Missing oil

[Badd00SS]

I have a very peculiar problem happening to my bobcat 225.

twice, I have run it for about 10-12 hours of total use, and it has gone through 1 full qt of oil each time. Here is the odd part, there is NO blue smoke, or smoke of any kind, and there is no puddle around/in/on the welder.

I have never seen anything like this. I mean, I figure an engine could consume a small amount of oil without noticing it but 1 qt in about 10 hours?

Its an onan p216 Really confused on this one....

[griff01]

Make sure the breather tube is intact.

Griff

[stronics]

For what it is worth, I have last year, run the same with the same oil consumption problem. I didn't see any smoke either but there was quite a bit of oil around on the engine. Not as much as that which was gone but some.
Tank of gas, qt. oil go figure.
David

[Aerometalworker]

I have a very peculiar problem happening to my bobcat 225.

twice, I have run it for about 10-12 hours of total use, and it has gone through 1 full qt of oil each time. Here is the odd part, there is NO blue smoke, or smoke of any kind, and there is no puddle around/in/on the welder.

I have never seen anything like this. I mean, I figure an engine could consume a small amount of oil without noticing it but 1 qt in about 10 hours?

Its an onan p216 Really confused on this one....

Seems a bit excessive doesnt it? Although it may be ok. If you pull the spark plugs do they show signs of oil consumption? Burning 3 oz per hour at that fuel consumption wont cause much noticable smoking. Is this something recent or has it always used this much oil?

[Badd00SS]

Seems a bit excessive doesnt it? Although it may be ok. If you pull the spark plugs do they show signs of oil consumption? Burning 3 oz per hour at that fuel consumption wont cause much noticable smoking. Is this something recent or has it always used this much oil?

I have only had it for about 4 months, its an old machine, and it just started doing it, I hope its not the end for her...

Spark plugs look normal, thats whats weird.

[Aerometalworker]

I have only had it for about 4 months, its an old machine, and it just started doing it, I hope its not the end for her...

Spark plugs look normal, thats whats weird.

I take it its running fine, making good power and such? Sometimes air cooled engines have issues "gunking" up the oil control rings and oil return holes in the pistons, this can lead to oil consumption at power, but no smoke at start up. Multigrade oils are worse for this. You can try Marvel Mystery Oil added to the oil at the next oil change to help disolve the gunk. Also switching to a single grade oil is of help.

[Winger Ed.]

Hmmm,,
A quart in 10 hours?
If it was a car going down the freeway, at what do ya figure,,
Taching say,,, 3,000 rpm or so, that'd be-- oh,, something around 80mph?
It would be burning a quart in more or less/about 800 miles.

Its a smaller engine, but you get the idea.
Depending on how old & worn it is, that may be sort of normal 'wear & tear'.

Anyway, as to where the oil is going:
The crankcase vent could be sucking it in and burning it if the rings are just starting to wear enough for ya to be getting blow by gases; but not worn enough to really smoke. After awhile- it will foul the spark plug.

Another possibility is the sealing ability of the exhaust valve guide.
When they wear, oil from the top of the head gets on the valve stem,
but isn't wiped off when the valve opens. The oil on the valve stem gets burned as the exhaust pulse goes past it. This oil consumption won't show up on the spark plug, but will start making a deposit on the exhaust valve stem in the port between the top of the valve & the head.

If it was me,
I'd check the oil level every 3-4 hours.
Maybe go to a little bit thicker oil.
Change it every 40-50 hours, or sooner if it says.
And just run the thing until it gets to be a real problem.

.

[FM117]

How many hours are on the engine?
That's the big question.
Any sign of oil in the airbox/aircleaner area?
Dave P.

[Badd00SS]

Thanks guys, I'll try switching oil first....

It has 672 hours on it.

I'm going to keep my eye on a pipeliner around the corner from me in the meantime.... He had it for sale, and then took off the market...

[Tom C]

I had an exact same unit years ago .......... Onan is a nice motor......... Here's the thing.........My dodge truck does the same thing..........to go thru that much oil ........ ya gotta have a small leak some where.........take a better look that motor it can't be buring it ......... past weekend my neighbor asked me to look and see why her garbage disposal wasn't working........put the socket down the inside and NOPE can't turn .........????????? then she said the carpenter put new front inlays above the sink............DUUHHH.......I said maybe he droppped a screw in the sink .......... 2 hrs. later after I took it apart......GD 1 1/4 " drywall screw in the blades ......... works fine now