Need help with a coolant leak

chewable · 01-28-2023, 10:19 PM

2011 bmw 328i e90 n51

Noob here. Appreciate the help i can get
I had been smelling oil when starting the car. Checked the ofhg and valve cover as best as i couldnt and didnt see an obvious leak. Had my oil pan gasket changed 2 years ago. Now, also seeing a slow coolant leak. I couldnt identify a leak from above and pulled the undercarriage cover and see the attached photos by the oil pan. Looks like the seals swelled. Thought the water pump might be leaking but its hard to find a source. When i start the car up there want an obvious leak i could identify unfortunately. Has anyone encountered this before? What is the likely culprit?

Looks like the rubber seals have swelled. I don't see anything clearly coming from the water pump

Appreciate any insight.

Images are undercarriage center.

View post on imgur.com

e91Owner · 01-29-2023, 09:20 AM

A leak from the connections on the pump would likely pool on the bottom of the pump body, which I don’t see here. The typical culprits in system leaks are at the fittings and at the expansion tank. For the fittings the two most common are the Mickey Mouse flange and the flange that connects the radiator to the heater core. Both you can see from the top of the engine.

Something good for this kind of thing is a bore scope camera if you don’t have one. They’re cheap on Amazon and it prevents you from taking apart the car to find sources of leaks.

01-28-2023, 10:19 PM	#1
chewable New Member 3 Rep 18 Posts Drives: 2011 BMW 328i e90 Join Date: Nov 2019 Location: Orange County, CA iTrader: (0)	Need help with a coolant leak 2011 bmw 328i e90 n51 Noob here. Appreciate the help i can get I had been smelling oil when starting the car. Checked the ofhg and valve cover as best as i couldnt and didnt see an obvious leak. Had my oil pan gasket changed 2 years ago. Now, also seeing a slow coolant leak. I couldnt identify a leak from above and pulled the undercarriage cover and see the attached photos by the oil pan. Looks like the seals swelled. Thought the water pump might be leaking but its hard to find a source. When i start the car up there want an obvious leak i could identify unfortunately. Has anyone encountered this before? What is the likely culprit? Looks like the rubber seals have swelled. I don't see anything clearly coming from the water pump Appreciate any insight. Images are undercarriage center. View post on imgur.com Last edited by chewable; 01-29-2023 at 02:15 AM..
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01-29-2023, 09:20 AM	#2
e91Owner e91Owner 441 Rep 1,149 Posts Drives: 2011 e91 Join Date: Mar 2018 Location: Out of the Office iTrader: (0)	A leak from the connections on the pump would likely pool on the bottom of the pump body, which I don’t see here. The typical culprits in system leaks are at the fittings and at the expansion tank. For the fittings the two most common are the Mickey Mouse flange and the flange that connects the radiator to the heater core. Both you can see from the top of the engine. Something good for this kind of thing is a bore scope camera if you don’t have one. They’re cheap on Amazon and it prevents you from taking apart the car to find sources of leaks.
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