My slant six is using about a quart of oil every 180-200 miles. I drive it 60 miles a day to/from work and I have to dump in about 2 quarts of 20W-50 a week. I don't know how many miles this engine has on it. It came out of a early seventies vintage car (Aspen I think) and I have it in a D100 right now. This truck sees very light duty, I don't tow or haul anything in it, and it still uses all this oil. It does smoke some on startup with the choke closed, but does not smoke after the choke opens and it gets warm. The oil pressure guage reads 45 pounds at hot idle, so it isn't really loose. I have looked around under it and I don't really see any huge leaks. What would you recommend? Should I pull the motor and put new crank seals and timing cover set on it? Davey

Small leaks shouln't blow that much oil--you'd see it all over the car. Oil smoke at start up is valve seals, but this much usage is probably rings.

Do check the PCV valve. And, check the oil: when the fuel pump goes, it can dump gas into the oil, which thins it and allows it to be pumped past the rings. If the oil smells like gas, change the pump.

Valve guides/ valve seals are leaking. Got nothing to do with the choke. The oil leaks down and colects and is burned out at start up. This will crud up your valves and put deposits on the seats and burn them out.

I am betting you have lots of small leaks. Mine leaks past the crank seal.

Check your oil pressure sender. They can cause a lot of loss fast.

Snug your oil pan with a 1/4" drive ratchet.

Do a little cleaning and see what gets oily again.

Valve cover leaking?

I had Ford 240 six that use oil like yours. It was the guides and the valve seals were cracked and laying in the bottom of the head. I redid the head and it quit using oil at 113K! Valve guides leak enough and you don't always get a lot of ring wear as they get "top cylinder lubed." LOL!

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'72 Duster 198 stock cam, 3:23's Hookers on jack stands for 8 years in the driveway
'79 Maxivan 360 Offy Qjet Comp RV cam/rusting in the driveway.
93 D350 160HP Cummins Auto Dually Clubcab needs a injector pump
2005 Golden Couch Buick

My first thought is the guide seals as well. I would also get a couple of cans GM top engine cleaner and run that through according to the directions. It will clean up the deposits and help loosen any rings that might be tight. The oil needs to be changed after you use this stuff. Also not changing the oil leads to oil burning, even if you are adding a quart a week. So first change the seals, run the cleaner through and change the oil. All the other advice about small leaks and checking for gas in the oil are good ideas too.

One other thing to try is a switch to a straight 30wt oil if it does not get too cold where you live.

One other thing to try is a switch to a straight 30wt oil if it does not get too cold where you live.

GM or Mopar combustion chamber cleaner, or Sea Foam. Or kill mosquitos with ATF I have used water the smae time I did the Mopar stuff.

Deposits will raise compression in severe cases (my 240 Ford) and have glowing hot spots that can cause preignition.

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'72 Duster 198 stock cam, 3:23's Hookers on jack stands for 8 years in the driveway
'79 Maxivan 360 Offy Qjet Comp RV cam/rusting in the driveway.
93 D350 160HP Cummins Auto Dually Clubcab needs a injector pump
2005 Golden Couch Buick