Hey I got a 1988 f250 4x4 with a 460. I seem to have an oil consumption problem. Iv'e put about 5 quarts in over about 1000 mile. There is no blue smoke and only a dime size spot of oil in the driveway over night. The under side of the truck is fairly clean. Anyone have a clue where the oil is going.

 

I d think that if its using tha t much oil that You would notice it going somewher e ..You got me !

 

What I have gathered is that the catalytic converter will hide the smoke from oil consumption. Are you towing, etc, making the engine work real hard?

Make sure your crankcase breather and PCV are up to spec.

 

I changed out the pcv, grommet and vacuum lines, they were shot. The vacuum lines alone saved me about 150 RPM's. As for the catalytic converter, I dont remeber seeing one, the guy who had it before me put headers on it and i dont think the converter was kept, not 100 percent sure though. Maybe the fixes will cut down on some of it.

Thanks bdhutch

 

You also have a breather line that goes from a valve cover over to your airbox. There is a little filter inside your airbox where the breather attaches. If this line gets plugged the pressure inside your crankcase goes wacky and oil consumption can result.

 

Ok, checked that. It had a few bugs in it but did not appear to be completely plugged. Also, Ive been noticing a lot of carbon build up on tail pipe with a lot of carbon in the water droplets from exhaust. Ive heard many things as to the cause of this carbon but not sure what to think.

Thanks bdhutch.

 

Holy cow man, I just checked the oil after checking that tube. It's down one quart after 68 frigin miles, yes "68" miles. I had a dime size spot on the driveway this AM. Have I got the wrong dip stick or what. This is stupid I cant see any signs of this much usage other than it being down. If the dip stick is wrong where did the quart go?

 

What do your spark plugs look like? If you're burning a quart in 68 miles, they will be oil fouled. Do you have one that is fouled while the rest look good, maybe indicating a stuck oil ring? Ring wear generally causes smoke on acceleration, while valves typically smoke on deceleration. Worn valve seals cause smoke on start up.

If you were leaking that much, you would have a whole lot more than a dime sized drop.....which leads me to believe you're burning it, even if it's not belching smoke like Mt. St. Helens.

There are only two things an engine can do to make oil disappear; Leak it, or burn it. It can't mysteriously vanish into thin air. Any chance it's leaking into the coolant? How many miles are on this engine? How much compression do you have? Did the previous owner rebuild it and maybe set the ring gaps together, or not hone a cylinder correctly?

Time to do some digging....and I don't think you're gonna like what you dig up. I'm betting your rings and / or cylinder walls are badly worn or scratched. The 460 is an incredibly tough motor, and maintained correctly, can go over 200K without major work. I'll bet the entire 48 cents in my pocket that either it has a bazillion miles on it, the previous owner(s) didn't maintain it correctly, or both.

Good luck to you. Let us know what you find out.

 

My mechanic said that my oil loss (about a quart every 200 miles) was due to a positive cranckcase pressure problem from an external vaccuum line. He explained that the pressure get very high inside the case when it is running, and that my tiny leaks can almost spray oil like a super soaker that has been pumped up. This is why I never noticed any oil spots on the ground. When the engine isn't running, the pressure is nil, so the minor leaks hold just fine. This makes sense to me, and the mechanic has it as I write this. The way I noticed this was that I was driving the truck home from Oregon to Nebraska, and coming through the cascades I started to hear a tap from the 460 and I got to the first rest stop and when I checked the oil, it was 3 quarts low. Luckily I had half a case on me. I topped it off and then every 200 miles when I filled the front tank, I had to put in a quart of oil. However, once I got into Utah just above salt lake city where the 84 meets the 80, I checked it and the oil was fine. I was back on the flatlands, and a lower elevation. The rest of the trip from Utah to Ogallala, NE I used only a quart and a half. That is about 700 miles. So, I guess a combination of the extra work climbing up and down the mountains through Oregon and Idaho put the pressure up higher, and the lower external pressure (Ambient) caused the oil loss to skyrocket. I am getting the truck back in a couple days and am going back to Oregon on the same road on the 25th of October, so I will let you all know if my mechanic and I are full of crap, or if this 460 oil loss issue is fixed. It sounds very close to bdhutch's problem, right down to the same oil loss rate.

 

fwiw, this engine is notorious for oil consumption. Mine has low mileage and still consumes 1qt/800 miles.

 

I was told that the dealers had warranty complaints and they wouldn't do anything unless consumption was greater than qt/500 miles. People will tell you anything, I have no idea if it is true.

 

OK finally got computer back up.
I checked all the plugs and found one that was badly fouled and another mildly fouled. After about 100 miles I checked the badly fouled again, it's now slightly fouled again. No dought this is where some oil is going, however still not convinced this is all of the problem can't believe this one hole is burning all that oil. I guess I may still have some other overlooked problems. Oh yeah, I checked for smoking on the freeway one night. When a car is behind me I can see clearly a blast of smoke comming from left exhaust upon excelleration and nothing from the right which kinda confirms the bad rings on left. Is is normal for rings to go bad one at a time like this? Iv'e heard of rings sticking could this be a problem, if so what to do?

 

resurrecting a dead post...

1990 efi f250 with 460, same problem... consumed 3.5 quarts of oil in 650 miles... all moderate - heavy towing. motor has no leaks, no visible smoke, though i do have a catalitic converter... plugs look good, compression is good!

Will try eliminating PCV system to see if this fixes the problem.

will post back results in a few months. (I dont use this truck very often... just to tow)

 

This sounds very familiar to me as I have a 1990 motorhome with the 460/C6 combo with U.S. Gear overdrive and it only has 44,000 miles on it but uses a quart of oil every 70 miles. Compression is 170-175 on all 8 cylinders and the leakdown test was good, so I put new valve stem seals in it and it still guzzles oil. There is no visible smoke from the exhaust but a very slight black carbon build-up in the tailpipe tip. I'm puzzled!! I will check the PCV valve and hose but am open to any and all suggestions.

 

I had a 5.4L E250 that would do the same thing, quart every few hundred miles. On a whim I decided to try that lucas oil stablizer stuff, went from a quart every few hundred to a quart maybe every few thousand.