Dear Car Talk:

Am I negligent? I assume so, since I have not had the oil changed in my 2011 Hyundai Tucson since 2015.

I put lots of short trips on this car, and it doesn’t even have 40,000 miles on it yet.

Yikes, I fear. What say you? -- Steve



Don’t worry, Steve. I’m not going to yell at you or publicly embarrass you. You were right to come forward and ’fess up so we can help you.

Steve, you idiot! Sorry, that slipped out.

As you’ve correctly surmised, what you did is not great. The reason we change our oil every 5,000 or 7,500 miles (or 10,000 or more if it’s synthetic oil) is to keep the engine properly lubricated.

With the metal parts inside your engine rubbing against each other thousands of times per minute, good lubrication is the difference between your engine having a long life and a short life marred by lots of burning oil.

And oil provides more than just lubrication, as crucial as that is. Oil also picks up contaminants and dirt inside the engine and holds them in suspension.

If the oil gets saturated with dirt, and can’t absorb any more, that dirt’s going to stay in your engine. And in the worst cases, we’ve seen more than an inch of sludge in the valve train. Those engines are toast.

You may be lucky, Steve. Maybe the automotive gods were smiling on you, and, despite not changing the oil for the past 20,000 miles or so, there’s no sludge in your engine.

That’d be great. Then all you have to worry about is that poor lubrication will lead to oil burning down the road. And you can solve that problem by selling the car to your brother next week. That’s what I always did.

But if it were me, I’d want to know. I’d ask my mechanic to take off the valve cover and peek in there.

If there’s an inch of sludge in there, you’re either looking at an engine rebuild, or a new vehicle as soon as voluminous plumes of blue smoke start billowing out your tailpipe -- which won’t be long from now.

If the valve train looks reasonably clean, then you should thank your lucky stars, change the oil and set a recurring event in your calendar to change the oil every six months. Then set about 15 or 20 reminders so you can’t ignore it.