Leaking transmission fluid into the radiator reservoir?

Tiny
HMANN59
  • MEMBER
  • 2007 HONDA RIDGELINE
  • 3.5L
  • VR6
  • 4WD
  • AUTOMATIC
  • 118,500 MILES
I have transmission fluid leaking into the radiator reservoir. How can I fix this problem? Thanks
Saturday, December 17th, 2022 AT 11:02 AM

3 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,747 POSTS
First, if you are getting ATF in the cooling system, it sounds like the cooler in the radiator is leaking. I wouldn't drive it until we make sure there is no coolant getting to the transmission.

Do me a favor. Check to see if there is evidence of coolant mixing with the transmission fluid. If there is, the radiator will likely need to be replaced. Transmission fluid goes through the lower section of the radiator for cooling and then to a remote cooler at the front of the vehicle before returning to the transmission. If the radiator's internal cooler has failed, you will see ATF in the coolant. (I attached a pic below showing where the radiator cooling hoses attach).

Let me know what you find. Again, if there is evidence of coolant in the transmission fluid, don't drive it until the leak is resolved and the transmission fluid has been completely flushed.

Let me know if this helps or if you have questions.

Take care,

Joe

See pic below.
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Sunday, December 18th, 2022 AT 11:28 AM
Tiny
HMANN59
  • MEMBER
  • 1 POST
It doesn't appear to have any coolant mixed with transmission fluid. What now?
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Monday, December 19th, 2022 AT 9:22 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,747 POSTS
Hi,

The radiator will need to be replaced. The cooler is non-repairable.

Here is a link that you may find helpful. It explains in general how to replace a radiator. Use this as an aid.

https://www.2carpros.com/articles/how-to-replace-a-car-radiator

Additionally, I attached the directions below specific to your vehicle for replacing the radiator. The directions indicate the replacement of the radiator and cooling fans. You won't need to replace the fans.

Let me know if this helps or if you have other questions.

Take care,

Joe

See pics below.
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Monday, December 19th, 2022 AT 1:54 PM

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