HPOP reservoir draining

[threeboogitys]

I have a 95 PSD that recently lost high pressure oil resulting in our replacing the HPOP along with the IPR. Before replacing these items,, the HPOP reservoir would always be full of oil when checked at the pipe plug. But now,, immediately after replacement of the HPOP pump,, the oil is draining out of the reservoir after sitting overnight. After replenishing manually in the morning to be able to start,, the truck will run and start all throughout the day. Any ideas of what might be causing this drain back issue??

[threeboogitys]

..................

[Sam Burton]

i haven't had this problem but if you put a later model hpop on your early psd, you will have drain back problems. they changed the resevoir and pump on the later trucks. not sure if this is your problem, i'm sure someone else on here will have other ideas too. there are posts on here about how to make the late pumps work.

[House22]

how many miles on it? my 97 with 270k does the same thing has a cracked front cover on the motor and hpop oil leaks from it.

[moore20017.3]

Hope you got this resolved by now. But for future refrence for others.

I had the same problem on a 2001. It was worse when I parked with front end above rear. I would have to remove plug and fill hpop res with oil (a real pain when oil is cold). I talked to several Ford dealers and no one gave me any help what-so-ever. I finally talked to an International Tech in North Carolina that offered some help. If the low pressure pump, behind harmonic balancer, is worn out it will lose prime and oil will return to case. I took the truck back to Ford and told them to replace the low pressure pump against their recommendations they did and no problems for three years now. The pump was only $100.00 or so if I remember from Intl.