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Prelude burning oil

I have a 94 Honda Prelude that I like a lot. It’s in great shape with only seventy five thousand miles
but it burns about a quart of oil every nine hundred miles. Is there a product or procedure that
could help this? Thanks!

(This is my first time on here, if you could send your suggestion to: moonphish@sbcglobal.net
as well I would really appreciate it!) I may not know how to find the answer…

You could try “high mileage” oil. It might help.

You didn’t say how many miles are on the car, but since it’s 18 or more years old I assume it’s a lot.

For a car that old, a quart every 900 miles isn’t bad at all. You could try high mileag oil, or bump the base weight up a notch, but the engine is tired. Nothing short of a total rebuild would stop it from burning oil, and I can’t see doing that in a car that age. Know that as long as you keep the oil level up the car will run indefinitely. It’ll never win any races again, but it’ll successfully get you from point A to point B.

Oil is cheap. Enjoy the car for hopefully a long time.

As mountainbike stated, the consumption of 1 qt every 900 miles is actually pretty good for a car this old.
How would you feel if you bought a new Audi, only to find out that the so-called “normal” rate of oil consumption (according to the mfr) is 1 qt per 600 miles?

Just be sure to check the oil level at least once each week, and change the oil according to the mfr’s maintenance schedule. And, if you change the PCV valve, it is even possible that your rate of oil consumption might decrease a bit.

@MB,

“It’s in great shape with only seventy five thousand miles…”

An additive product, “Restore” might help a little. 15W-40 oil is another path you might try…

Honda’s use an Alumasil block, no steel cylinder liners, the piston rings ride directly on the aluminum cylinder walls…Sometimes this can be problematic…

Thanks guys!! I was going to put some sea foam in and run it a few minutes before changing the oil. That’s how the sea foam reps said to do it. I could try restore too. Isn’t that the blue stuff that comes in the silver can? I think I heard click or clack mention it and did put it in last time.

My only other question is this and I think you already answered it. Is it OK to let it go down a quart each time before topping it off or do I need to check it more often? Thanks a million!!

You can try and additive, but don’t get optimistic. What you’re experiencing is simply nornmal wear, and it cannot be reversed.

It’s fine to let it go a quart down. The way the system works is that there’s a “pickup tube” sticking down into the pool of oil in the oil pan, like a straw in a glass of milk, through which the oil pump draws oil. The pump then pumps the oil through the lubrication channels cast into the engine. It isn’t until the level of the pool drops below the pickup tube that the engine runs dry.

It is a good idea, however, not to let the level get below a quart low, because even of the level is always high enough that the engine always has oil, the contamination and dilution that is a normal part of what makes oil go bad will have more of a negative effect in a smaller volume. A tablespoon of contamination is twice as bad in 2 quarts of oil as it is in 4 quarts of oil.

If the oil burning is caused from stuck oil control rings a half a can of Seafoam in the engine oil will sometimes free up the rings. If the oil burning is from worn rings/cylinders then a can of Restore can slow down/stop the oil burning. But DON’T use a 15W-40 weight oil. All that will accomplish is accelerated engine wear at cold starts causing the problem to become worse.

Tester

@DaveH may I suggest that you check and adjust the valve lash. I’m not saying that’s your problem, but at least it won’t be a factor.

Make sure your PCV system is clean and functioning properly…If the valve, hose or any of the fittings or vacuum port get plugged up, engine oil can be blown back into the air-filter box. Check the intake tube. It should be clean and dry inside, not full of oil…

I spoke with the Sea Foam rep. He said seven and a half ounces because the car takes about five quarts of oil, run it one hundred miles and change the oil. Some people said to spray some in the intake but I forgot to ask him about that. I’ll call him back today but it sounds fishy to me.

I don’t know how to check the PCV hose, fittings or port but they’res no oil in the air filter.

A '94 Honda Prelude with 75000 miles? I would look to drips and leaks before I’d look at burning. Her’s what I’d do: After driving it park it overnight and place a large piece of cardboard under the whole engine compartment. I betcha you’ll find a few leaks. 75k on a Prelude is really low miles (unless it was driven really hard and beat to death). My '89 Accord has almost 600k and uses less oil than that, but the majority is from small drips and leaks. After you see if you’ve got any leaks, post back. I went to 20W50 (Summers only) and it made a difference with my oil uses, which is BTW 1/4 to 1/2 quart every oil change, 3000 miles. Good luck! Rocketman

Want to sell it? Rocketman

The PCV (Positive Crankcase Ventilation) system is basically a check valve (one way valve) and a tube between the valvecover and a spot in the induction system. Due to pressure in the crankcase caused by blowby (small amounts of gasses passing the pistin and pressurizing the crankcase), hydrocarbon-laden fumes can pass up through the oil return passages and collect under the valvecover. The PCV tube allows these fumes to be drawn into the engine through the intake and burned with the fuel.

The PCV valve itself, a one-way valve, allows the fumes to pass into the intake, but does not allow anything to pass from the intake to the area under the valvecover. It prevents any backfire from igniting possibly volatile fumes under the valvecover, the combustion of which which would travel to the crankcase. Checking the PCV valve is as simple as removing it, inspecting it visually, and shaking oit to see that the piece inside that moves with the pressure is loose, as it should be.

If there’s a lot of oil residue in the tube and the PCV valve, it’s a pretty good sign that you have excess pressure building in the crankcase. That could be becaue the PCV valve is stuck closed and not allowing venting, or it could be excessive blowby pressuruzing the crankcase.

The PVC valve is located ring in the center of the valve cover on your engine. It is not likely to be bad, but they are cheap and easy to replace, just pull out and replace. I just replaced mine on out 97 Accord.

This engine is prone to leaks around the distributor shaft (just needs a new o ring, not a new distributor) and the oil pump. The oil pump can be taken care of the next time you have the timing belt changed.

What oil are you using? If you are using a 5w30, I would suggest changing to a 10w30. The 10w30 tends to not burn as much for engines with low oil consumption, doesn’t make much difference on engines with high oil consumption or on leaks.

Tester, question for you. While I am not recommending 15w40 for this case, why do you think it will increase wear? 15w40 is a diesel rated oil and contains anti-wear ingredients that have been found harmful to catalytic converters, but as anti-wear ingredients, many consider them superior to what is available in oils for gasoline engines. You have some new information?

15w-40 will not flow as quickly on a cold start.

A Diesel engine has a high volume high pressure oil pump. So it’s able to push the 15W-40 weight oil thru the engine quickly at a cold start. A diesel engine doesn’t go to a high idle when started cold.

On a gas engine the oil pump isn’t a high volume high pressure oil pump. And a gas engine goes to a high idle when started cold. So if the gas engine has a 15W-40 weight oil in it, the oil is too thick at a cold start for the oil pump to supply oil to the critical engine components while the engine is at high idle. And this accelerates the engine wear on a gas engine when it has a 15W-40 weight oil in it.

Tester

That would depend on how cold it is…Below say 20 degrees, 15W-40 may be a little heavy…But above that temperature, 15W oil flows easy enough to provide for the lubrication needs of worn engines…If the rings are shot or the alumasil block failed, 0w-20 oil will blow through it like water…15W-40 is simply compensating for an existing failure…