Do you have a leak at the oil cooler?

 

Yet to pull out, but I'm hoping it's the gasket

 

Do you have a V6? I change the seals on the oil cooler. Had to take the whole intake manifold, thermostat, alternator just to gain access. The replacement seal on the bottom does not fit like the original but it will seal, or at least it sealed in mine. What a job to get to the cooler!
If you require any pics or assitance, let me know.
I used a flexible head box end ratchet to tighten the the cooler back on the engine mount. Think it was 27mm