I have a 1989 model F-Superduty (F450). It has relatively low miles (Odometer says 99,000-its probably 199,000, but the title says exempt because of age). I just bought it and on the trip home (300 miles) it burned 11 quarts of oil. I had a mechanic look at it, and he claims that there is nothing wrong with it other than that it is geared extremely low. The oil didn't leak out; it burned out. I was running the truck 65-75 mph down I-95, and the mechanic says that it is built to be run no higher than 50-55 mph. Is this a reasonable explanation for that much oil to be lost? I would appreciate any insight that you guys can provide.

 

With that much oil being burnt it has to have poor rings in it! If it's not leaking anything (oil pan) then I would try testing the rings with a compression test. An easier test would be to start it up pull the oil fill cap off and if you notice a lot of smoke thats not good. Check your air filter/breather to see if that it oil soaked as well. 11 qts is quite a bit of oil I think!!

 

It does smoke a good bit from the oil fill hole when the cap is removed after the truck has been running a while. What would that be? I assumed that it was just where the oil was hot.

 

Sounds like that mechanic is full of it. Man those rings are shot. You almost burned 3 GALLONS of oil on a 300 mile trip. That is not good!

 

Thats what I was thinking! Bad rings = Burnt oil (blowby) Not much you can do to fix it with out tearing down the engine. You can try a can of oil addative and that might help slow it down, or even run a thicker weight oil. The down sides is loss of power and having to watch your oil more closely, other that that drive it till it dies!

 

The oil that I was putting back in it was 15W-40, so I figured that was pretty heavy duty. It's up for sale right now. I want to keep it, but I need something to pull a loaded 32' livestock trailer with. If you think of anything else that I can do without having to get rid of it, I'd appreciate it. I cant afford a tear down right now, so I don't really know what to do.

 

You might find an engine to swap at a decent price. Check the junk yards, online, etc.

 

Matthew, is the rest of the truck in good condition and safe? Rust, front end steering trans, all good etc. And you say you just bought it and it's now for sale. I would pull all the spark plugs, evaluate each one and see exactly what's up in each cylinder, plus run a compression test etc. Are the rear end gears that low that it ran at very high RPMs for 300miles. if not that oil useage which is obvious was really excessive, for sure there's trouble. There is a product called "ring-free" which is used in marine engines, if you have a frozen ring, not broken, who knows maybe this will free up the rings and something will improve. If the rings are broken or just shot it won't do anything I don't think. Also a good additive like Lucas might help. If it's a good solid 450 it might be worth the hassel until you can get into the motor. Sorry to hear your troubles, sounds like a pain in the butt. Good luck.

 

Also I should add, look carefully in each spark plug hole with a small bright light so you can see if any thing looks like broken pieces in the top of cylinder, or if its wet with oil or whatever. Also if one of spark plugs is smashed on the tip. A lot of this stuff is just to give you a better idea what's really up. Sounds like mechanic isn't too sharp, but in fairness, he actually saw the truck, we on the website didn't.

 

Thats a lot of oil to burn, you would have noticed a large fog behind you. I once had a fire truck pull me over when my girlfriends Passat blew the turbocharger. They thought the thing was on fire. lol.

 

Is there any evidence of oil on the bottom of the engine and tranny ??

I ran into a strange phenomen with my 94 with a 302 which I bought last spring.
It always dripped a little oil when parked and I saw oil all over the bottom of the engine and oil pan and thought I had bad main seals. After gunking it down, I noticed several leaks on the pan about a third of the way up from the bottom. I cleaned them well and JB-Welded them. At this time I also noticed that the oil pan gasket was kind of bulging out and evidence of silicone at the seam in areas where the gasket appeared to be completely squished out of the seam.

I drove it around town for several weeks and kept checking for oil on the pan again, but it stayed bone dry and I never lost a drop of oil. I drove it up down some pretty steep grades.

A few weeks later, after driving on the freeway at 65-70, I noticed oil leaking again. I blew it off with a hose and it stayed dry again.

What I have come to assume and understand is that my pan has a squished out gasket in places, and oil is constantly being splashed on the inside of the gap at the top of the pan which then runs back down into the pan. However, when on the freeway traveling 65-70 it is being drawn out of the gap to run down on the outside of the pan by the force of air traveling under the truck at those speeds.

If there is evidence of oil on the bottom of your pan, this could be your problem too.

 

When I checked under it, it appeared that there was something leaking around the transmission. The reason I stopped the truck on the highway initially was because I smelled something burning and the cab filled with smoke. When I got out and got under the truck, I could see the oil or whatever it was around the transmission. I figured that maybed some oil had leaked out and gotten on the exhaust. The smoke and smell got better but never completely went away. I parked it overnight at a truckstop and the next morning there wasn't a drop of oil under the truck. I had someone follow me home, and there didnt appear to be anything leaking under it while driving. The person did say that they could smell the oil burning while riding behind me.

 

If it burnt that much oil it would be smoking like a freight train out of the exaust.

 

from your last post it sounds like your rear main, if you actually burnt 11q's of oil I would think the plugs would be too fouled to run properly ( I had a truck that used 19q's in 650mi and I had to pull over and clean the plugs several times)