Losing oil

I have been for the last three years searching for any signs and also completing repairs for lost oil on my '97 Honda civic. I recently ran Seafoam on my engine for about one hour and have yet to notice a loss in oil. The car normally loses about a quart every 4-500 miles. I cant explain this yet, I hope that this is the solution to my problem. Any explanations?

One hour isn’t a very long time.
You need to run the car for at least 400 to 500 miles before you see oil loss, according to your own words.

Also, I would recommend a compression test and an engine leak down test to search for reasons as to why you might be losing engine oil. Also, the valve stem seals might need to be replaced.

Check your car’s tailpipe for a big blue cloud of smoke on heavy acceleration.


How many miles does the engine have? What type of driving do you do, city or highway? How has the maintenance been?

Causes of oil loss are:

Passing by the oil rings. This can be detected often by a blue cloud out the tailpipe on heavy acceleration, however on newer cars the cat converter can catch a lot of the smoke so it isn’t as obvious as it used to be. It ruins the converter by coating the catalyst, but… The cause of this can be wear on the cylinders combined with tired oil rings (loss of spring tension, loss of pressure against the walls) or gummed up oil rings. Seafoam may help gummed up rings, but it won’t restore tired ones.

Passage by the valve stem seals. This can generally be detected by blue smoke on startup or on deceleration. The smoke on startup happens because after you shut the engine off the oil drains down out of the galleys in the head and if the seals are leaking some can drip by and sit on the backs of the valves waiting to be drawn into the cylinder and burned. The smoke on deceleration happens because when you take your foot off the throttle and it restricts the intake passage, the cylinders develop very high vacuum and can draw oil in the head galleys past leaky seals and into the cylinders…where it burns.

Leakage. By tired, shrunken, dried up gaskets and seals. Often the rubber seals at eth ends of the crank are the first to start.

A clogged or stuck Positive Crankcase Ventilation (PCV) valve that doesn’t allow the crankcase to vent, enabling pressure to build and force oil past tired, shrunken, dried up seals and gaskets.

Worn out cylinders combined with tired compression rings, allowing pressure from the cumbustion chambers to pressurize the crankcase beyond what the (possibly gummed up) PCV valve can vent…pushing oil past (see above).

You’ve tried ungumming the oil rings with the Seafoam. Now check the PCV valve, look for signs of leakage past seals and gaskets, and do a compression check. Post back with the result.

I have already completed every possible repair to include: leak down test, compression test, replaced valve seal stems, pcv system, crank and camshaft seals. The test that were conducted came back with a passing grade. After almost giving up and assuming that it could be the valve stem guides is when i decided to use Sea Foam. Again i havent lost oil yet. The car has 153,00 miles and it had been losing oil since about 60,000. I acquired the vehicle from my sister and her level of maintence was adding gas. I hope that my problem was gummed up oiler rings…

Have you replaced the PCV valve, and confirmed the PVC system is unplugged, and operating properly? A plugged valve or line could cause the crankcase to over-pressurize, and force oil leaks. This usually happens under driving conditions, and may not be apparent idling for an hour.

Also, there may be other seals getting ready to go. I had a troubling oil leak once in my truck for about a year. Then the head gasket blew. After replacing the head gasket, and a bunch of other upper engine gaskets, the leak disappeared.

Just a couple of thoughts.