Hpop Reservoir draining

For some reason my 99 7.3s hpop reservoir is draining over night causing my truck to take longer to start especially when it was cold out. Could it possibly be injector o-rings? I do get some white smoke when starting up especially when its cold out. Any thoughts?
Thanks!

It could be injector o rings, or any number of other things. The hpop resovoir sits above everything else in the hpo system, so those things can drain the hpop res

What else could drain the hpop reservoir? Any tests that I can do to narrow it down to what the problem is?

Have you actually pulled the hpop resovoir plug and checked the oil level before starting it, or are you just guessing?

I just pull the check plug up top and put a clean 6in long screw driver down it to check the level and it usually comes out clean with no oil. After its warm and I go to start it up throughout the day it stays full. Thats Im thinking its some type of o-ring thats worn and is leaking after the truck/oil is cooled down.

Mileage on motor? Lpop ever been replaced?

That's strange...should be the reverse. When oil is cold its thicker, therefore less prone to leaks. When its thing is normally where **** starts leaking.

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To be clear BEFORE you ever try to turn the engine over you check the Res and there is no oil in it? Should be about 1" below the access port hole. A piece of wire or dowel rod down the hole if your eyes are not that good or its otherwise hard to see. Given that is the case and no oil in the res proceed with troubleshooting.

Also assuming there are not symptoms such as the valley has standing oil in it etc. You are not having to add oil to system such as from a external leak. Stuff like that. Make sure there is no oil pooled in the front of the valley or under the HPOP. Use a flash light and small mirror if need be to check.


Possibilities:


Injector related: unhook the HPOP line from each head and tie it up so that open end stays above the top of the HPOP. Make sure the HPOP is full and leave it over night. If the HPOP still is drained you know its not anything to do with the injectors. If it is not drained you know its one of the injector banks. Hook one line back up to the head (say the Driver side to start) and see if it now drains. If it does drain the problem is on that bank. If not its the other bank but confirm it still by unhook that first one (driver side in this case) and hook up the other(passenger side). It should drain confirming that is the bank. It could also drain from both banks thus why you really need to check both no matter what as more than one injector o-ring might be leaking. If its a injector related issue its time to pull the valve cover/s for the side/s that shown leaking. Cranking while observing the bank of injectors may visually show you one blowing oil otherwise its time to hunt.


IPR valve: I may not have all the gerbils in my head running on the wheel at full speed but I am not sure it could be the IPR. Even if the IPR was not fully sealing closed when power is cut would not that oil be returning to the reservoir, not draining down the front cover to the pan. So even if it was set to fully open it would only keep the oil in the HPOP system loop. As its and the injectors below the height of the over flow tube in the HPOP Res the oil would sit in that section as long as there was not leak on the injector side of or somewhere else in that section of the system.

As I said I am still shaking some rust off the old furnace so someone correct me if I got this all fubar'd. Sure Dave or someone else will kick me in the head to get it right.


Worn/damaged HPOP Res gasket: If the gasket is damaged between the res cover it can allow oil to drain down the front cover. Not that likley if you have not had the res off recently so if not chalk it up to not likely.


HPOP Gasket: Ifs its worn between the internal ports on the HPOP the oil can drain back down slowly over night yet still be sealed from outside leak.


The external Oil check valve: Personally I have never seen one of these fail personally were it caused drain back as the sole cause. Look down on the drivers side of the valley right behind the HPOP (if stock fuel system) below the fuel return line on the driver's side of the fuel filter, you'll see a round plug with square recess. Underneath that plug is a check valve. It has spring check ball that opens when oil pressure from the LPOP that initially supplies oil to the HPOP res on cranking.


I would start with the ones that take the least amount of tear down and go from there.

Tarm, I don't think the ipr will bleed off oil like that without the motor turning over, if so, this would be the first I've ever heard of something like that happening. But who the hell knows. Good to see you back on here. Could a cracked/ pitted front cover cause such an issue? I'm also wondering if a worn out lpop is able to bleed down the oil volume, or is that what that check valve in the top of the valley prevents?

take a look at what I said about the IPR. I stated I do not think it can bleed down a reservior.

I can see a front cover leaking oil but I do not see how it would cause oil to drain out of the Res but I do not have them infront of me and have not messed with the stuff everyday like use to so its not as fresh in my mind.

THe only way I see a worn out LPOP would be after cranking but not after the oil is up in the res as the only way again would be thru the check ball right as you stated Now if it was empty after cranking then yes the LPOP. That was the reason for the question in the beginning to be sure we were talking about prior to cranking situation.

So in the end all I see is something wrong with the gaskets, the injectors, or possibly the HPOP itself and check valve. EVerything else would have symptoms during running and or would not fit the draining down over night prior to cranking.

I never heard about disconnecting the HPO lines to eliminate or confirm the injectors. Good trick.

By the way, I added a not to your trouble shooting that you missed.

Oh, and welcome back, you have been missed.

The LPOP and HPOP both have been replaced within the year of my hpop res draining. Ive brought it to a mec and he said it was most likely the hpop failing so I went ahead and bought a new one and had him replace it (gran later) and still didnt fix it. Then after that wasting of money I did more research and found what you guys were saying about the lpop being warn out so I replaced that myself and still didnt do anything. Trucks got lil over 450k on it but once its started it runs perfectly and doesnt smoke at idle or have any weird noises and still gets 18+mpgs. So Im stummped.... But Ill try what you said TARM and go from there. Thanks guys!

Also there is no visual oil leaking outside besides a very small leak on my turbo pedestal. Oil stays right at full between my 6-8k oil changes

Original injectors?
If so, bet you have bad injector O-rings at least.

Yep with 450K if original even if they were changed at 1/2 that mileage is likley an issue.

Since Ive owned the truck I haven't pulled the covers which have only been for the past 60-70k

Well then pull the HPOP lings from the oil rails, have them above the top of the HPOP. Be sure to fill the HPOP. Check it the next day and see what you find.

I've seen HPOP's leak out the front and drain the resovior before too


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TARM said:

Well then pull the HPOP lings from the oil rails, have them above the top of the HPOP. Be sure to fill the HPOP. Check it the next day and see what you find.

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Dammit. Good to see you back helping out again. Sure have missed you in the tech 7.3 section. Seems like when people get one of those high tech new fangled motors, they forget about us guys that like the old crap.

Welcome back.

Love the old crap!