Oil change interval when leaking/burning oil

[Eric Urban]

I have a higher mileage car that loses about a quart of oil every 1000 miles. Previously I had a car that would lose a similar amount by burning it. Both cars ran well but they weren’t worth throwing money at. Since I was putting new oil in the cars so often the oil on the dipstick always looked great. Yeah I know “looks aren’t everything” and “it’s what’s inside the counts” 😛 but the oil always appeared super clean.

My question’s mainly theoretical. I know all cars are different, not every situation’s the same, etc, etc. I’m just after the concept as I like to learn as much as I can about what actually happens inside the various systems.

Assuming that the oil filter is changed regularly of course. My guess is that an actual oil change becomes less important if you’re leaking oil because most of the contaminants suspended in the oil would leave the system with the oil. Therefore the overall state of the oil would remain fresher with new stuff constantly coming in. But if you’re burning oil, some/lots of the contaminants remain in the system and the overall oil isn’t as fresh even though you’re constantly putting in new oil. It’s probably fresher than a car not receiving any new oil but not as fresh as a car that’s leaking.

Anyways, I’m hoping for opinions from people more knowledgeable/experienced than me. I’m always curious to learn new things. :silly:

Thanks.

Topic

[Jared Thomson]

I would say you still need to do regular oil changes. Because the detergent in the oil picks up crud inside your motor and suspends it, I would guess that the crud (I am using crud as a technical term 😛 ) is probably big enough that it doesnt make it through the rings into the combustion chamber. I would guess that you would have the same amount of crap suspended in your oil regardless of adding a quart every 1000 miles. If you time your oil changes right, you can change your oil right about the time that you would have to add more oil just to save you some oil.

[steven jacobsen]

My opinion is you could extend your oil changes a bit but draining is important, as I have been tought, light particles are cought in the filter but bigger particles (still tiny) are trapped in the pan. With the regular influx of new oil you are replenishing the additive from the oil, it is the junk in the system you want out.

[Eric Urban]

Couple questions…

1) Does the oil have to get to a certain level of degradation before it starts leaving behind deposits? Like say if you were constantly putting in new oil because you were leaking a lot would you still be developing sludge/varnish buildup?

2) Is an oil change mainly preventative maintenance or does it have a cleaning action in itself by “scraping” some of the buildup off the engine components as it drains?

I’m not trying to find a substitute for oil changes by any means. I’m just trying to get a better understanding of everything that goes on.

Thanks.

[Author]

Replies