Symptoms of Having the Wrong Engine Oil in Your Car (What Happens?)

Oil is your engine’s lifeblood, minimizing friction and heat. But it breaks down with use, so you must change it regularly with the manufacturer’s recommended type.

However, mistakes happen. What if you accidentally put in the wrong oil? We’ll cover what using the incorrect oil does to your engine, how to fix the issue, and how to avoid it in the future.

wrong engine oil in car

See Also: What Happens When You Drive Without an Oil Cap?

Engine Oil Service Classifications

In the United States, the American Petroleum Institute (API) sets standards for measuring the characteristics of passenger car engine oil. Over time, the oil required by vehicles has changed.

Cars from the 1920s, 1950s, 1970s, and so on require a different formulation of motor oil. Therefore, different engine oil classifications exist and will likely continue to be created in the future.

Gasoline Engines

The current service classification for today’s gasoline powered cars is “SN PLUS” which was introduced in 2018.

For new cars (2019 and newer – depending on when you read this), you want to make sure the motor oil you purchase has this classification noted in the “API Donut” image (see examples below) which is visible on all bottles of motor oil.

API donut

For older cars (2018 and older), you can also use motor oil with the “SN PLUS” classification but you may be able to also use older classifications depending on when your car was built. The table below notes these classifications.

CategoryModel YearsStatus
SN PLUSUse in gasoline engines of today's cars and older.Current
SNUse in gasoline engines for cars built in 2018 and older.Current
SMUse in gasoline engines for cars built in 2011 and older.Current
SLUse in gasoline engines for cars built in 2004 and older.Current
SJUse in gasoline engines for cars built in 2001 and older.Current
SHDon't use in cars built after 1996.Obsolete
SGDon't use in cars built after 1993.Obsolete
SFDon't use in cars built after 1988.Obsolete
SEDon't use in cars built after 1979.Obsolete
SDDon't use in cars built after 1971.Obsolete
SCDon't use in cars built after 1967.Obsolete
SBDon't use in cars built after 1951.Obsolete
SADon't use in cars built after 1930.Obsolete

Because of this, all the oil you buy in the present will have to be equal or better than the previous standards such as SG, SF, SJ, SL, and SM. Check your owner’s manual to find the right oil for your car and at least 2 accurate multi-grade specifications that coincide with the engine of your vehicle.

Do not just look for a brand name when choosing oil. Your manual should recommend an oil that has a requirement such as “compliant with standard SN of API.”

Diesel Engines

Vehicles powered by diesel engines have their own motor oil classifications. The types are a lot more confusing but the American Petroleum Institute does a good job explaining here. As long as you follow what your car or truck manual says, you’ll be fine.

Oil Viscosity

best motor oil for high mileage cars

The motor oil in car engines has to function under various temperatures and pressures. For example, vehicles must endure cold weather during winter and hot weather during summer.

Oil has a harder time flowing in the cold and an easier time flowing in the summer. And if you’re towing a heavy load on top of that, it is even more work for the oil. This resistance to flow calculation is known as viscosity.

The numerical codes of these standards are defined by the Society of Automotive Engineers (SAE). Examples of engine oil viscosity include: 5W-20, 10W-30, and 20W-50.

See Also: What Happens If Antifreeze Gets In Your Oil

Low Temperatures

The first number followed by the letter “W” in oil viscosity indicates how thick the oil is at low temperatures. The “W” stands for winter. The lower the number, the thinner the oil.

Since thinner oil flows better than thicker oil at low temperatures, running a 5W-20 oil would be much better in a Michigan winter than something like a 20W-50.

Related: Can Motor Oil Freeze?

High Temperatures

The second number in oil viscosity indicates how thick the oil is at normal operating temperature. The higher the number, the thicker the oil.

Thicker oil protects engine parts better than thinner oil under tough conditions. For instance, if you’re driving in Arizona in the middle of summer, a 20W-50 motor oil would protect your engine better than a 5w-20 viscosity.

Of course, you should always follow the manufacturer’s recommendation of what oil viscosity weight you should use in your vehicle. Too thin of an oil can result in not enough protection. Too thick of an oil can clog passageways (as is the case of DTC P0014).

Now that you should have a decent understanding about the basics of engine oil, here are some symptoms you may see if you accidentally put the wrong oil in your car.

