Changing oil? See how to avoid 4 common mistakes.

20 August 2025 by Tomasz Szymański

“Why should I read this? Changing oil is basic stuff.”
Sure – you probably do it several times a day.

But that’s exactly when small mistakes happen – quick, unintentional… and expensive.

Here are 4 common issues that can sneak in even during routine oil changes. We’ve also included a few simple tips to help you avoid them.

Let’s get into it.

1. Draining cold oil

At first glance – everything seems fine. Old oil drained, new oil filled, filter changed, happy customer.

But if you drain the oil while it’s still cold, a good portion of the old stuff might stay inside the engine.
Why? Because at low temperatures, oil is much thicker and doesn’t flow out the way it should.

And what happens when leftover oil mixes with fresh oil?
Lubrication efficiency drops, engine performance can suffer – leading to higher fuel consumption and faster wear on engine components.

How to avoid it?

Warm the engine up to operating temperature.
Turn it off, pull out the dipstick, and unscrew the filler cap – this way the oil drains smoothly without splashing.

2. Overfilling the oil

It might seem safer to pour in “a bit too much rather than too little,” right?

But that “bit too much” can quickly lead to a tow truck call – or at best, smoke or oil leaks around the intake system.

Too little oil? Also bad.
Not enough oil means low pressure, which can eventually lead to engine seizure.

How to avoid it?

Always check the factory-specified oil capacity – ideally using a verified source.
(And don’t forget to account for an aftermarket oil cooler, if installed!)
Fill the oil in two steps: start with 70–80%, then check the dipstick and top up as needed.
After starting the engine, let it run for 2–3 minutes. Then turn it off, wait a moment, and check the level again.

3. Overtightening the drain plug

Tighten the plug “by feel,” and before you know it – the thread gives out.
Then it’s time for improvisation: silicone, sealant tape, or in the worst-case scenario… replacing the whole oil pan.

Stripped threads are a classic result of “quick service mode.”
And it’s not always your fault – sometimes the plug was already glued in, but no one bothered to mention it.

How to avoid it?

Always clean the thread before installing a new plug – no metal shavings, oil residue, or remnants of sealant.
Replace the washer (or the plug itself) every time – this is essential.
Use a torque wrench. Most plugs require 25-35 Nm. It’s better to check the specs than to guess

4. Using the wrong equipment

No service pit? You’ll manage.
But if your only “tool” is a empty paint bucket, you’re making things harder for yourself.

Hot oil, poor access, awkward angles under the car on jack stands… and suddenly your whole car service smells like burnt oil.
Most burn injuries during oil changes happen in these “quick and dirty” setups without a pit or lift.

How to make it safer and faster?

Working from above? Use a vacuum oil extractor with a probe.
REDATS D-150 or D-220 will handle it in just a few minutes – no need to crawl under the car.
Need to drain oil the traditional way?
Place the car on solid jack stands and use a proper oil drain unit – like REDATS D-300.

Are those all the mistakes? Not even close!

An oil change isn’t just draining the old and pouring in the new.

There are a few small things people often forget – and they can come back to bite you.
Here’s a list of other common issues to keep in mind:

Wrong oil type
The “best” oil isn’t always best for that engine. Always check the manufacturer’s specs.
Skipping the oil filter change
Fresh oil + old filter = bad combo.
The filter holds old oil, contaminants, and metal shavings – all of which go back into circulation.
Uneven car setup
If the car is tilted, the oil level on the dipstick will give you false info.
Forgetting to reset the service interval
Might seem like a small thing – but the customer will be back asking,
“Why is the oil light still on?”
No note of mileage or date
A sticky note or a label under the hood is enough – just record when and at what mileage it was done.
No post-change check
Start the engine, let it run, then check the filter and drain plug area.
Better to catch a leak after 2 minutes than after 2 days and 200 kilometers.
Dry filter gasket
A dry O-ring is a recipe for trouble. Always give it a light oil coat before installation.

Too long between oil changes

City driving: change oil every 10,000 km
Highway driving: every 15,000 km
Infrequent use: change oil once a year, even if it’s only covered 2,000 km

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Summary

An oil change is routine work – and that’s exactly why it’s easy to overlook something.
And when that happens, you end up doing the job twice… or dealing with a frustrated customer.Most of these mistakes can be avoided with good habits – and with tools that make the job easier, not harder.