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Trans oil cooler fittings at radiator


Well-Known Member
July 3, 2012
Reaction score
City, State
Ottawa, Ontario, Canada
Year, Model & Trim Level
2007 Lincoln Town Car
My son's 2007 Explorer EB 4x4 V8 (155,000 kilometers - 96,000 miles) recently developed a trans oil leak at the oil cooler fittings at the bottom of the radiator. Tightening the fitting slightly into the rad did not help the weeping; and the tube is not well secured with the lock into the fitting since some in/out movement (unlike fuel injector fittings). Called local Ford dealership to see what parts are available for repairing the weeping. No parts except new trans oil cooler tubes from rad to trans or a new radiator. No O rings are shown for the tubes to rad fittings.

Suspecting an O ring seal failure we took the fittings apart. Just one O ring per fitting that seemed to be worn or lacked end pressure to seal the fitting. Matched this O ring with Ford dealer's O ring set (just slightly fatter than old one). Installed 2 O rings per fitting and installed the fittings. No leaks and trans operated perfectly.

Has anyone encountered this problem and what were the fixes? In case this problem returns.

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depends what wore down, if the lines are worn, could be lines, else the fittings only come on a radiator. replace radiator.

In our case the O rings wore and were replaced.


Good to know, thanks for the info.

What was the part number of the o-ring you ended up using?

Did you get the repair fixed? I had the same problem when I replaced my radiator and used the remaining lines. The fittings started leaking one week later. Nn matter how I cleaned the lines, they would always leak after some time. Even the new fittings from the manufacturer would leak.. (I bought an aftermarket radiator online and was able to get replacement fittings under warranty. They do not sell them outright, however.)
I built my own connectors after seeing someone else's fix for the issue. I wound up going to the hardware store and bought two fittings used for hot water tanks. A screwed-in end with a hose fitting on the other. I took the fittings from the truck and sawed off the quick-connect portion. I took the remaining and brought to a machine shop where he drilled, tapped and died a hole that I could screw those hot water tank fittings into. I cut the transmission line ends off and flared them. Used high pressure rubber line and clamps to hold everything. Never had a problem

We got the O rings from the Ford dealer's box of miscellaneous parts, just matched them for diameter and thickness. The dealer said the O rings were not available from Ford.

The other issue we found over time was the alignment of the hose leading to the quick disconnect fitting. The fix for us was to align the hose to go straight into the fitting instead of at an angle.

The combination of new O rings and re-alignment of the hose has lasted for a very long time without any leaking. I was tempted to fit plumbing fittings into the radiator and connect with a hose to the two lines. But it has not proved necessary.

Because of the earlier trans leak we checked the trans oil level and added a pint to bring the level into the middle of the crosshatched area when trans was cold, and engine running in park on level surface (all four corners on axle stands). It is a bit awkward because the exhaust is very close but easily doable. If the engine is not running the oil overflows the dipstick hole.

Good luck.

These fittings are available....

I saw some replacement fittings are available at
These change the clip type fitting into a compression type fitting.