Is major oil consumption harmful to engine?

[Vronsky]

Car is using major oil. Have replaced valve seals with little result.
Don't want to spend big bucks on further repairs yet.
Is major oil consupmtion harmful to the engine?
According to manual, I can still ignore it.
But how about carbon build up? Where disappears all the oil to?

Cheers!

[Benzmac]

It cloggs up the catalyst.

[Mike Murrell]

Eventually your catalytic converter will clog up and that won't suit well with your engine mgt. or the local smog tester if you live in an area where that's required.

If it's getting past your valves guides, you'll certainly have increased carbon build-up in the head. If the oil rings on the pistons are not holding up, I suppose this could cause gradual wear on the cyl. wall(s).

Where's the oil going? Its' either leaking out or being consumed by the engine. A combination of compression test and leak-down test can indicate why it's disappearing if it's being consumed.

A visual inspection will give indication of a leakage problem. It's likely you have a combination of the two - leaking and consumption.

I realize money doesn't grow on trees, but if your oil loss is indeed substantial, you'll pay a higher price to correct the problem if you allow it to go uncorrected indefinitely.

My 2 cents.

I have to wonder what you mean by major .... Is this a gallon per thousand.. Quart per thousand????

Ken

[suginami]

Yeah, that was my question.

How much oil are you actually using internally?

[royaiii]

If you have replaced the valve seals, then someplace else is drinking the oil. Make sure you don't have a pressure leak anywhere. Excessive oil consumption will destroy everything from the headers to the muffler. Excessive oil consumption is tell-tale blue smoke. You better hope that it is not the piston rings because the engine will have to be dismantled almost completely. I wouldnt let it get past 1 qt per 750 miles. Perhaps, you should change to a thicker viscosity like 20W50.

[Vronsky]

If I do my calculations right (!) consumption is one quart on 1500 miles. Manual says the bottom limit is one quart on 600 miles.
Engine has no leaks, exhaust has no smoke whatsoever. No sign of any restriction in the exhaust (cat). Oil pressure on gauge is max. Engine has 98000 miles.
Mechanic thinks it might be the oil rings. Fixing this will be more expensive than the car is worth.

So that's why I'm wondering what will happen if I just keep on driving and pouring....

If clogging up the cat is the only downside: I recently learned that according to the law here, cars of my age don't need cats if they meet within the required levels without one. My guess is that it does. Really

Thanks!

One quart in 1,500 miles is not a problem except for the hassle of keeping it filled. If the consumption gets below the 600 mile level mentioned, then you will begin plugging up the cat and fouling spark plugs.

One of the beauties of a diesel is that there is no harm from excessive oil consumption except the expense and hassle of keeping it filled. There are no spark plugs to foul and since oil is fuel in a diesel, there is no harm. You can continue to drive a diesel as long as you can carry enough oil with you to get where you're going.

Good luck,

Quart in 1500 is not major oil use in my books...

I wonder if changing type of oil may not help.. I would think about using a diesel grade oil.. Lots of them are for all fleet use.. Meaning you can use them in gas or diesel engines.. Often those will clean the rings and slow the oil use.. The one I use for that is Chevron Delo 400.. an all fleet gas or diesel oil in the 15-40 grade.. It does a great job of cleaning engines inside.. I would change the filter in about half normal time the first time and see how it looks and make a couple oil and filter changes at 3000 miles.. see if that helps.. Not to much to invest if you figure the cost of doing other work..




Ken

[SCOTTFISH]

I am having the same problem on my 89 300 se. I have 181K on mine. I have had the valve job done. Mine was using about a quart & a half on a 800 mile trip. Driving around town, it probably would not use more than a half every 1500 miles or so. I am taking mine back in to the shop on monday. According to Chiltons guide on oil in on the spark plugs, the problem is usually either valve seals or piston rings. I have had the seals/guides checked since the job was done and they seem ok. My guess is going to be piston rings. You would think in removing the heads and tearing everything down that a machine shop or the mechanic would check those, but my guess is that they did not and when putting everything back together, the problem continued to exist. If someone else knows more than this, please respond. I only know what I have experienced and read, which may or may not be much help. Scott

A quart for 1500mi is not a problem and will not cause any problem neither. I would not spend a dime or loose 1/2 hour sleep over it. It is still well below what is considered as being an excessive oil consumption.
JackD

[Vronsky]

Well, had the valve seals replaced and, miraculously, oil consumption has almost disappeared A very happy guy, me.

There's a simple test, by the way, you can do to determine if its rings or valves that are leaking. Plug in a compression tester, and test every cilinder twice: first in the usual way, and a second time after adding a spoon full of engine oil in the cilinder. If the second compression test has the same (low!) result, the valves are the problem. If the second measurement turns out higher, the rings are leaky.

Good luck!

[manny]

Originally posted by Vronsky


There's a simple test, by the way, you can do to determine if its rings or valves that are leaking. Plug in a compression tester, and test every cilinder twice: first in the usual way, and a second time after adding a spoon full of engine oil in the cilinder. If the second compression test has the same (low!) result, the valves are the problem. If the second measurement turns out higher, the rings are leaky.

Good luck! [/B]

That would be called a " wet " test.