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Oil consumption

I have a 1999 Honda Accord. It consumes oil but is not leaking, the compression is good, and there is no sign of burning. What could it be? Might sludge result in the problem?

Oil can only leave the motor by leaking or burning, there is no other option. Pull your plugs, you should be able to tell which cyl is burning oil. How many miles on this beast??

All cars burn a little oil. You only need be concerned if it is excessive. Some is burned, and some leaks out through the seals. Oil can leak yet not drip on the cement, if it is a small leak. It just stays on the engine, in recesses and crevices, and eventually mostly evaporates. That’s why they make those engine cleaning solvents, to make the outside of the engine spic and span for those who like their engines to be spotless. (I don’t recommend this, as excessive cleaning of the outside of the engine can in fact cause leaks.)

Anyway, I assume you are loosing oil, but no drips on the cement. How much? Is it over one quart per thousand miles?

Define what you mean by good when referring to compression. The numbers, dry and wet compression test, etc.

I might add that it’s quite possible to have excellent compression and still have an oil burner due to seized piston rings; usually the oil control rings.

@ok4450, I’d guess if this car is burning oil, at this age, 1999, it probably wouldn’t be the piston rings. Unless it has been run really low on oil of course. More likely the valve stem seals are leaking. Replacing valve stem seals – if necessary – is done simply by removing the valve cover in most cars, and while it requires special tooling, it isn’t outrageously expensive.

To OP: Besides the suggestion to remove the spark plugs and look at them, another thing that is easy to do is took at the tail pipe. If there is a lot of oily residue at the end of the tail pipe, that can indicate some oil burning. If it is black – but not oily – just sooty-like, that usually isn’t indicative of oil burning. A sooty tailpipe is more often an fuel/air mixture problem.

Thanks to all. My mechanic says there is no sign of oil from the tailpipe. He insists that oil sludge is related to oil consumption without burning being involved, hence no tail pipe evidence or blue smoke. His idea is that if we can get rid of the gunk the problem will not be solved, but become fairly manageable. This sounds more than a little off to me.

How many miles per quart? I agree that sludge doesn’t sound right except if it’s caused you oil ring to seize like OK said.

Does The Car Have A PCV Valve ? Did The Mechanic Check The PCV System ? While Checking The PCV (Positive Crankcase Ventilation) System For Free Flow, Replace The PCV Valve If It’s Relatively Inexpensive Or Questionable.

Oil use is tolerable if you get on a schedule to check it regularly and add it when necessary. I never let a car get more than 1/2 quart low. Write down the miles driven each time you add a 1/2 quart or quart so that you can monitor it and make sure it’s not getting worse.

How many miles are on this little beauty ?
How much oil per how many miles of driving, approximately ?

CSA

100K miles, not a lot for a Honda. I have been checking oil. It will drop 1/2 1 qt in a 1000 miles, sometimes less.

Is That A Half Quart Per 1,000 Miles Or Less ?

CSA

This Car Averaged Only About 7,000 - 8,000 Miles/Year. Sometimes That Is Almost As Hard On An Engine Than Excessive Driving.

Does/did the car make/made lots of short trips of just a couple of miles ?
Has the car ever had long periods of sitting without being driven ?
How has it been used during that 100,000 miles ?

CSA

All short haul stuff. A few miles at a time. Yes, per 1000 miles or less.

All short haul stuff. A few miles at a time. Yes, per 1000 miles or less.

That is hard on a car.

Although Having A Car That Consumes Oil Isn’t Ideal, A 1999 Vehicle That Uses A Full Quart Of Oil Every 1,500 To 2,000 Miles Isn’t Out Of The Ordinary.

Manufacturers of cars vary with their definitions of excessive oil consumption, but most consider excessive to be more than a quart in a range of 1,000 to 2,000 miles on brand new cars.

As cars age and/or accumulate miles it is fairly normal for them to use more oil than when new or newer.

The important thing is to not let it ever get low (more than a quart low) and monitor the consumption so you’ll know when it possibly will be low. Checking all car fluids on a regular basis will work well. Most Owner’s Manuals admonish the owner to check oil at each gas fill-up, even when the car is new.

CSA

This engine is not prone to sludging up so I doubt that is the problem. They do however, leak like a sieve, but the leaks can be hard to detect. The oil seals at the front of the engine sometimes leak, as does the distributor shaft o-ring and also the oil pressure sending unit.

Have you looked at the bottom of the engine? I’m pretty sure you will see wet oil down there, maybe even a fully formed drop ready to fall. Also look under the distributor. This is an important area to check as the oil will drip onto a heater hose, it will swell up and start leaking coolant, then you will have a real problem.

A consumption rate of 1 quart in 2000 miles isn’t worth worrying about. There’s something a little wrong probably, but it doesn’t make much economic sense to spend much trying to figure out what. No harm, no foul.

If it gets to more than a quart in 1000 miles, then it might make sense to get a mechanic involved in a diagnosis.

If this were my car, I’d simply bring all the routine engine maintenance up to Honda’s specs (i.e. the owner’s manual recommendations) and say ‘good enough’. I wouldn’t get involved with any engine cleaning schemes. If you think the engine isn’t clean enough, just change out the oil and filter more often.

I really don’t think you have a problem, but you might try a different brand of oil. Use the same viscosity recommended in the manual for the car–just a different brand. I had a 1971 Ford Maverick that used a quart of oil about every 1200 with Sunoco 10W-40. I got Valvoline 10W-40 on sale and decided to try it. The Maverick would go 1500 miles per quart.

Less than 1/2 a quart every 1000 miles? Don’t worry about it. You keep mentioning that your mechanic is suggesting a sludge issue . . . does he/she want to de-sludge it? Sounds like someone wants to do an engine de-sludging and this can cause more problems than it solves. If it were my car I would change the oil change interval (lower it) for two or three changes, then live with it. The extra oil changes will help with any sludge (if there is any) and really 1/2 a quart per 1000 miles is NOTHING. If it bothers you, have the mechanic pull the valve cover of and look at the skudge . . . take a picture with your phone and post it here. I’d like to see what the sludge looks like. Valve cover comes off in a few minutes, easy-squeezy. Enjoy your Accord! Rocketman

"My mechanic says there is no sign of oil from the tailpipe. He insists that oil sludge is related to oil consumption without burning being involved, hence no tail pipe evidence or blue smoke. His idea is that if we can get rid of the gunk the problem will not be solved, but become fairly manageable. "

“Manageable”? You don’t have a problem to “manage”. 1/2 quart every 1000 miles for a 13 year old car with 100,000 miles is NOT excess oil usage. It is perfectly healthy.

I’m uncertain by reading the thread whether it was you or your mechanic that became concerned about oil usage.

If it was you, he may have been only trying to comfort you. You can rest secure in the knowledge that you have no problem. Just monitor the oil as you have been and you’ll be fine.

If it was your mechanic, get a new mechanic. He’s trying to sell you something you don;t need.

I’m still not sure about the OP’s oil consumption.
@Jaam - How many miles per quart? 1,000? 2,000? 667?