Oil coolers better or worse for FE, was thinking of installing on Jeep
 

Dont have an oil cooler now just thought for better FE, honestly i dont have a clue how hot the oil is now.

I do have a tranny cooler now to keep that running cool its just your basic auto with overdrive.

i do run amsoil low viscosity in everything front to back top to bottom.

Ive read that oil needs to run certain temp or you will loose fe, just curious on your thoughts

95 jeep cherokee 4.0 auto

Hi,

I can't think how cooler oil would affect FE? The cooler itself will add some aero drag, however.

I haven't ever seen anything about an optimum oil temp for economy. Other than losses from non-synth oil, which can be more viscous at a cold start.

And Neil has a valid point about increasing aero losses by adding a cooler. That airflow could otherwise be directed around the vehicle instead of throught the rad, engine compartment & underneath.

Not worth it. The engine was designed to run at the temperature it does. The oil is capable of handling those temperatures. Cooling the oil will essentially make it 'thicker' and thus increase losses from having to pump a thicker oil.