Can an HPOP leak cause extremely low LPO pressure?

texascadillac42

texascadillac42

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04 F350, 114k miles. At cold idle, the truck has 25psi oil pressure which quickly drops to 15, then basically 0 as the truck warms up. Truck requires 15sec of cranking to get it started. Can a leak be big enough in the HPO system to cause extremely low oil pressure on the LPO side, but still allow the truck to run?
 
No not really, it will run out of HPoil in the resevoir, and it won't suck oil from the LP side. LP dumps into a resevoir for HP oil. I could be wrong, but I don't think its possible. Have you checked to see if it has an oil cooler leaking?


Here is a schematic.
ps60_041_Fuel_Management_System.jpg
 
Oil and coolant both look ok. Oil cooler was replaced about 1000 miles ago when an EGR delete was done. Thats not to say the oil cooler isnt defective, but from what I can tell so far it is ok.
 
I'm thinking along the same line as Tim
I don't see how anything on the HP side could cause low oil pressure.

I wonder if the bypass at the oil pump hung wide open or something and it's all bypassing instead of moving upstream ?

Where are you taking your pressure readings from ?
 
Mechanical oil gauge is screwed into the top of the oil cooler, where the factory EOP switch is normally screwed in. I can pull the line off of the gauge with the engine running at 1200 rpm and it will just drip oil onto my hand. No real pressure at all.

I have pulled the oil pressure relief valve out of the front cover and looked it over. The spring seems to be in good shape (not broken or deformed) The valve seemed to slide fairly smoothly in the bore.

I would like to leave the truck running to see if it ever shuts itself off due to a lack of oil in the HPOP, but I hate to run the motor with basically 0 lube oil pressure. I will have a scanner here this afternoon to read what the ICP is seeing.

Should I be lookin at the LPOP next?
 
Look at the LPOP.

But if the leak is large enough in the high pressure system, it will drain the low pressure supply. Not like its sucking it dry, but more of its easier to flow out the leak than to go to the bearings and all that other good stuff.
 
I would look harder at the oil pump bypass. I have heard of a oil filter housing drain being broke open and it allowed the oil to drain back to the pan faster than the pump could fill the housing at idle. But that seems like a long shot to me. HPOP has 0 effect on LPOP pressure, as the res. is a non-pressurized part of the oil system. Think hose in a bucket. No matter how quickly or how much volume you remove from the bucket, you will have no influence at all on the delivery pressure of the hose.
 
Thanks guys, I will recheck the oil pump bypass, as well as the drain valves and bypasses in the filter housing. If everything still looks ok there, I will take the oil pump out.
 
SINNER said:
I would look harder at the oil pump bypass. I have heard of a oil filter housing drain being broke open and it allowed the oil to drain back to the pan faster than the pump could fill the housing at idle. But that seems like a long shot to me. HPOP has 0 effect on LPOP pressure, as the res. is a non-pressurized part of the oil system. Think hose in a bucket. No matter how quickly or how much volume you remove from the bucket, you will have no influence at all on the delivery pressure of the hose.
Click to expand...

Like I said. Ford disagrees. And have said it could happen since October of 2006

19417 2003-2007 F-SUPER DUTY/2003-2005 EXCURSION 6.0L - WATCH FOR OIL FLOW FROM THE BASE ENGINE OIL PUMP
SOME 2003-2007 F-SUPER DUTY AND 2003-2005 EXCURSION VEHICLES EQUIPPED WITH A 6.0L DIESEL MAY EXHIBIT LOW BASE ENGINE OIL PRESSURE CAUSED BY A LEAK IN THE HIGH PRESSURE OIL SYSTEM. IF A HIGH PRESSURE SYSTEM LEAK IS SEVERE, THE HIGH PRESSURE PUMP MAY USE A LARGER VOLUME OF OIL THAN THE BASE ENGINE (GEROTOR) PUMP CAN PRODUCE WHILE CRANKING. IF BASE ENGINE OIL PRESSURE IS LOW, REMOVE OIL FILTER, HOLD DOWN THE OIL DRAIN VALVE (LEFT SIDE OF HOUSING) WITH A SCREWDRIVER AND CRANK THE ENGINE WHILE WATCHING FOR OIL FLOW FROM THE BASE ENGINE OIL PUMP. IF FLOW IS PRESENT, USE THE UPDATED DIAGNOSTICS FOR THE HIGH PRESSURE OIL SYSTEM (ELECTRONIC VERSION OF PC/ED, SECTION 4, STEP 10E). IF THERE IS NO FLOW AT THE OIL FILTER HOUSING DIAGNOSE THE BASE ENGINE OIL SYSTEM FIRST (WORKSHOP MANUAL SECTION 303-01C).
EFFECTIVE DATE: 10/06/2006
 
HPOP cover came off today. Should oil be pumping out of a port on the drivers side of the HPOP, right next to the 2 mounting bolts on that side? Or is something wrong with this HPOP? Thanks for the help and suggestions so far.
 
Yeah. Thats the port to the IPR and the cover has a spot in it for an o-ring. What you need to do is put the block off tools in each each head and start isolating your high pressure leak. If both heads are blocked off and still no high pressure oil, then you have narrowed it down to the pump and branch tube.
 
Yea that makes sense. I looked at it quickly before I ran home to eat dinner, so I didnt have much time to study where the port was in relation to the cover. Block off tools will be ordered tomorrow. Thanks for the help.
 
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After re examining the HPOP cover, that port on the side of the HPOP is not where the IPR valve goes. The IPR was still screwed into the cover when I pulled it off,and the end of the IPR is buried inside the cover. Here is a pic, with the screwdriver pointing out where the oil is pumping out of.

DSC01634.jpg
 
Thats the pop off. You should not have a leak there. When you said drivers hole, I thought you meant the hole in the cover.
 
Oh, yea I explained it poorly. Pictures say 1000 words. So is there supposed to be a check valve or something in there? Its obviously gone, I assume I need a new HPOP at this point, or is this missing piece replaceable? Can the missing pieces make their way back to the pan, or are they floating around the HPOP area?
 
New pump. If it did make it to the pan it may or may not be stuck to the plug magnet. I don't know if the ball is stainless steel.
 
Sounds good, I will call International and get a new pump coming tomorrow, maybe tonight if the parts guys are still there....
 
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