[gregrob]

I have had a bleed down issue for a couple weeks now. When the truck sits overnight the reservoir will bleed down and it takes forever to start.

I have confirmed it is the res bleeding down by sticking the dipstick in it before I started it up after sitting all night.

I went on a trip and gave the truck a pretty good work out. Got home and fixed the UVC harness issue I had and when I fired it up that day, it started immediately.
So the bleed down issue "went away" for a couple days.

Now it's back and worse than ever. I can let the truck sit just an hour or 2 and it bleeds all the way down.

I can crank til oil pressure comes up on the dash, and the truck starts immediately.

I have plans to check the HPO reservoir gasket to see if that is allowing it to bleed down, but I suspect not since I couldn't get ANY oil on the dipstick, even below what I think is the level of the gasket.

What else could cause this? The things of which I'm aware are
Check valves (how many and where?)
Worn front cover (I hope not)
LPOP (I have no trouble swapping in the Melling )

Let's hear your thoughts.


Thanks

 

[hotwheels]

I had a similar issue in the past. I don't seem to be having it anymore with this engine but I did put a new front cover on it. I've heard of a few others having issues with it as well. I can't say for certin what it is but I would definatly be interested to hear if anyone else has found a culprit.

 

[trick76cj5]

Here is what I've come across in digging for soulutions to my problem (see my post).

The HPOP resevoir has 3 ports for oil to get in or out:

1) There is a stand pipe in the resevoir that feeds the pump. This pipe runs the entire height of the resevoir to within .125-.25" of the top of the resevoir. This is the port that is fed via the check valve.

2) There is a port that dumps the extra volume of oil in the resevoir back to the front cover. This is a stand pipe as well and runs right next to the feed pipe. This port has a tiny hole in the end to meter the amount of oil it dumps back to the front cover to maintain pressure in the resevoir.

Both of these enter at the top of the resevoir and would be impossible for these ports to drain the resevoir.

3) The feed port for the pump is located at the bottom of the resevoir (well .25-.375" off the bottom of the res.). This port leads directly to the hpop. Were you to have an hpop leak or a bad seal in the hpop that would allow oil to pass through the pump and out the input shaft, you could have a drain back issue.

There is also a bleeder valve on the hpop that feeds back to a stand pipe just like 1&2, i think it is to help purge air from the system, or purge the crank case in teh pump (or something else, that's just a guess at it's application). . .but i don't think this can be attributing anything to your issues unless the hpop to front cover gasket has gone bad and is allowing cross flow between the cavities at that connection.

The other area that can cause a drain back from the hpop res would be a bad seal between the hpop res and the front cover between or the front cover and the front of the block. Either of these would allow for drain back issues.

Now, a LPOP could cause a seemable "drain back" issue, but this would be attributed to the oil pump itself taking a while to prime and feed the hpop res (but should only be problematic if you don't have a full hpop res to begin with. . .there should be enough oil in the res to atleast start the truck for a few seconds)

It has yet to be proven, I am still working w/swamps, but they think i blew the front seal of my gen III which is allowing the drain back issues and low oil pressure issues i'm seeing. I'm not sure if the Term or Stock hpop set ups can allow for such a scenario, but it's something to think about. . .but i'm not really sure how to test. . .i guess you could pull the cover off the front and see if you have oil leaking from the front of the pump.

Anyway, good luck, and let me know what you come across. . .maybe you can help w/my situation. . .i've been a bit tenative to replace the LPOP cause it's a pain to get to and a little $$$ if it's not the problem. . .my rebuild came with the updated Melling.

 

[TerminatorEngineering]

Gregrob, how low is it, when you checked it? Is it at the reservoir/timing cover gasket, or lower?

 

[gregrob]

Joey, I haven't removed the reservoir to verify, but I stuck the dipstick in as faaaar as I could wriggle it around in the res and did not get any oil whatsoever.

