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Low on oil

I recently took possession of a car which has been run with a low oil level (for a lot longer than it should have been). The engine runs fine with no symptoms at this time, but it seriously worries me. Does anybody have any recommendations on additives or anyting else I can do before it gets worse?

About all I would tell you is to fill or change the oil and use it watching the oil consumption. If there is no loss of power, strange noises, and exagerated oil consumption, I would use it as is.

Don’t go out and waste any money on snake oil. If any damage was done it is done. Maintain the oil from this point on and hope for the best. Thats all you can do.

If it lasts longer than two weeks, the engine is probably going to be OK for a while. You really can’t predict how long the engine will last. How low it was could make a difference if it was more than two quarts.

It’s damaged goods to some degree and there is no additive in the world that will fix a mechanical problem.

If it’s been run very low on oil (as in the oil pump siphoning some air) then the overlayment of the bearings can be wiped away in seconds.
Eventually this loss of overlay is going to cause an expensive problem; as in engine rebuild or replacement.

Your best indicator is going to be when you start hearing a rapping noise in the engine when revved or the oil light starts flickering at idle.

Define “a low oil level”. Half a quart low? A quart low? Not on the dipstick?

And how long is “for a lot longer than it should have been”?

3.5 quarts low, holds 5 with filter. Unknown how long. My best guess would be that the level gradually decreased since last change at maybe 10,000 miles ago.

It’s on borrowed time.
At 3.5 quarts down that means it was sucking air because the remaining 1.5 quarts was in suspension (meaning it was filling oil galleys, pooling, and generally being thrown around inside, etc.).

Agree’if it ran any length of time with that little oil, bearings and other components would already be damaged. If the car is stopped virtually immediately when oil is lost, there will be little damage. I had this problem with a Ford when the oil fiter blew off and caused an underhood fore. Drove about 1/4 mile before noticing the smoke, stopped and put out the fire. The garage who towed the car in said there was 1 1/2 quarts left in the 6 cylinder engine.

After changing oil, no further problems showed up.

As ok4450 stated, this engine is going to die very soon. First of all, when oil is not changed for an extended period of time–such as 10,000 miles–it begins to break down and does not do a good job of lubricating. Because of the extended interval between oil changes, that oil also began carrying lots of contaminants and grit in it, and this exacerbated the poor lubrication situation. Then, when the quantity of oil is severely depleted–as in this case–the very small quantity of contaminated, broken-down oil begins to overheat, breaks down even further, coats the interior of the engine with “varnish”, and simply cannot lube the engine’s sensitive bearings.

If you are planning on keeping this car until it dies, I would suggest that you do the following:

*Check the oil level every 100 miles or so. The rate at which it burns oil could increase suddenly and…well, you know the probable result here.

*Do not take any long trips in this car unless you relish the idea of being stranded.

*Carry a cell phone with you and be sure that you have towing coverage on your insurance policy for the day when the engine suddenly quits on you. At least the tow truck can get you back to civilization, even if the engine can’t be saved.

How about having the oil pressure tested with a mechanical gauge while the engine is warm—this will tell you to some degree how much damage was done, as worn bearings will decrease oil pressure dramatically. Also, it might be worth pulling the valve cover and checking for sludging. When an engine is run with cheap/low oil, and very indifferent oil changes, that’s how sludge builds up. If there’s a significant amount of sludge in it, I’d pass on it as well.

Being an eternal optimist, I’m going to respectfully and partially disagree with my exceptionally knowledgable friends OK4450, Doc, and VDC on this one.

While running an engine low on oil will certainly reduce the life of the engine for the reasons described, if the level of the oil never went below the pickup tube (admitted the level it was run at makes this “iffy”) then the engine’s days may not be numbered.

I’d be inclined to drain it fully…including coolant since maintenance apparently wasn’t the previous owner’s forte…change the basics like tune up parts, filters and perhaps even the T-stat, and monitor everything carefully for awhile. Hey, you’re already in possession of the vehicle, you have nothing to lose by bring it up to snuff and hoping for the best. You might be surprized.

It might be fun and informative to do a used used oil analysis on the old oil and on the next couple of changes. It might tell you is the bearings are grinding themselves up.

I did not say the engine was necesarily toast, but that little oil in the crankcase will be mostly in circulation, and the pickup tube in the sump may be picking up air part of the time, resulting in dry bearings and excessive wear. If the oil was checked immediately after stopping the engine, some more oil may be present than indicated. But the combination of dirty 10,000 mile oil and the low level spells bad news.

However, I agree that with the benefit of the doubt, there may be some useful life left in the engine. Taking it out for a trip and frequently checking the oil level would be a good way to determine what damage had occurred.

And one should keep in mind that while most of the oil that is in the engine is in suspension the remaining oil in the pan is also subject to slosh; acceleration, deceleration, cornering, etc.
This means the oil pump pickup tube will be exposed to air at times and 4-5 seconds of an oil light is enough time for the thin coating of oil on the crank journals to be wiped away along with the bearing overlay.

Thank you all for answering. I have just registered it and started driving it after an oil change. I will just have to see how it does, since I am now the proud owner. Thanks again all.

Another satisfied CarTalk “customer”!!