Weird oil usage

In December 2015, I bought a used 2015 Kia Soul. It had 29,000 miles on it. No complaints at all about this car. It’s been a good car for me. Right now, its got 130,000 miles on it.

My boyfriend checks the oil every morning. One morning when he checked the oil, it was way low, like 3 quarts low. The day before it was fine. No unusual driving was done. Happened again, all with routine driving. One day its fine, the next day its at way below normal levels.

A couple of weeks ago he replaced the PCV filter. We thought that would fix the problem.

About a week after, we made a 1000 mile round trip in this car. No problems at all on the trip. He checked the oil the next morning. All was good. Today, when he did his usual oil check, it was low again, about 3 quarts.

So what’s going on?

The only two choices that I can think of are 1- He doesn’t know how to check the oil or 2- You are a troll.


Who does that? 3 quarts vanish overnight ?

So because you don’t know an answer means I’m a troll? Only a jerk would bother to type a response like that. Please back out of this thread now. I’m looking for help, not name calling.


Are you seeing any black or blue smoke out the tailpipe? Any oil leaks on the ground? The pcv idea was a good one to check, as a faulty pcv system can suck a lot of oil out of the crankcase. But that would usually cause a lot of smoke out the exhaust pipe.

The 1.6 L engine uses a pcv valve, not a filter. I presume that is what your bf replaced. There’s a few tests to the pcv system that should be done. first, make sure all the tubing involved are free and not clogged w/gunk. look carefully where the tubing connects to the engine parts for gunk-clogs also. next remove the valve with the hose still attached and make sure you feel a suction at the other end when the engine is idling. next , with the valve completely removed from the engine, make sure you can hear a rattling noise when you shake it. finally poke a small-diameter object of some kind into the valve and make sure the plunger moves in and retracts back out again under its normal spring pressure.

It’s a legitimate problem that’s going on with my car. In fact, it was on the suggestion of a mechanic friend of his that he changed the PCV valve, which apparently didn’t work. And I didn’t say it happens over night. Since he checks the oil every morning and not at night when we’re done driving for the day, Maybe it’s something that happens while the car is being driven and not necessarily while the car is sitting overnight. There’s no oil on the ground.

And he checks the oil because the car has 130,000 miles on it and it’s usually driven about 150 miles a day. Who does that? My friend. Why does he do that? Read above

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Thank you for your response. My mistake. It was a PCV valve and not filter. Also there is no excessive smoke coming out the exhaust pipe and I never noticed oil spots on the ground. I’ll show him your reply. Thank you for your input.

Everyone with excessive oil consumption does that if they have half a brain.

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The only way I can see erratic oil level readings is if the oil drain-back holes in the head(s) are plugged with sludge.

Remove a valve cover and see if the top of the head looks like this.


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So the oil is getting pumped to the top of the engine and then sometimes it doesn’t drain back down to the crankcase b/c of gunk. Possible, but wouldn’t that cause the dipstick to show overfill sometimes too, b/c new oil is being added all the time, and if it comes back up after that, doesn’t that imply there’s a path open from the head to the crankcase?

Unless that excess oil is getting thrown out via PCV system on the increased rate?

I simply said the only 2 possibilities that occurred to me, I don’t know you and you don’t know me and you would not be the first poster to post bizarre symptoms to wind up the community. Maybe others will have more useful answers. I just can’t think of any conditions that will not cause oil loss on a long highway trip and then use no oil around town and then cause a random 3 quart loss in one day.

If you ever find out why, we would all be interested in hearing about it.

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Very curious problem. Fortunate that your boyfriend is so diligent about checking oil! Probably saved the engine from destruction due to the rapid onset of the problem.

How long ago did the problem first appear?
How many times has it happened now?
Is there any consistency to the timing between events?

You should make a habit of looking at the ground when you pull away from a parking spot to see if there is evidence of a leak. It may have a crack that shows up when something is hot and leaks. Is the underside of the car clean as in no oil blown back underneath?

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Here is an update. My boyfriend had changed the PCV valve at the time I posted here. He says the new valve rattled. He then disconnected the hose that is connected PCV valve. The PCV valve was sucking air consistently while the engine was running. The hose had no obstructions. He blew into the hose to see if there were any restriction or obstruction. Everything was OK. He then added a can of motor flush and then changed the oil and the filter. This was a week ago. He’s been checking the oil every morning and so far, there’s been no drop in the level. Fingers crossed. Thank you all for your input.


Good luck and please keep us informed.

Update - in checking the oil yesterday morning, the level had only slightly gone down. Today, quite a bit more but not as much as before. It’s as though changing the valve helped, but there’s still something going on. Baffled.

you have 130K miles on your Kia, that would explain a little bit of oil usage.
if it stays within reasonable, just keep checking the level and drive on.
replacing oil on more aggressive “severe schedule” should also help via better removal of possible sludge buildup.

Update - Since I last posted - We had to replace the gas cap. It was a standard one from an auto parts store. With that we noticed that the check engine light would come on and the fuel gauge would sometimes just stay on Empty although the car was just filled up. Eventually, it would pop up to the Full line. So everyday that it was started up, we didn’t know what to expect - sometimes no Check engine light. Sometimes the gas gauge stayed on E and we had to drive for a while before it popped back up. Most of the time everything was normal - as in no warning lights, etc. My boyfriend was still checking the oil level every day and had to add oil pretty often.

A few nights ago we were on a dark country road and the oil light would sometimes flash on even though oil had been added earlier that day, but the car continued to drive OK. We were about 20 miles from home in the middle of nowhere. All of a sudden the temperature gauge shot up and I pulled over on the berm. We had the car towed home. The next day, my boyfriend looked under the hood. The top mounting bolt to the alternator was loose. He tightened the bolt & the serpentine belt.

Problem solved. Oil level has stayed normal. No more warning lights on the dash.

Thanks all.

The loose bolt opened up an oil leak?