Using a lot of oil

MH47Wrench · Nov 7, 2016

What would cause my 7.3 to go through up to 6quarts of oil over the course of 300 miles?

2002 7.3 179k miles, ts chip running on 'standard' setting. Not driving the truck hard or towing anything. I hauled my 8400lb 5th wheel 300 miles without losing a drop. Don't haul anything and I lose 4-6 quarts. Bought the truck this summer with 177k and have already replaced the injector o-rings. Running Rotella.

DEEZUZ · Nov 7, 2016

Any smoke out the exhaust? How is blowby when hot/cold? Have you rechecked the fuel for Oil?

MH47Wrench · Nov 7, 2016

Slight amount of blue smoke on startup. Might last 10-15 seconds. Not sure how to check for blow by.

Magnum PD · Nov 7, 2016

Take the oil fill cap off. Do you see a lot of pressure coming out of the tube?

gnxtc2 · Nov 7, 2016

Fuel filter black? Pull DP off or check for oil in exhaust for blown turbo seal.

Billy T.
[email protected]

Strokersace · Nov 7, 2016

Did it start using oil after you replaced injector o-rings? If so, as Billy said, your fuel filter will be black. And you have a bad o-ring or several.

MH47Wrench · Nov 7, 2016

Noticed the heavy oil usage a couple weeks after I bought it. Went to change the oil and only about 7 quarts came out of the engine. Kept an eye on it for a couple more weeks before I changed the injector o-rings. (The o rings on #7 were shot). Put it back together and everything was fine for a while. No oil on the ground. Outside of the engine was clean.

DEEZUZ · Nov 7, 2016

Eh. Not where oil would mix though

gnxtc2 · Nov 7, 2016

You check the turbo?

Billy T.
[email protected]

TARM · Nov 8, 2016

Well the oil has to go somewhere and @ 6 qt in 300 miles thats ALOT of oil.

Go thru the normal checks:

Color of coolant? Any oil?

Exhaust has already been answered that little blue is not nearly enough as it would bellowing smoke for that much oil.

Fuel - check fuel filter ( at least your injectors would be getting plenty of lube if this is the case LOL)

Blowby- fully warmed up engine pull the fill cap and see if its smoke is floating out or puff puff puffing out. It would blow the cap off if you sit on upside down. Not vibrate off but blow off. You can feel it on your hand.

Check the turbo fittings and inside. Pull the hose off the intercooler and see what comes out.

MH47Wrench · Nov 14, 2016

Finally had time this weekend to do some checking. No huge puddles on the ground. A couple drips under the oil pan, maybe the size of a half dollar. Coolant looks perfect, fuel bowl doesn't show any signs of oil. Fuel filter is a little dark but not black. I suppose I should consider all of this good news in some sense.

Let me pose this question and see if anyone has an 'ah-ha' moment:. When I did my injector o-rings, I hydralocked the engine. (Grand moment of stupidity on my part). I only tried cranking it a couple times before I realized what was going on. I pulled all my glow plugs and turned the engine over 3 or 4 times with a socket on the crank pulley. Put my glow plugs in and everything was good. Here we are months later and it is hard starting when cold. I let the glow plugs cycle and hit the key. Most of the time i get a single 'click' like the battery is dead. If I immediately try the key again it might start on the 5 the try. Once it's running everything runs great. If I try to start it warm, it takes right off. To say I'm stumped would be an understatement.

DEEZUZ · Nov 14, 2016

Well, with the new information, Id do a hot/cold compression check, then a cylinder leak down. You might have compromised rings/rod pending on how hard of a hit it took when hydrolocking

TARM · Nov 18, 2016

But then it should not be ok once its started even cold. Sure as it warms up that changes things but if I am understanding correctly its only starting it the initial time and only in the cold.

Would an issue with the injector cups create an issue? If its losing oil and its not from a leak at the normal external places I tend to question injectors hpop.

How does the valley look? It is dry. See if you can trace out the path down the rear if you have a leaking hpop.

Have you put a scanner on it while cranking? Would like to see what kind of ICP etc..

I have always wondered about hydrolock damage on a engine that does not fire up at all but is only cranked by the starter. The force can only be that of what the starter can apply and then the lever affect of the flywheel radius. Hell most of our old starters seem to barely have enough tq to get these 7.3 turning over in the cold. Compare to say the force of the cyl pressure @ say 1000ftlb

I guess I could stop being lazy and work the math. Say its a 200 ftlb for starter at the gear. flywheel is what 12-13" diameter so half that or for easy math 1/2 foot. SO we work it just like adding an crows foot or similar to a tq wrench. half a foot would increase it 50% so 300 ftlb tq. Compare that to force the CP inside the cylinder puts on the rod and crank at peak TQ. Not sure I can see that bending a rod. Now if a cylinders were firing and it locked up that would make a mess.

I could also be way off here in my calculations. But I can not see how a starter with a maximum stall tq of 200ftlb even with the leverage from the flywheel length(so 300ftlb) could bend a rod on a engine capable of putting more than that at the flywheel in stock config.

Someone that knows please correct me if I am way off. Above is more a question looking for confirmation than anything.

superpsd · Nov 18, 2016

I highly doubt it bent a rod. It's possible you have a shot internal Intensifier piston oring(s) and you have oil bleeding into the barrel and being injected as fuel hence no signs of oil leaks. It does happen from time to time.

TARM · Nov 21, 2016

superpsd said:
I highly doubt it bent a rod. It's possible you have a shot internal Intensifier piston oring(s) and you have oil bleeding into the barrel and being injected as fuel hence no signs of oil leaks. It does happen from time to time.

That would make sense and would explain much of it.

How many miles are on the injectors? OR I guess the truck if you do not know if they had been replaced?

DEEZUZ · Nov 21, 2016

alooooot of oil to burn and not see smoke

TARM · Nov 26, 2016

Thats why I have trouble understanding its not on the ground somewhere. It either has to go in the coolant out the tail pipe or on the ground.

I was thinking maybe a hpop or turbo associated leak that is only dumping oil while its running but I would expect it in the valley and at least some on the ground

lincolnlocker · Nov 26, 2016

TARM said:
Thats why I have trouble understanding its not on the ground somewhere. It either has to go in the coolant out the tail pipe or on the ground.

I was thinking maybe a hpop or turbo associated leak that is only dumping oil while its running but I would expect it in the valley and at least some on the ground

yeah, that is a crap load of oil to not either see it pouring out or see the oil haze out the pipe..

live life full throttle

god bless america and the farmer who feeds your fat ass