Transmission oil cooler leak?

Tiny
BHAMDOC1973
  • MEMBER
  • 2019 BMW 428I XDRIVE
  • 4 CYL
  • TURBO
  • 2WD
  • AUTOMATIC
  • 113,000 MILES
This is a 2019 430i, RWD, didn't find the option for it so I have chosen 428, anyways, whenever I filled the expansion tank water was seeping from below, saw where something was broken on top of the transmission oil cooler, but couldn't see exactly what it is. I removed it but I don't see where this top black part connects to. It may be a transmission oil cooler thermostat that broke off of its place and connects to nothing, but I want to make sure. The bottom 2 connectors go to the transmission line and to the transmission, a side connector goes to a coolant hose on the bottom, but the top one that has broken off I see new ones have a clip inside it with a thermostat, but I don't see where it connects anywhere. Shouldn't there be a return line for the coolant? I marked it with an arrow.
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Friday, April 25th, 2025 AT 7:21 AM

3 Replies

Tiny
KEN L
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Yes, that is correct, that is the return line for the coolant. It looks like is it broken so you will need a new one.
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Sunday, April 27th, 2025 AT 12:22 PM
Tiny
BHAMDOC1973
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But there are no return hoses is what I am saying. It looks in the pictures of new ones that it has a clip inside it and is just blocked, nothing attaches to it.
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Sunday, April 27th, 2025 AT 12:59 PM
Tiny
KEN L
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Okay, that could be, makes no sense to me but I am sure they had their reasons.
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Monday, April 28th, 2025 AT 9:56 AM

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