If your vehicle is using a quart of oil every 1,000 miles, it might time to sell or trade in your vehicle. A vehicle using a quart every 1,000 miles is starting to show ware on the motor. 1,000 miles is still an acceptable amount for a quart of oil. The amount of oil use will gradually increase as you put on more miles on your car or truck. When you are adding a quart every 500 miles or less, it’s time for an overhaul.
Your engine’s oil consumption depends mainly on two things: the valve guides and piston rings. If the valve guides are worn, if there’s too much clearance between the valve stems and the guides or if the valve guide seals are worn, cracked, missing, broken, or improperly installed, the engine will suck oil down to the guides and into the cylinders. Even if an engine uses a lot of oil, the engine may still have good compression.
If the valve guides are worn, they can usually be replace at a mechanic shop. Knurling, sleeving or the guides and boring out the guides and installing valves with oversized stems will stop the loss of oil.
Oil can also slip past the rings if the rings and cylinders are badly worn or damaged. This may be that the cylinders were not honed properly when the engine was built or rebuilt or if the rings were installed improperly.
When a newly-built engine is first started, the rings require a certain amount of time to “seat” or break-in. If the rings fail to seal properly, the engine will use oil. In this case, the wrong finish was applied to the cylinders, which failed to clean and lubricate the cylinders properly before the engine was fired up, or the proper break-in procedure.
In some case, worn rod bearings, excessive bearing clearances and/or excessive oil pressure can slash too much oil on the cylinders, causing oil to get past the rings.
The cure for worn rings and cylinders is to overhaul the engine block. The cylinders have to be refinished and new rings installed to regain good oil control.
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