Being new to the 7.3 have some questions on the subject of changing the oil in the HPOP.I have never read anything in the Owners manual covering this.Never knew there was a seperate oil resevoir on this unit either.Is there a dipstick to check it and how do you change it and at what intervals? Thanks in advance.

 

Your engine oil flows from the oil pump through the HPOP reservoir and ends up back in the pan. No reason to check the oil level unless you're troubleshooting something. Oil flows through there whenever the engine is running.

 

Chris- thanks for the reply.So in other words, this HPOP should be full of oil at all times ?? Why is there a hex plug on it? Do you check the oil level regularly or if the crankcase is full, so is the HPOP?

 

It's usually within an inch from the top if you remove the plug.. But no need to check or change it when you do oil changes, it mixes within seconds after start-up.. Only time to check the level is if it's leaking and your having issues.

 

Yes, the HPOP reservoir should be full at all times. There is a plug there so you can check the level while trouble shooting LPOP issues, drain back issues, or in case it drains down during extended cranking and no start situations.

I sucked the oil out of my HPOP reservoir one time in the 393,000 miles I have on my engine so far. I sent that oil to Blackstone labs along with a sample of oil that was drained out of my oil pan during a regular oil change. I did it because of all the discussions that came about after that misleading video that showed up on youtube. The lab found no difference in the oil out of my HPOP reservoir and the oil drained from my oil pan.

In my opinion, if you want your engine to last at least 400,000 miles, keep up with your maintenance, but don't waste your time changing the oil in your HPOP reservoir. If you don't believe me and think you have stagnant oil in there, park your truck in a place that you don't mind having an oil spill and remove the plug on the HPOP reservoir. Leave the plug out and start the engine. If it's slow to start, crank it for 30 seconds and then stop. You shouldn't lose more than a few gallons of oil trying this, but you can figure out exactly how much when you re-fill the crank case.

If you don't like the idea of the messy test and you're more of the book learnin type, we can discuss how the engine oil flows up from the LPOP through the HPOP reservoir. From the reservoir it either goes into the oil rails in the heads and is forced through the injectors before returning back to the crankcase, or is dumped back toward the crankcase at the IPR.

The stock 17 degree HPOP is a fixed displacement piston pump that flows 7.2cc's per revolution. The HPOP spins at 85% of the engine speed. So if we idle at 500 rpms (just a hypothetical round number) that means 500 rpms x .85 x 7.22 cc's = 3060cc's pm or per minute. If we do a conversion from 3060 cc's to quarts, that gives us 3.23 quarts per minute.

Now do the math at 2,000 rpm's and you'll understand why there are so many threads talking about not using oil additives because they can cause foaming oil.

With that kind of volume passing through the HPOP reservoir, do you really think it's necessary to change the oil in there?

 

Why yes, yes I do!

 

Well, I guess it's hard to argue with tin foil hat Bill.

 

That's funny!I'm on rep lock for 24 catch ya later LOL

 

I got him for ya!

Chris, excellent post! Very much the truth and well said Brother!

 

Chris- Thanks again.I am heeding your advice and leaving it alone.Seems like you are pretty smart on this diesel stuff and if it isn't broke-leave it alone. Pete

 

To protect groundwater that becomes drinking water and runoff water going into fish habitat please do not dump oil anywhwere but recycling pan.

 

LOL...that tinfoil hat photography majic is awesome!

However, before you go "knocking the HPOP reservoir change," don't forget Jody from DP Tuner has posted here that you should change it out every oil change, and I think a lot of people would respect his opinion. Yeah, it's only about 3/4 of a quart out of 15 quarts. But, why leave 6% old oil in there if you don't have to? It won't kill you to leave it in there (as almost everyone does), but it won't kill you to spend an extra 5 minutes sucking it out either.

If you don't believe me that Jody said it, here ya go (half way down the page, his #5 on the list):
https://www.ford-trucks.com/forums/1...l#post10585299