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Have a 93 f150 and after checking the oil at 500 miles it was 1/2 qt low well know every 500 miles it needs 1/2 a quart of oil? I cant find a leak anywhere and i park on concrete so i know if there would be a leak... is this engine just burning up oil? There isnt any rattles, knocking, black smoke or anything i can see or hear wrong..
1000 miles to a quart is no big deal in my opinion. It is likely going through the piston rings into the combustion chamber. You won't notice any smoke at that rate. If it was leaking through the valve guides you would probably see BLUE, not black smoke on startup. The only problem it could cause is it would plug the catalytic converter, but I don't think it would at that rate.
You could slow the consumption down by using thicker motor oil or adding a quart of Lucas oil stabilizer, but Personally I wouldn't at that rate.
How many miles on the truck? Which engine do you have?
One thing you might could try is running Marvel's Mystery oil in the motor oil.. I like a pint (approximately half of the recommendation on the bottle) or so in the last 1000 miles before you change the oil. Doing it like that for two-three changes back to back could help slowly clean up the motor. It significantly reduced consumption in my truck.. To almost zero. Rings can get coked up over time.
I would also change the PCV valve if its time. It could just be pulling it through the intake.
High mileage oils also may help reduce consumption if used consistently.
Hows the PCV valve, any signs of oil in the breather box?
Any signs of oil beyond the tail pipe? say for example stock tail pipe behind rear wheel. A oil coating all over the lower rear quarter panel, tail light and or tail gate? If so its a sure sign its not burning it but blowing it right through at a fairly steady rate.
A quart every 1000 miles is excessive even for a higher mileage engines.
I thought you couldnt switch from conventional to synthetic than back?
Yea you can switch back won't hurt anything.
Synthetics tends to be on the thin side, just too thin for some engines. Too thin for these motors? ehh maybe not when new or boarder line then but at 197K? yea probably much too thin.
Better off IMO using dino oil and a weight with some "body" to it to take up that space a little bit.
Alright good to know! And i braved the monsoon and went out to check the PCV.. tube is clear and the valve seems free.. i can shake it and it rattles and moves freely.. Also i noticed my i think it called breather tube that goes from the oil cap to somewhere is disconected? I assumed it goes to the air box but i didnt see a spot to plug it onto?
It will be at the very bottom of air box. Pull your air filer and you will see the rectangle breather filter. Synthetic oil is not "thinner" than regular oil. A 10w30 is just the same as conventional oil. It is however, slicker and penetrates better. This can also cause gaskets and seals to leak on older engines that didn't before switching.