See Also: Should You Check Oil When the Engine is Hot or Cold?

Wrong Oil in Car Symptoms

#1 – Hard to Start in Cold Weather

If the cold viscosity of your oil is too high (the oil is too thick), then you may not be able to start your car in very cold temperatures. In this case, the oil is too thick to properly lubricate all moving parts and this causes excess resistance during car starts.

#2 – Oil Leaks

engine leaking oil

If you use a synthetic oil on an older or high mileage car, you may start to develop small oil leaks you would not get had you used a conventional motor oil.

This is simply due to the different flow characteristics that synthetic oils have which conventional oils don’t. It allows the oil to squeeze through tighter areas than regular oil.

Synthetics also typically have additional detergents that will often clean out gunk that may have been plugging a small oil leak. In this case, the extra cleaning ability may cause an existing leak that was temporarily plugged to be uncovered.

While using a synthetic oil in these cases won’t necessarily cause any damage, you may notice drops of oil on your garage floor or a burning smell while driving. Because this oil is slowly leaking, you want to pay extra attention to your oil level and top off when needed.

Switching back to a conventional oil on your next oil change is recommended. Some vehicles simply don’t do well with synthetic oils.

See Also: Can Oil Go Bad If You Don’t Drive Enough?

#3 – Smell of Burning Oil

burning oil smell

If the hot viscosity of the motor oil is not high enough, the oil may start to break down under extreme (hot) conditions and it won’t lubricate the components of the engine properly.

This will result in the oil being burnt. Over time, this can lead to long-term damage in your engine due to excess friction between metal components.

You may also experience the burning oil smell due to using synthetic oil and it leaking as mentioned above.

#4 – Poor Fuel Economy

bad fuel economy

If you use too thick of a motor oil for the conditions, your fuel mileage will likely suffer. This is because the thicker oil increases resistance on moving parts such as pistons. While your engine will be protected, it will be at the expense of more frequent trips to the gas station.

Switching to a slightly thinner oil (example: 20w-50 to 10w-30) should help the situation.

#5 – Engine Ticking in Cold Weather

causes of engine ticking noise while idling or accelerating

If you use too thin of a motor oil for the conditions, you may hear your engine making a ticking noise. This will usually be the loudest right after starting up and gradually decreasing after driving around for a bit.

This happens because the wrong weight of engine oil can do a poor job of coating and lubricating all engine components. What you are hearing is metal components such as valves and valve lifters hitting against other metal. Temporarily switching to a different oil viscosity may cure the problem.

Mixing Synthetic Oil with Conventional Motor Oil

conventional vs synthetic blend vs full synthetic oil

If you accidentally add conventional motor oil to synthetic motor oil (or vice versa) to your engine, you have nothing to worry about.

The only reason why you wouldn’t want to do this is that synthetic motor oil is expensive and by mixing the two types, you’re simply not getting the benefits of the synthetic properties since the conventional oil is compromising those benefits.

At the next oil change, simply choose one type of oil over the other. Do not mix them.

Mixing Different Oil Weights

Should you worry if you accidentally add a thicker oil (ie: 20w-50) to a thinner oil (ie: 10w-30) that’s already in the engine? In most cases you’ll be fine.

Mixing the oil viscosities simply blends the two weights together. You simply don’t want to stray too far away from what oil viscosity the car manufacturer recommends to use. Using too thick of an oil can result in high oil pressure in some cases.

Mixing Different Oil Brands

conventional motor oil

While it’s not recommended to mix various brands (example: Valvoline, Castrol, Mobil 1, Amsoil, etc.) of oil, it won’t cause damage to your engine. What matters more is sticking with the same oil viscosity.

Since different motor oil brands have slightly different additives, you may be negating the benefits of one additive because you’re diluting it with a brand that doesn’t have that additive. It’s not a big deal but when you need your next oil change, stick to a single oil brand.

How Temperatures Affect Engine Oil

What Happens in Hot Weather

dog in a hot car

During hot weather, the engine of your car naturally tends to heat up faster, which in turn can affect the performance of the motor oil.

If the oil viscosity is too low, it might cause the oil to burn because it’s too thin for the hot environment around it. This can lead to increased friction within the engine and eventually wear down its components. To avoid this issue, it’s often necessary to use thicker engine oil in hotter climates.

