My oil cooler is leaking pretty good, seems like a bear to repair and worse to replace. I've heard of bypassing it and it being okay due to modern oils and less working hours.

I need it to push up burn piles and the temp is around 105+ outside these next few months, could use some input. Would it be okay to bypass it?
9U11838

I also noticed that a few of my greaseable rollers have blown out seals, are the seals available? 

On D2/D4 oil cooler bypass was a standard thing to do, not sure about D6's
The seals may still be available from your local dealer, look up the part number in the catalogue and check online if they have it.
Usually blown seals means they have used the grease gun too vigorously, got to be real careful adding grease to rollers to avoid damaging the seals.

what we did for our d4 was get a aftermarket transmission cooler for a landcruiser and mounted that infront of the rad. the mechanic also pull the rad tanks off and coated them and the core with devcon epoxy and blanked off the oil cooler core.

Bypass it. Not really necessary in colder climates. My D6's had theirs bypassed and never caused a overheating problem even in 40 degrees C heat.

Some of you suggested that he bypass, the cooler; should he need to do anything to the filter housing? Are there any springs or check valves inside that need to be gutted, or can he simply "loop" the oil lines to return? Wondering myself, if I ever need to take a shortcut for a leaking oil cooler. Thanks, JM

Juiceman bloody great point!! I guess that research would be required to find out if,
1. It is full flow with permanent flow regardless of temp of oil and/or oil pressure and/or oil restriction in filter?
2. It maybe a bypass style that only gets flow from restriction to oil filter?
3. It may have flow only when at running temp due heating a spring to open journal to supply cooler?
Possibly ok to bypass cooler directly back to engine port, without attention to oil filter housing or may need modifying/removal of parts within housing.
Like TK88 suggested add another that easy to fit and have access to is a great option as well and helping cool the oil.

Food for thought
Jamie

All the information about by passing the oil cooler is buried in this forum some place. I believe it could have been a Cat service bulletin even but not sure. From memory (real dangerous) I think removing a check valve was all that was needed in the model being discussed at the time. But again, only a guess, but think it was 6u,7u D4.

If you're in a high temp climate I would put a full width core radiator in if you're not going to use the oil cooler.

I ended up bypassing/looping it and have had no new noises so far. Was able to run it 8-4 for a few days running around pushing piles no problem. Finally ripped the old one out and I have a hydraulic cooler lying around that's about the same id and probably half the size . I know it has spiral flutes in it to slow down the oil. Any objections to hooking it up?

The one next to the old cooler is too big to shove in the rad case

what we did for our d4 was get a trans cooler for a landcruiser and mount that infront of the rad. it works just fine.