What Happens When You Accidentally Put 5w20 Instead Of 5w30?

5w20 vs. 5w30

There are affiliate links on this article. If you make a purchase through any of the links, I may earn a small commission at no extra cost to you.

So you accidentally put 5w20 instead of 5w30, and now you’re bothered if that mistake would cause damage to your car engine? But what happens when you accidentally put 5w20 instead of 5w30 oil?

Actually, there’s nothing to worry about here; some drivers even mix synthetic oils with conventional ones and their engines still run fine.

The truth is, mixing motor oils does not directly affect the engine, but yes, it does affect certain components in the engine bay.

So, because you mistakenly poured 5w20 into your engine that uses 5w30 doesn’t mean you’d deal with a fatal engine breakdown while driving.

That said, what are the scenarios that could occur from using the wrong oil on your engine? Let’s discuss.

5w20 vs. 5w30: The Differences and Similarities

Firstly, these two oils would flow at the same rate in cold temperatures because they have low viscosity at low temps. This is represented by the number “5” that appears before the letter “W” in both oil containers.

However, in contrast, these oils do not have the same weight; so, they do not offer the same level of protection to seals and other volatile components in the engine bay that requires constant lubrication.

The main difference between these oils is how they’d flow in high temperatures. Yes, they’d flow equally in low temps, but in high temps, the 5w30 would perform better.

Should this be a concern to you? Yes, it should be a concern to you. Auto manufacturers have specific reasons for recommending a particular type of oil for their [different] engines.

Mostly, on newer cars, the engines come with 5w20 specifications, while you would mostly see 5w30 specifications on older cars.

With all that is said so far, here are the main takeaway points regarding these two motor oils.

  • The 5w20 would flow easily at cold temps (usually during winter), but it’s likely to thin out in high temps.
  • 5w30 is better and recommended. It flows easily too (just like 5w20), but performs better in high temps because it has more weight “30” as against “20” in 5w20.

But what could happen if you mistakenly pour 5w20 into your engine that uses 5w30?

What Happens When You Accidentally Put 5w20 Instead Of 5w30?

What Happens When You Accidentally Put 5w20 Instead Of 5w30

Nothing too harsh would happen. Yes, your engine won’t blow up (not even after some days). Mixing oils typically reduces engine performance, reduces fuel economy, and possibly causes sludge inside the engine.

Now, these possible issues that may occur from mixing motor oils cannot damage your engine; they’d only make driving uncomfortable – not as fun as it used to be – and reduce the interval between oil changes.

It’s beginning to sound scary right? Well, there’s nothing to worry about. Put simply, pouring 5w20 instead of 5w30 is the same as mixing a 5w20 oil and 5w30 oil, and then pour the blend into your car.

So, it won’t hurt your engine immediately, but over time, you may begin to notice several uncommon signs, a significant drop in performance, and other unusual signs that show you’re not using the best motor oil for your engine.

Therefore, it is advisable that after you mistakenly pour 5w20 instead of 5w30, you should drain out the oil and refill the recommended one for your engine.

If you leave the 5w20 in your engine, it’d try to mix the remaining 5w30 in your oil reservoir; thus, none of the oils would deliver maximal protection to the moving parts of your car engine, which can, in turn, cause a serious problem in the long run.

What More?

If you’re scared that you’ve voided the warranty on your car because you used 5w20 instead of 5w30, this is what you should know.

No one – not even your manufacturer – can immediately detect the exact oil you poured into your vehicle; however, except they take the oil for a test.

That said, except you tell them what you’ve done, your warranty would still be valid. Now, asides from warranty concerns, 5w20 would absolutely not harm a 5w30 engine because they deliver almost the same performance.

You should only be concerned if you drive in areas with high temperatures (or deserts, chuckles).

So, in summary, if you accidentally put 5w20 instead of 5w30, simply wait till your next oil change, drain the 5w20 and continue with your 5w30.

Related Articles:

Scroll to Top