oil consumption

[crm318]

i have a good running powerful 350 in my 72 cheyenne. yesterday when i was checking the fluid levels in it i noticed that i was a quart low. i changed my oil before christmas. the plugs are clean and there is no smoke in the exhaust. what could it be?

[bryanw1968]

Just because you don't see the smoke doesn't mean that you are not using it.
Could be blow by, valve stem seals or a leak somewhere.

[bobthecop]

Oil consumption is a normal by-product of any internal combustion engine. By manufacture standards 1 quart in 1000 miles is considered normal, however we all know better than that. How many miles have you driven since Christmas?? Oil type and weight also play a role. In my experience I have never been a complete quart low at oil change time, 3000 miles, but the level had drpooed some.

[67ChevyRedneck]

My Z71 burned an entire quart when I drove to NY (725 miles, and it was full when I left.) I was there a week and went through another quart. I checked my PVC and it was "sticking." Replaced it and it hasn't used more than an 1/16 quart in 2,500 miles... so far so good.

Also check for a leak: valve covers, timing chain cover and seal, oil pan, and worst of all would be a rear main seal leak (hardest to change.)

[brak]

could be as simple as a valve seal (probably notice a little smoke at startup after it's been stiing a while), or a minor leak someplace.

If the truck isn't billowing smoke, and you don't allow the oil level to get too low, I wouldn't worry about it too much.

Before i pulled the engine in my 84 camaro, it was using about a quart every couple weeks. I drove it this way for 4 years, across country, all over the place and had no issues. What finally did the engine in, was a bad waterpump, i probably could've driven the motor for a couple more years before i needed to address the problem

[Longhorn Man]

An engine that is not run much, or driven on only short trips, or has a misadjusted carb can also burn more oil than normal.

[piecesparts]

If your intake manifold gasket has just created a small leak (between the lifter valley and one of your intake ports, the oil consumption will be up and the motor will appear to be running normal and clean. I have a buddy that has been fighting this on his Corvette motor for a couple of years, since his last rebuild and we just found that the gasket had not sealed in one place. He would use a quart every 500 miles.

[crm318]

the motor is fairly new. it only has 30000 miles on and the heads were brand new s/r heads (completely new but doesnt mean that they could be leaking). The engine is acutally brand new from oilpan to carb. the truck is my daily driver and i drive it on long and short trips. i have about 600 plus miles on it since christmas. every thing seems to be tight on gasket wise. i also used a bead of silicone on the intake ends. there are also no leaks where i park. the truck runs extremely strong and shows no sign of being worn out. ill look into the pcv valve.

[pritch]

I don't know if you would have any around where you live, but if there is a freeway with a long hill on it, this is how I look for oil burning: Get up to speed or a little over and then let off and coast, in gear, with someone behind you with bright lights (do this at night) After a mile or two, put it to the floor. If you are burning any oil, it will show up in the lights behind you.

[fastwillie 696969]

the dipstick didnt shrink did it

[GREASEMONKEY72]

you should be able to rev it up sittin still and hang out the door so you can see the exhaust or have someone watch for smoke and if you have a tach it makes it easier to know where it is but i could rev mine and see the smoke come out but that was before i changed my valve stem seals now theres no smoke but goodluck with finding it

[crm318]

thanks for the tips guys. i do have a tach and ill try it out and let yall know.

[piecesparts]

DON'T rev to much in the driveway. This is the hardest thing that you can do to your motor. If you do this, it should be under a load. Doing burn outs is not as hard on a motor as doing it without the tranny engaged. When you let off that motor, the rods and crank are basically running without drag and causes a feedback to the engine frame. This is what destroys rods and the lower end.

[GREASEMONKEY72]

Originally Posted by piecesparts

DON'T rev to much in the driveway. This is the hardest thing that you can do to your motor. If you do this, it should be under a load. Doing burn outs is not as hard on a motor as doing it without the tranny engaged. When you let off that motor, the rods and crank are basically running without drag and causes a feedback to the engine frame. This is what destroys rods and the lower end.

ive never heard that before,i always heard reving didnt hurt it as long as you didnt redline it, but i will keep that in mind

[piecesparts]

I have a a couple of engine builders in my area, that sponsor the thought of revving the motor is bad, quite a bit. Taking a motor up with a load is no problem, just so there is something for that torsional torque to be absorbed into. Other wise the crank and the rods are the absorbers.

[clay68c10]

I'll second the intake gasket leak theory. I just resealed mine for that reason. If you have an aluminum intake and use the stock gaskets it may start sucking oil. Once it starts, it just gets worse.