When does my car need an oil change? I’m getting different answers from these two mechanics

Dear Ask a Mechanic,

I’m a first time car owner and I know nothing about them.

I have a 2019 Honda CR-V. Mechanic One, who does my oil, said it takes full synthetic.

I usually go to Mechanic One for oil changes. When done, they reset the oil-life indicator. Last time I got an oil change was 53k. I was told full synthetic gets 12,000-plus kilometres. The car has around 66,000 now, so, yes, I’m a little over.

I brought it to a different mechanic due to their proximity to my work. Mechanic Two said that the oil gets 5,000 kilometres to 8,000 km, and that my oil was dark and gross. Their oil change sticker says I should go back at 72,000. Also, they said I needed an engine flush.

Is Mechanic One or Mechanic Two taking me for a ride?

Oil Be Fine

The service life of engine oil (and other automotive fluids) is a regular talking point with our customers. As you note, your Honda has a built-in service reminder system, and it has the ability to notify you of the need to perform service on or replace several different items, engine oil and filter among them.

The type, or even presence, of built-in maintenance reminders varies by automaker and model; Honda’s “Maintenance Minder” uses mileage and time for some items, while driving conditions (trip length, temperature, load conditions, and so on) are factored into the estimated service life of others.

As a result of having this on-board electronic system, Honda doesn’t provide specific intervals for most of its maintenance items, including engine oil. Based on what we see in terms of calculated percentage remaining and distance since the previous change, Honda appears to allow intervals of 12,000 kilometres or more, so Mechanic One is telling you the truth. Lengthy intervals are quite common in the industry; the traditional 5,000-km. oil change is no longer the norm.

Mechanic One is also correct about the oil being synthetic. Regardless of which engine it has, the 2019 CR-V uses 0W20 oil, which, to the best of my knowledge, only exists as a synthetic product.

Lest you think that Mechanic Two is suddenly suspect, know that not every tech agrees with these extended drain intervals, including me.

Toyota’s schedule for my wife’s 2020 4Runner calls for an inspection and tire rotation every 8,000 km., but oil changes only every 16,000. As we keep our vehicles for 10 years or more, and they’re used mostly for either short commutes or towing our camper trailer — this use I consider “severe” — the oil (coincidentally 0W20) gets changed every 8,000 km. If it was a lease or I didn’t care about long-term ownership, I’d likely just follow the factory’s schedule.

I seldom recommend engine oil flushes outside of circumstances where contamination has occurred from a mechanical issue, however Mechanic Two’s desire to shorten your interval based on the condition of your oil has some merit.

We’ve observed that direct-fuel injection systems, such as that in your Honda, appear to load the engine oil with unburned fuel and carbon substantially during cold-start operation, so gasoline direct injection (GDI) vehicles that experience mostly short trips frequently have visibly dirty oil (often with a noticeable gasoline odour) well before their indicated replacement times.

While visual condition alone is not grounds for change, most of our clients are keeping their vehicles well out of warranty, so we’ll recommend shortened intervals as seems fit based on our observations and specific needs.

Ask a Mechanic is written by Brian Early, a Red Seal-certified automotive technician. You can send your questions to wheels@thestar.ca. These answers are for informational purposes only. Please consult a certified mechanic before having any work done to your vehicle.