Just to chip in here,,,,
I've read many posts regarding the necessity for Oil Coolers when a Sump Guard is fitted.
Sorry, but based on solid experience, I don't feel this is necessary unless for some competition work.
Our locally produced Mokes were all factory fitted with a (heavy) steel sump guard and no oil cooler. These guards don't have any cooling holes and competely encase the sump, not only from the front, but also the sided. The only opening is at the back. They are bolted up with 8 x 3/8" UNF Bolts and the Nuts are (factory) welded in to the Subframes.
We run these cars very hard when off roading and it's not just a 2 minute 'squirt' to get through a mud hole, but can be all day, day after day when going through soft sand. This often necessitates being in 2nd or 3 gear hour after hour and this can go on for a week or longer,,,, I'll also point out that when traversing such soft ground, speeds are slow, sometimes painfully slow (on one trip, 8 and 12 km over 10 hours was the norm), so even if an Oil Cooler were fitted, there'd be no air flow through it in any case. This is not just my own experience, but many members of our Moke Club and none of us while having red hot engines under these conditions, have ever cooked our oil. We only use a normal 25W50, though, I will say, in these sort of conditions, it does get changed at a sorter interval. Some may scoff at my next comment, but in many ways, the operating conditions we put these cars through well exceeds anything that's ever seen any any type of competition work, though I say this, I don't mean for this comment to in any way 'put down' competition conditions, as these I know all too well are also tough on any car.
I've just done 15 hours / 1400 km in my own Moke, sitting at cira 4100 RPM for just about that entire 15 hours - with the sump guard on.
