Can I Just Add Oil To My Car? (Beginners guide)


Modern cars don’t need a ton of love, but do need a little. Checking your engine oil level is one the most important maintenance tasks, and without doubt one of the easiest too.

Can I just add oil to my car? To add oil to your car follow these 4 steps:

  1. Park on level ground
  2. Wait 5 minutes after engine shut down
  3. Remove dipstick to check level
  4. Add oil

In this post you’ll learn how to check your oil level, choose the correct oil type and add your engine oil. You’ll also understand the importance of checking and adjusting the oil level regularly. 5 minutes from now you’ll be a pro!

1 Park On Level Ground

volvo

Park your car on level ground, parking on a steep hill will for example cause an inaccurate reading. Many cars are fitted with a oil volume gauge in the oil pan, the system likely won’t make a reading unless parked on a level surface.

2 Wait After Shut Down

After shutting down the engine wait five minutes, that’s about enough time for the oil to make its way back to the oil pan under the forces of gravity. Measuring before all the oil drains back will cause the reading to show a lower oil level.

3 Check Level

Oil dip stick

Most cars use the traditional dipstick type set up, but more modern higher end vehicles may not have a dip stick installed. Instead they relay on a oil pan oil level sensor.

To dip your car for oil, first locate the dipstick. Most dipstick handles are colored to help with identification. If you can’t find a dipstick under the hood, check your drivers manual for oil checking procedure.

Your car may not have a dipstick. Instead you car will be fitted with an oil monitoring system. Checking the oil simply requires accessing oil check menu through the drivers information panel.

Car oil dipstick

Most of us will have regular dipstick, go ahead and remove it and using some kitchen towel, wipe the stick clean before refitting and removing again to obtain an accurate oil read on the stick.

The stick will have an upper and a lower mark. Words, letters or marks are commonly employed to identify the full and low levels, Full, F, Low, L or just a dash. An oil level in the hatched area between the full and low mark means the level is OK but at the full mark is obviously better. An engine with an oil level below the hatched area needs oil immediately.

Oil level on dip stick

4 Add Oil

Car oil filling

Adding oil isn’t difficult, start by locating and removing the oil filler cap. The cap usually has “Oil” or an oil can symbol and usually also specifies the oil type to use.

When filling oil, spillage is common. To help catch any spilled oil, place a clean cloth around the oil filler. Add a little at a time, and re-dip to check. Adding a complete container at once runs the risk of overfilling.

Engine oil level

Too much oil isn’t good for your engine, it may cause increases crankcase pressure, oil leaks, burning oil and misfiring. Overfilling the oil by a little is OK, but if the dip read comes way up the stick well above the full ark, you’ll need to drain some out.

Is All Engine Oil The Same?

Oil is oil right? No, engine oil is graded by it’s ability to flow at different temperatures. It’s known as viscosity. Oil has a few important functions, the most important of which is to reduce friction between moving metal components. Oil does this by forming a layer between the metal components, so that they glide across the oil as apposed to making physical contact with each other.

Thick oil offers great protection but doesn’t flow around the engine so good. Thin oil flows great, but doesn’t offer a thick enough layer between components.

To add to these problems, oil flows at different rates depending how warm it is. All oil is at it’s thickest on a cold start especially if the weather is Burrr, and conversely at it’s thinnest when the engine is hot and working hard.

The solution to this problem, is blended oil, thin oil mixed with thick. Synthetic man made oil mixed with traditional petroleum based oil. The result is known as a multi grade oil. The thinner oil protects and flows easily during low temperature starts and the heavier oils in the mix help protect when the engine is hot.

The blend differs for different type engines as dictated by the engine manufacturer. Oil types are identified by the numbers you see on the oil can at the gas station.

A common type is 5W-30. The first number and letter “5W” identifies how viscose the oil is at lower temperatures (W for winter). A lower number means the oil is thinner. The second number identifies oil viscosity at higher operating temperatures.

What Oil For My Car?

The oil type for your car is important, however even the wrong oil type is better than a low oil condition. So if you don’t have the correct type, go ahead and top up with an alternative oil type.

The oil type for your car is usually marked on the oil cap or found inside your drivers manual.

Oil is as you know graded by it’s viscosity and the number will look something like 5W-30 or 10W-40 etc.

Oil choice is dictated by 3 basic factors

  1. The engine performance
  2. How old your car is
  3. The ambient temperature

Can I Add Oil To My Car When It’s Hot?

Yes you can add oil to your engine when it’s hot, but obviously the engine needs to be turned off and aloud five minutes for the oil to settle before using the dipstick.

Is It OK To Add New Oil To Old Oil?

Yes you can add new oil to old oil. However adding new oil isn’t a substitute for changing the engine oil. Old oil will contain acids and metal filings, only draining the oil pan and filter will renew the oil system.

