What would you do?

[Firetrol]

Check the condition of the OE intercooler with the Patrol
being 6 years old chances are the IC is oily and leaking.
Buy a Tig welded one to replace it'
You'll find fitting the Beaudesert 2.75" exhaust a better option
for the CRD..
Dont bother about blocking the EGR or any other mods till you
have a way to monitor what changes occur first.

So remove the intercooler & check for oil residue, how would i know if it's leaking threedogs?