I have an ongoing oil consumption problem in my 99 Accord (4 cyl). The car has 88k miles.

Yesterday I checked oil after the car was parked for about an hour (on a very hot day) and the level was below the lower mark. This morning I checked it again (the car was parked overnight, so the engine was completely cold) and the level was almost at the full mark, about 90% full. How is this possible???

There are no drip or leak marks under the engine or in the engine bay, last oil change dealer could not locate any leaks (oil pan seals, etc), so they asked me to start recording oil levels when I fill up gas. No signs of coolant in the oil or vice versa.


Any explanations for such fluctuation in oil levels? You would think that warm engine would show a higher level than cold engine.

 

It'll be sensitive to how level the parking spot is. The dipstick is all the way on one side of the pan. Can you park always in the same spot?

It'll be sensitive to how long since you shut off the engine. Not only the temperature but how much time the oil has to drain down from the head & everywhere else. Try to be as consistant as possible when you're recording oil levels. Maybe record oil level in the morning instead of at all the different gas stations.

 

Plus, don't forget, all that oil that runs through the whole engine, does take a while to drop back down to the pan

 

I would think an hour would be enough time for hot oil to come down. Does it take longer?

 

There's lots of places in the head for oil to puddle. But it seems like an hour is long enough. ???

Maybe the biggest reasons for the variation is oil temperature & levelness of the parking spot. It can take several hours for the engine to really cool down. Levelness side-to-side might be the biggest thing. Get your right-side wheels down (highly crowned street?) and it'll measure low because all the oil runs away from the dipstick.

 

This is why we test oil level 5 minutes after the car has been warmed and shut off, just like the owner's manual says.

 

I check my oil with the car in the garage after it has been sitting at least a day.

 

that's very wrong.

 

I used to have a POS Ford (which is why I now have a Honda) that did the same thing. Turned out the oil return holes were clogged and it took forever for the oil to drain back to the pan. Not sure if your Honda has a similar design/problem. Just a guess.

 

OK, but it's consistant. So why should the level keep changing?