Another aspect you need to consider is the reduced mileage. Using the wrong motor oil viscosity, especially if thicker than recommended, will directly affect your car’s mileage. The critical moving parts, like pistons, have to work harder to move with the additional resistance that thicker oil gives.

What Happens in Cold Weather

starting car in cold weather

In cold weather, oil has a harder time flowing, making it important to use thinner engine oil. Using oil with a higher viscosity than recommended can result in increased resistance inside the engine, leading to difficulties when starting the car.

On top of that, the poor flow of oil might not provide adequate lubrication for the engine’s components, resulting in higher friction and wear.

Keep in mind that temperatures also play a significant role in the illumination of the oil light or check engine light. These lights are connected to sensors that monitor the oil pressure and engine temperature, and if either of these measures is out of the normal range due to the wrong oil type, the lights might turn on.

How Using the Wrong Oil Impacts Engine Components

Oil Filter

When you use the wrong type of engine oil, it can affect your oil filter’s ability to catch debris and contaminants. Since the engine oil is not the correct viscosity, your filter might become clogged, leading to a decrease in oil flow and potentially damaging your engine components.

Oil Pump

Your oil pump is responsible for circulating oil throughout your engine. If you have the wrong engine oil, it can put extra strain on your oil pump. This is because the pump has to work harder to move the oil through the engine, which could result in premature wear.

Oil Pan

The oil pan is the reservoir that holds your engine oil. When you use the incorrect oil, it can cause issues with the oil pan, such as increased sludge buildup and worn seals. This may result in oil leaks and decreased engine performance.

PCV Valve

The positive crankcase ventilation (PCV) valve helps maintain proper pressure within your engine’s crankcase. Not using the correct engine oil can create an imbalance in the PCV system, allowing contaminants and debris to build up. This can affect the overall performance of your engine, as well as increase emissions.

Piston Rings

Piston rings play a vital role in sealing the combustion chamber and ensuring proper lubrication within the engine. When the wrong oil is used, it can lead to decreased lubrication, causing excessive wear on the piston rings.

Additionally, inappropriate additives in the oil may further degrade the piston rings, resulting in a loss of compression and decreased engine efficiency.

To Avoid Any Issues

If you’re still confused as to what oil type, viscosity, or weight you should be using, consult your owner’s manual. Your car manufacturer is by far the best resource for determining the best motor oil for your vehicle. 

If you live in extremely hot or cold climates, you may need to use a slightly thicker or thinner oil but for the majority of owners, stick to what’s recommended.

Mark Stevens


  1. We just left a rest area and we’re cruising down the interstate when a warning came up that the hybrid system had a problem and power was reduced. Next a warning appeared about low oil pressure. We stopped and I checked the oil level which was good. We than had the 2021 Highlander towed to the nearest Toyota dealer. They did the diagnostics and first on the list was to change the oil, which they did. After the change, the oil pressure check showed it above specs and not low. We’ve only had the vehicle for a couple of months (approximately 4000 miles) and it has performed well except for the gas mileage which is no where close to Toyota’s sales pitch. The oil had been changed shortly before we bought the vehicle (used) but I don’t know what viscosity they used. The vehicle is supposed to use 0W-16. It seems strange to me that after driving the vehicle that many miles and on a couple of long road trips that this even occurred without something else being wrong. We’ll see what happens when we get the vehicle back and resume our trip

    1. The vehicle should still be under warranty if it’s that new. Did the dealership say anything about how they plan to address the problem?

  2. My car is going in for service in 7 days, but needs oil. It is stalling at low revs when turning corners.It is Citroën C3 2017 recommended oil 0W-30. I have some 5W-30 left over from a previous vehicle. Could I use this for a week? An oil change will be done with the service. I am in Wales. Temp not under 0 Celsius forecast.

    1. Yes you could use 5W-30 for a week. It’s just a little thicker when you first start the car before it’s warmed up. I’m not sure the stalling is caused by low oil, though.

    1. No worries. My thoughts on the matter are the same whether they put 5W-30 or 10W-30 in the car, because the oil acts as a 30 weight in either case at operating temperature.

