Oil light comes on intermittently but the dip stick was bone dry

We have a new to us 2005 Subaru Forester and my husband is the usual driver. It’s important to note he has a history of not taking care of his cars and trucks. We have this vehicle because we needed something ASAP when he basically drove a GMC Sierra into the ground and due to little routine maintenance. This is one of my biggest issues with him though I do still love him :slight_smile:

I drove the Subaru two days ago and noticed the oil light came on intermittently usually at stop lights. Today I took it to auto zone bc I checked the dipstick and it was dry. I thought I can’t be right, I must be doing this incorrectly. Sure enough the guy at the auto parts store confirmed it was totally empty. My husband isn’t super clear about how long this might have been going on. (I’ve been texting him while he’s at work and not getting an answer which sort of tells me what it need to know)But regardless I’m wondering why is the light only on intermittently if it had no oil. Wouldn’t be on and stay on as a scream for help?

I made an appt with our trustworthy mechanic but it isn’t for two days. I have extra oil to pour in in the meantime. What are some possible causes and costs?

If you fill it up with the proper amount of oil, and the light stays off, not much more you can do. I would recommend an oil change in the near future. It uses oil, check often and see how many miles per quart.


The engine is either burning the oil or the oil is leaking somewhere. Those are the only options. Your mechanic can hopefully determine the exact cause.

I’d fill up the crankcase to the appropriate level with the correct oil ASAP. Don’t start the engine again until it’s got the proper oil. Not even a short trip. You’re likely on borrowed time now.

It sounds like you already know this…but it’s vital that you or your husband check the oil on a regular basis. 5 minutes of your time on a Saturday morning might just save you having to buy a new engine.


The traditional oil pressure light does not come on until it’s out of oil.
Imagine a spray paint can when it hits empty.
It works fine until it suddenly sputters and wheezes out gas and no paint.

Why did this happen?
A combination of two things.

  1. Subaru is a brand with motors that frequently consume some oil.
  2. Even the average driver does not check oil level as often as they should.

Most car makers recommend checking oil level every tank of gas.
Once the rate of oil consumption is known the interval between checks can be stretched out.
But no longer than 1000 miles, IMHO.

If the engine runs OK and doesn’t make knocking noises I say drive on and cross fingers.

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the light is likely intermittent and comes on at stoplights because the oil level is right at the sensor level- so when you accelerate or stop, the oil level moves just enough to trigger the sensor. add oil, start checking it more regularly, and drive on.
and either start saving for a new car or a new engine. You’re gonna need one if hubby won’t check his car out or keep up with normal maintenance.

The owners manual will tell you if this is an oil level warning light or one for oil pressure. Some cars have both.

If there’s no oil showing on the dipstick, it does not mean there’s no oil in the engine. There may be oil, but there is not enough.

It’s wise to check the oil level often especially with a car that’s new to you, and if it’s below the full mark on the dipstick, add enough oil to bring it to that level.


The bottom of the dipstick isn’t all the way down to the bottom of the oil pan. There can still be some oil in there after the oil drops below the dipstick. That’s why the dipstick was dry even though the light wasn’t on full time.

The light isn’t hooked up to a level sensor. It’s hooked up to a pressure sensor. That’s why it blinks on and off at stop lights. When you stop, or go, you’re sloshing oil around in the pan. Usually that doesn’t matter because there’s plenty of oil in there, but if you’re really low on oil, you can slosh what’s left right away from the pickup tube that sends the oil to the engine. That momentarily drops the pressure and turns on the light, and then when the oil sloshes back and the pickup tube sucks in more oil, the pressure goes back up and turns the light off.

As for your husband, if he’s going to insist on being irresponsible with his vehicles then you’re going to have to take over for him unless you want a lot of your money to be going toward car repairs and replacements.

Maybe you should be checking his oil level once a week, and in return make him do some chore that you don’t like. :wink:


Thanks for this. This was my thinking too. Maybe there’s just barely enough to keep the engine going but not where it should be. I added three quarts and it’s on the lower end of normal now. I will monitor

The oil level needs to be at the full mark and check it at least once a week.


There is still some oil in the engine even if the stick is dry. The on-off oil light could be due to the remaining oil sloshing around in the oil pan. When it sloshes against the pickup tube it inhales enough oil to turn off the light but that does not mean much.
It only takes about 3 to 5 PSI of oil pressure to turn off the light. That is not enough pressure to protect an engine.

