ||
@fast330i
0
Rep 7
Posts |
Quote:
Quote:
|
||
Appreciate
0
|
Today, 07:33 AM | #7 | |
@fast330i
0
Rep 7
Posts |
Quote:
|
|
Appreciate
0
|
Bookmarks |
|
|