  3. Just back from a 4000 km trip. Halfway through I was due for a oil change. Took our 2015 Hyundai Santa Fe into a local shop in Florida. Seems they refilled the car with 10W 30 rather than the 5W 20 that is recommended and has always been used. Towards the end of the trip the oil light was flickering some yet the car seemed to be running well. Wondering if the incorrect oil would cause the oil light to come on?
    Perhaps changing the oil again with 5W 20 would address this?

    1. Generally the red oil light illuminates when you have low oil pressure. I think it’s unlikely that running 10W-30 instead of 5W-20 would cause a low oil pressure light, so there might be some other underlying cause.

      You can try changing back to 5W-20 but I don’t think that will resolve the issue by itself.

  4. I use a Toyota Camry 2008, I had the oil seal between the engine and gearbox change and had my engine oil changed from Total 20W-50 to HPS 20W-50, my car would start and not accelerate at full capacity when on motion. I have changed the fuel pump, plugs, coil yet no improvement. Took the car for scan and P0166 code was detected. i.e Crankshaft Position Camshaft Position Correlation Bank 1 Sensor ‘A’. All the sensor was checked and working properly. The timming chain was checked and it’s ok. 271230 mileage. Excess fuel consumption and heavy tapping sound when you turn on the engine that stop after awhile
    Yet the acceleration on motion is too slow. Is it the change of oil that is causing it?

    1. I think it’s very unlikely that an oil change caused that issue. Are you sure that’s the right code? I think P0166 is for an O2 sensor.

  5. What would happen if Castrol 5W-30 A5 was put into my Mercedes GLE 350D by mistake instead of Castrol 5W-30 C3.

    The reason is my engine has seized after service July and after 4000miles

    1. You would have to double check the owner’s manual to confirm this, but I think A5 would still have all the necessary certifications for your vehicle. I really don’t think this oil would cause your engine to seize.

      1. The oil put into my car was Castrol 5w-30 A5 oil

        I contacted castrol they told me this oil is not allowed for my car.

        The Car manual states on use oil that use MB229.31 MB229.51 MB229.52

        1. Good you checked with Castrol, however I would still be surprised if this oil caused your engine to seize. Please let me know what you find out if you could.

  6. I’m in Nigeria, Africa and I recently changed my car (Lexus RX350, 2007) engine oil with 6 Litres of Mobil 1 5W30 fully synthetic. Two days after the oil change, I noticed my check engine light was flashing. The car was taken to an auto-workshop immediately where the oil check was found to be extremely low, water was seen gushing out from the exhaust pipe and the car was difficult to start. The auto engineer concluded that the top cylinder gasket was burnt and some of the valves were bad after further check.
    The mileage on the car was 180,420; no evidence of oil leakage and the vehicle was not smoky prior to the incident. The top cylinder gasket and all the 24 valves were replaced.
    Oando oleum SL 20W50 was suggested for a further oil change by the auto repairer.
    Is the suggestion a wise one or not?

    1. I personally do not use oil that heavy in any of my vehicles, and would not recommend it on a vehicle that has 5W30 specified from the factory.

  7. Great article to read! Now I learned next time I will check and remember all possible symptoms in case there will be a problem with my car.

  8. Bought a 2009 Audi A3 1.9 tdi 173000 miles
    Was low on oil when bought so topped up with a regular 5/30 full synthetic now getting loads off white ish smoke but does clear when on motorway but when been sat about smokes really badly should I get service or any ideas thsnks

    1. I’d do a compression and leak down test so you can get a better idea of what’s going on with the car. When you buy a used car, you often don’t know what you’re getting into until the car is inspected closely.

  9. white smoke = bad head gasket or cracked head gasket allowing water into the cylinders.
    Blue / black smoke = oil in cylinders
    Blue also could be lean fuel or bad spark not burning fuel
    Black smoke is burning oil.
    White smoke is steaming water vaper

  10. I’m in Nigeria, Africa. I use 20W-50 for my car but the recommended one is 5W-30 engine oil. My exhaust emit white smoke. What’s wrong please ?

    1. It’s generally recommended to stick with the manufacturer’s recommended oil viscosity, unless you have a very good reason for switching (such as extreme temperatures or operating conditions). There is a big difference between 20W-50 and 5W-30. It’s hard to say what the root cause of the white smoke is without a bit of testing.