Oil and filter is typically changed every 10 thousand miles.

Car maintenance chart

Why Do I Have To Add Oil To My Car Every Week?

Constantly adding oil to your car is a pain in the ass and it’s expensive. There are two likely reasons you have to add oil to your car every week.

  1. Burning oil
  2. Leaks oil

1 Burning Oil

Blowing blue/white smoke out the tail pipe is a sure sign your car is burning oil. A smell of burning oil, smoke when you hit the gas pedal and constant tops is as you know a sign all is not well. Here’s a list of common causes of burning oil starting with the simplest solutions first.

  • Overfilled oil level
  • Faulty PCV
  • Faulty turbo oil seal
  • Worn valve stem seals
  • Faulty head gasket
  • Worn piston rings

A blocked PCV valve is a common problem and will cause the engine to burn oil. Replacing the valve is an easy repair to make and they’re cheap too at about $20.

If your engine only smokes in the morning on start up and when you punch the gas, it’s likely your oil stem valve seals have become hard. This is common on cars at about 10 years old. It will require a trip to the shop, but as repairs go it’s not that big a deal.

A faulty turbo oil seal is a common cause of oil consumption and will require some detective work to diagnose.

Engine wear is obviously common in older cars and a compression test will confirm a weak cylinder(s).

Compression test infographic

2 Leaking Oil

Engine

Old engines leak oil, that’s what they do. Sealer and gaskets break down after years of good service and a leak usually starts with a sweat and develops into a flow. Leaks don’t get better by them selves they get worse.

Leaks are very often ignored by owners, after all the car is old and a quart of oil is cheaper the the labor to fix the problem. Here’s a list of common areas for oil leaks, I’ll list the easy to fix one’s first.

  • Loose oil filter
  • Oil drain washer worn out
  • Oil cap seal worn
  • Turbo banjo bolt
  • Cam/rocker cover
  • Oil filter housing
  • Front cover
  • Oil pan gasket
  • Oil cooler leaking into coolant system
  • Head gasket

When oil leaks from an engine the airflow will cause the oil to cover the whole underside of the vehicle and so can be difficult to identify the origin. To successfully identify the source of the leak, begin by washing the engine and underside being careful to avoid the electrics. Continue to drive the vehicle but examine regularly to identify the leak(s).

Many leaks are minor and easily repaired, others may be a ton more complex and uneconomic. Consider trying an engine oil stop leak product, it may not stop the leak completely but if it slows the leak, it will pay for itself.

Why Is There Oil Way Up The Dipstick?

Oil all the way up the dipstick is normal when removing it initially after and engine shutdown. However if the oil level is reading way up the stick, it suggests your engine crankcase is over full. It may not be oil though.

I often need to remove excessive oil from engines after the customers overfill them accidentally and it’s an easy mistake to make. If you think that’s the problem go ahead and remove the oil, by draining it out using a siphon.

If however you didn’t overfill the oil, the next most likely cause of the high dipstick reading is a coolant to oil leak. A couple of ways this can happen is through a faulty oil cooler or a failed head-gasket.

Check the coolant level, if it’s low or you’ve needed to top it up regularly it’s likely you found the problem. Oil coolers are plumbed to the coolant system and used to help control oil temperature.

If the internal element ruptures coolant and oil will mix. replacing the cooler will fix the problem, however the coolant system and engine will need to be flushed.

Head gasket failure chart

A faulty head-gasket is the other likely cause, the gasket keeps the oil and coolant ports separate and any damage between these ports will allow the fluids mix. To test for this condition, use a coolant system pressure tester and expect to hear pressure escape the crankcase via the dipstick.

Replacing the gasket is a job for a mechanic. Likewise the engine and coolant systems will need to be flushed.

Can I Put 5w30 Oil In My Car?

5W-30 is a pretty common grade oil and it won’t hurt your engine any to use it. However, it is best to use the manufacturers recommended oil type and grade. Your engine maker has likely made their recommendations based on hours of scientific testing.

You’ll find your cars recommended oil type and grade either on the oil cap or in the drivers manual.

Can You Feel The Difference After An Oil Change?

Most owners likely won’t notice much difference after an oil change. However, if your car has a ton of mileage the engine is likely to sound and run a little smoother with an oil change. But be assured, if it sounds different or not your car will run a ton better with fresh oil.

Related Question

Can too much oil cause Hydro-lock? Too much oil in an engine crankcase can cause the engine to stall a condition known as hydro-locking. Overfilling may also cause engine oil seals to fail and leak oil.

John Cunningham

John Cunningham is an Automotive Technician and writer on Rustyautos.com. I've been a mechanic for over twenty years, I use my knowledge and experience to write articles that help fellow gear-heads with all aspects of classic car ownership, from tires to roof aerials and everything in between.

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