Where's all my oil going?

mazda
mazda3

#1

So I recently had my catalytic converter replaced because it failed on me, I’m assuming because of the shear amount of oil being burned by my car. I go through an engines worth (4.5 quarts) in about a week. I’m pretty sure it’s being burned in the engine because there’s no leakage when car is parked overnight. I just replaced my spark plugs prematurely, and they were drenched in oil and burnt to the point where they look like white dog turds. Also side notes that may or may not be involved. After having the cat replaced, it tends to shutter very slightly when cruising in whatever gear. Car is 2004 but has 180k+ miles. So my guess is piston rings? If that is the case, anyone have a range of how much that repair would cost at a shop considering I don’t have the means to do a job that big myself.
Thanks!


#2

At the rate of oil usage your new Cat is not going to last long. You need: a complete engine rebuild, a used engine transplant or take what little you can get for this and replace vehicle .


#3

Was looking around the interwebs, could it be the valve cover gasket seals? Only 3 of the 4 spark plugs had oil


#4

When people talk about burning oil from bad valve cover gaskets, what they mean is that the oil is leaking outside of the engine, then flowing down and dripping onto the exhaust where the hot temperatures make it burn.

When a mechanic tells you the engine is burning oil, they generally mean it’s seeping past the rings inside the engine, and then going into the exhaust, rather than dripping down onto the outside of the pipe.

It should be fairly easy for you to determine which is happening with the rate of oil loss. If you don’t have a big puddle of oil under your car when you go out to it in the morning, you’re probably dealing with the latter definition, which means replacing the valve cover gaskets isn’t going to fix the problem.


#5

I’m referring to the gaskets on the valve cover that seal the spark plugs. Since 3/4 of the spark plugs I replaced were drenched in oil. Of course it could be that in addition to something internal since the electrodes on the plugs were severely burnt out too


#6

No, just No. The oil that would leak from the valve covers has no path into the engine’s combustion chamber to be burned. This car is either leaking past the valve seals (requiring what is termed a “valve job”) or it is going past the rings requiring at a minimum, new rings and honing the engine block for those new rings. A dry and then wet compression test will tell you which is the problem. At that point, it is like putting lipstick on a pig, pretty lips but nothing else looks good. At 180K, too much of the engine should be rebuilt to just do rings.

A rebuilt head for about $400 just for the head, another $400 or so to install.

A used engine is your best option, maybe you could get it for $2500-$3000 installed. A remanufactured long block is the next best option at about $2000 for the engine alone. Figure another $2000 for labor and misc parts. Is this car even worth $4000?


#7

Got it. Thank you


#8

With an engine using that much oil with that much mileage, try adding a can of Restore to the oil.

http://www.restoreusa.com/index.php

It’s cheap, and if it doesn’t completely stop the oil burning, it might slow it down.

What have you got to lose?

Tester


#9

How is restore different to Lucas Oil Stabilizer?