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5 Signs It's Time to Change Your Oil

Wrench Wench has been in love with automotive mechanics for decades. She loves sharing advice with fellow DIY mechs and curious cats.

An engine in need of an oil change is a potential hazard; learn the signs it's time to change your oil and avoid more costly repairs.

An engine in need of an oil change is a potential hazard; learn the signs it's time to change your oil and avoid more costly repairs.

How Do I Know When to Change My Oil?

Here are five signs that your engine that needs an oil change as soon as possible.

1. You've Passed the "Safe Zone" of 3,000 Miles or 3 Months

The simplest way to know if it's time to change your oil is to ask yourself:

  • Have you driven your car, truck or van farther than 3,000 miles since your last oil change?
  • Or has it been more than 3 months since its last oil change?

If so, change your oil. If you do, you may not have to think for years about any other signs that you need an oil change.

The 3/3 rule—3000 miles or 3 months—is by far the safest and most effective way of ensuring a long life for your vehicle, with minimal internal repairs needed throughout its lifetime. This interval is what just about every owner's manual and ethical mechanic recommends.

2. You Hear an Ominous Ticking Sound on Start-Up

It's a normal day like any other, and you've got no reason to suspect any transportation challenges.

But when you go out to start your car or van, the starter kicks the engine on, and you immediately notice an ominous ticking sound coming from the engine compartment.

If you open the hood for a closer look, you'll notice that rhythmic ticking seems to be coming from the top side of the engine, nearest to the valve covers.

If that tick seems to fade away after your vehicle has warmed up, you're likely just a little bit low on oil at the moment, which usually only occurs when your oil has passed its prime and needs to be changed now.

If that tick seems to stick around for 30 minutes or more, or it's accompanied by low engine power or turns into a louder knocking sound, you're about to manifest some avoidable vehicle troubles.

That ticking sound is a bad omen, and is the manifest symptom of an engine that is almost completely void of oil, its life blood!

Fortunately, low or no oil is easily remedied by adding some oil ASAP.

There are no reasons that a fully functional and properly sealed engine should ever lose all its oil. When it does, that's a sign that you need to change your oil and take your car in to be checked for oil leaks or bad piston rings.

3. Your Oil Has Become Thick, Dark and Smelly

Fresh, clean, and viable engine oil is a golden brown color and is mostly transparent.

It should only have a hint of oil-ish smell to it, and shouldn't have any debris, dirt or lumps in it.

If you notice when you check your oil dipstick that your fluid is no longer transparent, that's the best time to change your oil in order to keep your engine looking as good on the inside as it does on the outside. Changing your oil before it loses its full transparency will extend the life of your engine's internal parts too, which cuts the costs of the most common and unnecessary repairs from low-mileage vehicles that consistently had oil changed a little bit late.

By the time you notice the oil has lost all of its transparency, when it starts to turn super dark brown or jet black or becomes super thick and pungent, you're already way beyond the "change it now" moment. You're way beyond 3,000 miles, and most likely outside of the safe zone under your warranty (your warranty could be voided for neglect).

4. Your Car Is Having Problems Starting

Depending on the year and model of your vehicle, you might experience starting problems or no-starts when you're super low or out of oil.

I've experienced this mostly on vehicles newer than 1981.

It's curious that some cars will start even if they are just about out of oil. I experienced this on a 1993 Jeep Wrangler that I dearly miss, a car given to me by an aunt who has no mind for mechanics or basic vehicle maintenance. At the time I didn't realize she had never done any regular basic maintenance on the Wrangler—not even checking the oil—so I didn't think there was any reason to check fluids before getting on the road.

Without any complaints or reports of it running funny or needing anything, I just assumed it was good to drive 40 miles south to my husband's shop, where I could give it a once or twice over.

To my complete shock, when I began checking things out, the first thing I found was that it was BONE DRY on oil AND coolant.

And when I say bone dry, I mean it. When I went to change the oil and drain any remaining old coolant, nothing came out of either compartment.

That car never gave any indication to my aunt, nor to me on the day that I received it, that anything was wrong at all. And furthermore, that jeep never even stuttered until a few years later when the heater core went out.

On the other hand, I had a 2002 Pontiac GT that let me know pretty quick that something was wrong. It turned out to have a defective oil cap gasket from the factory, which caused it to lose oil quickly when the gasket finally failed, and that was when I first noticed it was having a tough time with starting. It took less than 24 hours before it didn't want to start at all.

I pulled out my probes and ammeter and noticed everything was fine with the starting electrical system. Then I checked the oil and noticed it had only the tiniest speck of oil in it.

At that point, I wasn't aware low oil could cause starting problems on its own. Though as I soon confirmed, in many vehicles born in the new millennium, oil sensors are ability to communicate car or truck's brain, cutting further internal damage off at the pass by suppressing the ignition/starting system.

5. Oil That Disappears

There are many things that can cause an engine to lose or burn through its most vital fluid, oil.

When you start noticing your car or truck is losing oil more often, the culprit is most likely to be an oil leak around one of the gaskets meant to keep it inside the engine.

Secondarily, if your engine is super high mileage (say 250,000 to 300,000 miles), your piston rings could have finally worn down enough that they're now allowing small amounts of oil to pass into the combustion chamber; which then gets burnt up and spit out as blue or black smoke. A similar process can happen with old lifters.

Regardless of whether your oil is disappearing because of a leak or because it's being burned up, it's essential that you get your oil changed ASAP. And if oil is disappearing, you should follow up that oil change with a UV oil leak test and have a mechanic determine whether it's worth your while to open up the block and examine the pistons and rings.

For those of you in a hurry, I've thrown together a handy table below, listing the most common signs that indicate it's time to change your oil now.

Signs It's Time to Change Your Oil Now

No or low oil on the dipstickTicking or knocking sounds

Thick or smelly oil

Pungent-smelling oil

Grainy or lumpy oil

Oil is dark brown or black

Oil is a mocha brown or yellowish-brown color

It's been over 3,000 miles or over 3 months since your last oil change

Oil is "disappearing"

Your Check Engine Light has come on or been on for a while

Lower MPGs

Your vehicle has been sitting for several months or years

This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.

© 2018 Wrench Wench