CarTalk.com Blogs Car Info Our Show Deals Mechanics Files Vehicle Donation

Started car without oil

Sigh I messed up badly.

I’ve always done my own oil changes and have not encountered issues but today… I started changing my oil, drained the pan, tightened the bolt and left for about 15 minutes. I came back and went to reset the oil light, forgetting to put oil back in. I turned on the car but realized my mistake as soon as it fired up, only ran for 5 seconds, 8 tops. I turned it off, filled it up, and then drove it. I’m not hearing any unusual noises but I’m pretty gutted about making a mistake like this. I only changed the oil, not the filter, so there should be about 1 liter of oil still in the car. Where I live, the temperatures drop to below -15 degrees Celsius regularly so my guess is cold starting on a morning still results in a few moments where the car runs without oil… So maybe my mess up was equivalent to 15 cold starts… i honestly don’t know but I’m panicking about the damage I did to the car. It is a 2007 Accord Se with the 2.4L I4 5speed manual. I’ve run synthetic oil in it and i’ve read that it leaves behind a thin film so there might still have been some lubrication. Any help or insight is appreciated. Thanks!

If it were mine, I’d fill it back up with oil, start the engine, and drive on.

I don’t see what else you can do at this point. If the engine is toast, it’ll be apparent pretty quickly, I’d guess.

Good luck.

2 Likes

In case anyone is wondering how long an engine can last without oil

1 Like

Five seconds is not enough to cause harm since there is usually enough residual oil left on the cylinder walls to prevent damage. I once nearly ran a car out of oil at highway speed due to the oil filter blowing loose after a badly done oil change by a major oil service station. There was one quart left and after towing the car to a nearby station, the oil was changed properly and I was on my way.

1 Like

To the OP – I made the same mistake once. There was no damage to the engine. Just keep driving but also keep listening for any slight rod bearing knock. I bet your engine is OK.

1 Like

I agree with the others saying that you probably didn’t run the engine long enough to cause any meaningful damage.

1 Like

If the engine was run before you began the oil change, there’ll likely be enough oil on the cylinder walls and entrapped in the galleys, between the sleeve bearings, etc. to protect the engine for 5 seconds.

In any event, I certainly wouldn’t fret about it. The past, even the very recent past, is gone. Fill it with oil, listen carefully for any new unusual sounds, and… hearing none… drive on and enjoy your ride.

1 Like

neighbor had same issue with his new lincoln navigator. they moved it out of bay to parking lot and only than found out it had no oil. dealer extended warranty to 100k miles or so. he sold it to brother with @150k miles and it is at 300k now. seems to me the nav had the 4 cam 5.4 motor?

1 Like

I agree with others here. I have seen several automobiles started and driven from a few hundred feet to 4 blocks with no oil and suffered no damage. .

1 Like

Thanks everyone! This really helped put me at ease. I have been driving it for two days now and don’t hear anything suspicious. As far as I understand, a rod knock is pretty noticeable. Before the incident, I drove the car and it was turned off 20 minutes before I started it again. I’ve checked the oil level a few times afterwards and am not seeing any change, the colour is also still good. Once again, thanks for the support, I won’t have to lose sleep over this anymore.

3 Likes

Yep, drive on be happy. You have to remember that when your car sits overnight, all of the oil drains back in the pan. What’s left is a film of oil on the critical parts until the oil from the pan starts pumping again. So really not much different than a normal morning start. I won’t bother telling about forgetting to put oil in the lawn mower and running it for a few minutes.

As we age, I have tended to use obvious reminders and particular sequencing of steps just so I don’t forget something. So the hood is up, the oil fill cap is off, the funnel is in the oil fill, and the oil bottles are on the radiator support under the hood. That way it is virtually impossible for even me to forget to put oil in. Even if I died in the process, the wife would know to put the oil in before starting the car and driving to the funeral home. Come on, tell me you guys haven’t thought about that?

2 Likes

Bing made an excellent point about morning starts.
You, my friend, need not worry.
Happy motoring.

Even though there wasn’t any oil pressure, all your engine parts were still oily enough to be well lubricated for the 5 to 10 seconds you ran he engine.
Bearing journals do not drain empty when the engine sits, surface tension, or capillary effect keeps oil in the clearance space of the bearing, even in engines that have sat for months, and that oil film will float the bearing journal before the electric starter even makes a complete turn during the start.
Also, there is very little load on the bearings of an idling gasoline engine, The pistons are compressing a vacuum when the throttle is closed.

1 Like

Would it make sense for a sensor to prevent starting a car if the oil level is too low? I can’t start my manual transmission pickup without the clutch unengaged even if it’s in neutral. There are rare times I want a foot on both the gas and the brake to start, have learned to use one foot on both, but it’s clumsy.

Hope. Not in my opinion.

Simple , transmission in neutral - parking brake set - left foot on brake pedal - right foot on accelerator - not clumsy at all .

My Buicks all had a secondary switch on the oil pressure sensor to shut the fuel pump off if there is a loss in oil pressure. We’ve discussed this before. Some cars have it and some don’t. At any rate wouldn’t do much on initial start up since oil pressure is just building. Remember when changing oil prior to some of us who would fill the filter too, the oil light would be on for a few seconds until pressure came up again. I think at any rate it’s more important to have the engine shut down if oil is lost while running. Unless of course someone else does your oil changes so then its a good idea to check the oil to make sure they filled it.

One still needs the clutch disengaged (=clutch pedal pressed to the floor): there’s a switch. I think you can do this with an automatic - they lack clutches.

My manual transmission car starts just fine without having my foot on the accelerator. Any car with a carburetor where the driver sometimes needed to pump the gas pedal to get an engine to start was likely built before they had starter interlocks tied to the clutch pedal.

I’m not sure when starter interlocks were introduced, but all carbureted engines had to be pumped to start when cold (not at operating temperature). It was necessary to (1) set the high idle and (2) inject via the accelerator pump a spray of fuel to prime the system.