Hello all and best wishes for 2017.

I am at my wits end trying to find and fix an oil leak at the HPOP.

Some months back the truck developed an oil leak and I decided it was
related to the HPOP as it was leaking quite a lot and was leaving oil
at the front of the valley.

I removed the pump and replaced all the O rings, seals and plugs,
including doing the "unservicable plug" fix.

I also replaced the ICP regulator and ICP sensor at the same time.

Refitted the pump with a new gasket and tightened to the recommended torque.

I believed I had the problem fixed but a short test run proved me
wrong, more oil in the valley.

On close inspection I noticed that the was signs of oil leaking from one
of the fittings where the replacement CNC aftermarket HP oil lines was
screwed into the pump. It seems I had damaged the O ring when fitting the line.

Relieved that this was a cheap and simple fix I removed the fitting, replaced
the O ring, and reattached the fitting using the recommended grade of Loctite.

Another test run and once again oil in the front of the valley.

I can not find where it is leaking and I can't afford to keep pouring
expensive engine oil along the road. Any advice as to how to track
down the leak will be very much appreciated as this one has me stumped.

 

Sounds to me that you have checked everything that could be the culprit
If it was me I would clean everything down good enough to eat off, start her up and get a camera down there. The ones with the flexible line

 

Brian,
Thanks for the response.
The camera idea is pretty much my thinking as well.

Getting one of my big mits under the pump to clean it is a
bloody tight squeeze but I will do the best I can and then
get the camera in there.

Do these pumps ever develop cracks in the housing?
I did not see any when I had it off but I could have missed
a very fine crack I suppose.

 

It often cracks in the reservoir (or the cover). Look real close with a good light at your front engine cover while someone is reving the engine if you can.

Good news is, if that is the case, if you clean the surface properly, you can use JB weld on the crack in the reservoir.