Driving it with the oil light on and little oil in it is a huge mistake. I sincerely hope that your husband does not lay the original problem at your feet. Since your hubby is the usual driver it’s on him to check under the hood rather than assume things are fine.

Odds are the engine is burning oil and it was likely doing this before you bought it. This generally means piston ring problems and that is expensive to fix.
What your mechanic needs to do is run both a dry and wet compression test on the engine. A good engine should put up numbers like 185 PSI, etc. If a number is low (say 140) during a dry test and it goes up to say 175 during the wet test then this means a ring problem sad to say.
Another pre-compression test is to connect a vacuum gauge which will give on a feel for the general health of the engine. A healthy engine should have 20 to 21 inches of mercury. Down around 15ish or so and next step is the compression test.

Someone in your household MUST get into the habit of at least every other week raising the hood and checking all of the fluid levels. Failure to do is going to lead to the catastrophic failure of (fill in the blank). Best of luck.


Wow. It’s probably still a quart low and your Forester has an oil capacity of about 4.5 quarts, so there was only about half a quart left. You have my sympathy, my wife killed a Jeep Liberty after I inherited it by doing the same thing. I added 3 quarts of oil more than once. These days I go out late at night when she’s in bed and check the oil in her Hyundai. At this point that’s about all you can do.

You put oil in? Good for you. Don’t plan on your hubby doing it? Keep that in mind.

I agree with everyone else. It sounds like you are the one that is going to have to take on the car maintenance task. Maybe he’ll be shamed when you are the one checking the oil and taking it for an oil change and tire rotation but don’t count on it. Maybe tell him you found a cute mechanic that will help with the work.

Some husbands go out and do much worse in that situation. :imp:

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Maybe but I’m not one of those husbands.

As noted earlier, you were not “bone dry”. The oil level was just below the stick. But I don’t think the oil light was coming on because the pickup went dry from the oil sloshing around. If that was the case, you would have seen the oil light flickering while driving, not while idling.

But unfortunately that means the news is going to be “not so good”. Two things are happening. First, as the oil level drops, the remaining oil is cycled through the engine more times, and the increased cycling rate means the oil has less time to cool down in the pan. That makes the oil hotter and thus its viscosity drops, meaning the oil is thinner. Thinner oil means less oil pressure in the engine.

But in your case, the oil light is coming on at idle partly because the oil is thinner, the oil pump is turning slower and because your engine has a lot of wear.

Now this does not mean that the engine will soon be toast. You could get maybe a few years if you change the oil more frequently, make sure it never goes more than a quart low and maybe switch to 10w30 instead of 5w30. I have gotten an extra 30 to 40k on engines like this, but you can only do that by staying right on top of it. Check the oil daily until you get a feel of its current oil consumption. At least make checking the oil part of filling the gas tank.

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I think you should let your husband know how cute and nice the guy was at the auto parts store, and that you plan to take your car there for an oil check weekly!

In many cars even just the engine pushing air through the system is enough to turn off the light. It comes on at idle because the lower engine speeds mean the oil pump is running slower. If you ask me the pressure warning light should come on way sooner.

You’re lucky the engine still runs at all. It only takes a few miles of driving it that low to kill it.

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I put in a total of three quarts after my post and it was at the middle of the dipstick. The light has not come back on. We had our trusted mechanic take a look and he noticed the oil filter was not fitted properly last oil change. He also suspected the heat (we live in AZ and we had a record smashing 50 days of 110°+ temps) and the distance he drives to work (~25 miles each way) that it just lost that much oil. I will be honest, I told him I only added 2 quarts because he sounded like he was going to pass out just with that info. I didn’t want him to totally lose it. 2 quarts brought it to the low end of the dipstick so I left it at that. But it was three before it was normal. Another mechanic who didn’t work on it did mention he wondered if it was under serviced at the last oil change. Knowing the filter wasn’t installed properly makes that seem plausible to me. I’m still shocked/uncertain that it could get that low and the light wouldn’t stay on but I can attest that it did not.

Thank you all for your input and for not totally dumping on my husband :joy:. I drive a Tesla, thought I was getting away from all this with that purchase, but I guess I will assume the role of fluid checker regardless :woman_shrugging:t2:

Lol he’d be like great I hope you can get a discount that way. He would be totally unaffected :rofl::rofl::rofl: