Good morning! Cranked my newly rebuilt D4 engine on the electric starter and pegged the oil pressure gauge! I also found (or blew) a hole in the oil cooler. To bypass the cooler, do the tubes need to be looped, or would plugs do? Concerned about closing a loop and hurting something else. Are they the same thread as a JIC or what are they? My new oil pressure gauge only tells me I have enough oil pressure through a wide range, what should the oil pressure be on a cold new rebuild? Thanks to all! Elton

Remove spring 5H2739 and plunger 4B479 from bottom of filter housing. Plugs are 2D2182 and gaskets are 8B3410 from Cat

Elton wrote:

Good morning! Cranked my newly rebuilt D4 engine on the electric starter and pegged the oil pressure gauge! I also found (or blew) a hole in the oil cooler. To bypass the cooler, do the tubes need to be looped, or would plugs do? Concerned about closing a loop and hurting something else. Are they the same thread as a JIC or what are they? My new oil pressure gauge only tells me I have enough oil pressure through a wide range, what should the oil pressure be on a cold new rebuild? Thanks to all! Elton

our d4 had a shagged oil cooler too so what the mechanics did was get a aftermarket transmission cooler for a Toyota land cruiser and mounted that in front of the rad as oil cooler cores are NLA from cat you can get a full rad core and gaskets though. they simply pulled the rad apart and resurfaced the flange faces with devcon and any corroded areas got the devcon treatment too then reassembled with new gaskets. the replacement cooler was plumbed to the factory ports on the engine. it works like a dream. we kept the oil cooler as we are in a hot climate. besides cat designed them with one so there was a reason.

the oil gauges on these old girls are only to indicate if oil pressure is too low and not the actual amount. I read in another post that as long as they have a minimum of 5 psi pressure at idle that is fine. the gauges are more like an oil pressure light on your car.

POR 15 is good stuff it's dearer than devcon epoxy adhesives and puttys and once cured devcon can be drilled, threaded or filed. i hope it works for you. remember it is only a anti corrosive paint not a filler. not sure how it would handle coolant and heat at the same time. their fuel tank sealer might be a good choice.

Thank you all for your help! Do I need to check the pressure with a real gauge to make sure I didn't blow out the cooler with too much pressure. That is why I was hoping to get a top end cold pressure range. Thanks again! Elton

Cat just went with a wider core radiator and eliminated the oil cooler on later tractors.

I don't run those coolers in my cat stuff. They don't give notice when they let go, sooner/later they go. If you want it to look original but not pressurize cooler, remove piston and spring from bottom of filter housing, remove and clean lines use wire pipe cleaner. Next put some wadding in the lines and put in a good amount of mixed jb weld to plug and let cure. Lastly put lines on, who's gonna know?