Trans cooler leak into radiator (maybe)

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Topic author
JWestfall
Posts: 83
Joined: Fri Feb 05, 2021 12:39 pm
Location: North Eastern California

Trans cooler leak into radiator (maybe)

Post by JWestfall »

No matter how much I flush my cooling system it always comes out brown with a hint of red (almost immediately after flush). I suspected trans cooler, but when I pull the dip-stick the fluid is always clean as a whistle. Can the trans cooler leak into the radiator but no water get into the trans fluid? Any other ideas? (1971 Wagoneer w/360) Thanks

letank
Posts: 4010
Joined: Wed Oct 03, 2012 9:16 pm
Location: SF bay area

Re: Trans cooler leak into radiator (maybe)

Post by letank »

Do you have an external trans cooler as well as the radiator trans built in cooler?

in your case disconnect the ATF line at the radiator (yes ATF will dribble, you can park with the nose up...) then connect both line together.... either with a union or using a single hose if you have slip on barb connectors which is probably the case as someone must have replaced the radiator at some point in the last 40 years.

These connections need to be tight, as soon as you are starting the engine the trans fluid will circulate. No need to start the engine first, check if coolant is leaking in a first test... then warm up the engine and monitor for leaks.

BUT if you have the OEM set up which are crimp on hoses and on the other side i a flare nut fitting -forgot the name- on the solid metal transmission line ....this is trickier, let's what you have?

my set up with external cooler

Image
Michel
74 wag (349 Kmiles... parked, next step is a rust free body)
85 Gwag (229 Kmiles... the running test lab)

Topic author
JWestfall
Posts: 83
Joined: Fri Feb 05, 2021 12:39 pm
Location: North Eastern California

Re: Trans cooler leak into radiator (maybe)

Post by JWestfall »

Thanks for the help. My Wagoneer sat for 30 years before I bought it, so after spending a lot of time flushing and cleaning this weekend I have decided the radiator has flow/cooling issues anyway due to a lot of build up inside and will need to be replaced regardless. I don't think it was leaking from the trans cooler, just 30 years of gunk.

letank
Posts: 4010
Joined: Wed Oct 03, 2012 9:16 pm
Location: SF bay area

Re: Trans cooler leak into radiator (maybe)

Post by letank »

ideally you should loosen the back drain plug in the lower part of the engine block ... but it is so rusted, that I never dared to do it.... on the diesel boards, people report that they are flushing a lot of sand due to poor cleaning of the casting materials.

Remember to use distilled water with the coolant, not permutted or Dionized water to prevent electrolytic effects and etching of some iron bits

a good talk on the mother ship

http://www.ifsja.org/forums/vb/showthread.php?t=190185
Michel
74 wag (349 Kmiles... parked, next step is a rust free body)
85 Gwag (229 Kmiles... the running test lab)
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