  11. My Optima hybrid is hesitating at highway speeds and is challenged with losing some power on upgrades when the hesitation randomly occurs. After the hesitation, the oil light comes on very briefly then goes off and the engine runs normal again. Oil is full and fairly recently changed. Wrong oil?

    1. The oil light usually means you have low oil pressure. I would have the oil pump tested to make sure it isn’t on its way out.

  12. I have a 2006 Explorer 4.0 and took my car to the dealer for an oil change. When I got it back, the engine was ticking, and they said the timing chain is bad and I need a new engine! After review of my paperwork, I see that they overfilled the crankshaft by 3 quarts and used the wrong oil. 5W20 instead of 5W30. It appears they thought my truck was a V8 with the 4.6 engine. Did using the wrong oil, and too much of it cause my timing chain to stretch causing damage? Of course they won’t take responsibility.

    1. That amount of difference 5W20 -> 5W30 will not make a huge difference. Take into consideration many cars allow you to run different weights depending on your climate conditions and/or oil availability. As an example my 2006 VW Jetta can take either 0W40 (colder climates) or 5W30 (warmer) engine oils. You might just get worse gas mileage.

      Also, the difference between the 4.0 -> 4.6 ford is 1 quart NOT 3 (not to mention you don’t fill up your crankshaft with oil but instead your oil pan but I know what you meant hehe). Running a quart too much isn’t going to cause immediate catastrophic damage, you’d likely see blue smoke since you’d be feeding excess oil past your pistons and your PCV system. I’d also bet you’d noticeably see oil coming out of the dipstick tube and all over your engine which would have been quite difficult to clean up.

      Given that the car is 14 years old it’s it was probably well overdue for a timing chain (or likely tensioner) service.

  13. Hi! I changed my oil 01/10/20 and added Mobil1 “Annual protection” OW-20 in my 2010 nissan rogue, its been a couple of days now but nothing negative as yet, will this cause any damage? Thanks

    1. Nissan recommends a 5W-30 for your Rogue but you should be fine even though the oil you put in is a bit thinner.

  14. Some cars tend to smoke if overfill the oil;but probably yours it might be the rings or that table charger’s seals are gone

  15. I smelled something burning in my car. I pulled into a gas station and checked my oil. I added 2 quarts of oil that my car stayed. Went to pull off and my car was hesitating and then a big cloud of white smoke. I don’t understand. It it was running fine before I put the oil and I put the oil in the car started.

  16. I took a land rover defender diesel engine old model to a filling station and they put synthetic oil. After a distance. It smoked heavily from the exhaust. There were some oil leaks. The vehicle seemed to accelerate itself. Even when I switched it off, the engine was still running. There was heavy black smoke everywhere like the vehicle was almost burning. All the oil was completely finished that’s when it stopped.
    When I put the right oil. It still stated but smoking heavly and no power to pull. Could my new turbo be destroyed?

  17. I took my car to CarX and they put regular oil in my car. I know because of the price they gave me. I told them it was wrong because my car takes synthetic. They said they drained it but now my car smells like burning oil and it’s a mess under my hood. My remote start won’t work as my engine light is on now and my car sputters when I’m at a stop. Should I change my oil personally? I’m afraid maybe they didn’t actually drain it and put the synthetic as they told me.

    1. Unless your car’s manual specifically states you MUST use synthetic oil, conventional oil is usually fine even if you were running synthetic previously. Usually only some high performance or turbocharged vehicles actually require synthetic since they operate at a higher temperature and synthetics take longer to break down.

      All those symptoms sound like something else as a normal oil change wouldn’t cause that. Did the oil cap possible not get tightened on or did they put in too much oil? Both of these might cause excess oil in the engine bay which would burn and possibly cover some sensors.

      Check your oil level and use a diagnostic scanner to see what triggered the check engine light.

      1. Hi
        Our car seems to be overheating and stalls
        We wait 15 mind for it to cool down before we can start it again. It actually goes dead

  18. That’s a computer issue (sensor) not an oil/mechanical issue. I replaced mine last year also and have to replace the power control module today.

  19. 2000 Mitsubishi minter sport my camshaft position sensor failed now it seems like my engine seized it’s locked up.

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