 

[gregrob]

Here is what I've come across in digging for soulutions to my problem (see my post).

Brad, thanks so much. That is a VERY useful post. I will let you guys know what I come up with.

 

[TerminatorEngineering]

Gregrob, did you check on the driver side or the passenger side of the reservoir? Driver side, I hope. If so, and it was empty, change your HPOP gasket.

 

[gregrob]

Driver's side.... that's where the port is.

 

[TerminatorEngineering]

Sounds like an HPOP gasket(sorry). Did the problem start after you re-installed the pumps with the R-IPR?

 

[gregrob]

Sounds like an HPOP gasket(sorry). Did the problem start after you re-installed the pumps with the R-IPR?

Nope, didn't have anything to do with that, only started maybe 2 weeks ago. :shrug:

Pumps are tight, brand new gasket when reinstalled, wasn't bent.

 

[trick76cj5]

Did you figure anything out yet?

 

[gregrob]

Brad, ordered a gasket and should be here tomorrow. Gonna pull the res and inspect/replace that, and try to pull the check valve and inspect/replace that as well. Got tomorrow off so I should get to it.

 

[gregrob]

Ok does anyone know where I can get the anti drain back valve?

IH could probably get it if I could explain it to them.

I've been told I need one with a "seat".

 

[trick76cj5]

from what i've been told, the seat rarely wears out. You should be able to measure the diameter of the ball bearing that is used for the valve and could probably order one from McMaster Carr if the ball bearing is scored. For what it's worth, the anti drain back valve is actually a bypass valve which allows unfiltered oil to feed the hpop resevoir and left side lifter galley. Once the pressure difference across the valve is equalized it closes and once again allows filtered oil to these two locations. . .I don't know for sure that it could drain your HPOP resevoir. . .I'll take a look at my housings again when i get home and get back w/you just to be sure i'm remembering 100% accurately. :shrug:

 

[gregrob]

I've heard of it getting stuck or worn and causing it to drain back, when it's not supposed to.

I got a new gasket, when I get some time I'll pull the res and see what I see, hopefully it's just the res gasket.
Next easiest is the bypass valve.
Then pull the pumps and replace pump gasket

 

[TerminatorEngineering]

Then pull the pumps and replace pump gasket

Piece of cake!

 

[hotwheels]

Any word on this yet? I thought I had my drain down issues solved but I think it's still doing it. If I drive the truck later in the evening and then again first thing in the morning (maybe 12 hours apart) then it seems to start OK but will usually fire for a second then die then start right back up and run fine. If I let it sit much longer than that it seems to take a bit longer to build oil pressure and runs rough until I get on it once or twice then runs great. It's got all new gaskets of of a little over a month ago as it was a fresh new engine including a new front cover. I'm kind of thinking it's something with the pump is leaking internally or something like that.

What have y'all been finding or have you?

 

[trick76cj5]

I swapped my gen 3 out for a new one, they're rebuildable, but Dave sent me a new on to save me some down time. They have had some issues w/the front seal leaking on the gen 3, my oil drainback seems to have been fixed by that. The casting for the resevoir almost looks like styrofoam on my truck, could you maybe have developed a hairline crack in the drain line in the casting?

 

[gregrob]

Well, stay tuned but I think it's fixed.

New HPOP Reservoir gasket. The old one wasn't blown out or torn, but it was FLAT more than normal and didn't fit the groove to well, wanted to buckle up.
The new one is round and laid down in the groove nice and snug.

The truck sat for 1 1/2hrs two different times tonight and fired right back up, where as it would drain in 20 minutes before.

Tomorrow morning should tell the story, after sitting all night.

Geoff, did you use a new LPOP, how did the front cover look?

 

[gregrob]

No such luck

The gasket seems to have helped it in the short-term, like sitting for 2hrs it will still start, where it would literally bleed down in 20mins before.

But sitting all night, reservoir is still bleeding down bone dry.

Maybe I have multiple issues :shrug: