Are prolonged interstate speeds (78-79mph) hard on small 1.5L engine?

Highway miles are the easiest on oil. I would follow the Honda MM, but make sure and check the level every few tanks. Others WILL differ on this, there are lots of 200 post discussions on oil change intervals. Let’s see if this becomes another one…

I think your Honda MM would know best, to be honest. The only thing I would do differently is spend a little extra and run synthetic vs. conventional for peace of mind if going upwards of 10k on an OCI. Either way, I’m sure your engine will be fine for years to come.

I agree with the others. Your Honda will do just fine at those speeds. I have an old 91 CRX that gets redlined almost every shift and has been driven all over the place, including race tracks, and I’m at the point where I wish the freaking motor would die so I’d have an excuse to put something bigger in there, but it just won’t. It’s very common for the rest of the car to fall apart around the engine.

I don’t even think you need to run synthetic unless the manual calls for it, and as long as you keep up with the oil changes.

Your engine will be fine, but check your oil level regularly. With the new 0W20 oils, high speed will means likely some oil consumption; nothing to worry about, but check it regularly.

Even though your owners manual doesn’t specify synthetic I would definitly use it if you’re going 10K miles between changes.

Leave a little earlier, go the speed limit, and your gas savings will pay for your gym membership.

Count me in too. Remember the Corolla 1.8 was drafted by Lotus as a sports car motor and Honda pioneered making a 1.6 with over 160 hp without turbo. Honda makes some of the most reliable high rpm motors there are. They have to make cars that will cruise on highways with unlimited speed limits. Under 80 is a cake walk. I will would take that bet that the motor will outlast the rust that will appear on your car at some time in the salt belt.

I had a buddies father who had quite a history in car racing and flying tigers etc. Now back in the 70’s I remember his quote, “It does not harm a good engine to go fast”

The only issues in my opinion are the 10k miles oil change intervals and the potential of allowing the oil level to drop.
My preference would be 5k miles intervals and checking the oil level every 500 miles just to be on the safe side.

All pretty good comments by the other posters, my commute is similar but my hours as a college professor are somewhat flexible so I don’t have to speed to get there, so I’m usually at 60-65 turning 2500-3000. The mpg will drop at higher speeds but the engine will handle it well. Two things that I didn’t see mentioned here . . . you’ve got to be careful at 80 mph, stuff happens fast at that speed and accidents happen. Also, your brakes and exhaust will last almost forever, the exhaust will heat to the point that all moisture will be cooked out daily, a good thing. Your brakes depend on how you drive, but all highway will give you high miles between brake jobs. Careful driving at that speed, good luck! Rocketman

As others have said, the engine was designed to do exactly what you’re doing. Since the Fit doesn’t have a timing belt, you don’t even have that to worry about.

It doesn’t appear here:

It’s such a perfect Fit, it’s practically a convulsion.

rocketman - very cool point about the exhaust and heat. Also, I will slow it down : )

On my 100+ mile commute I always tried to use a comfortable car and a V6 or a V8. I always got many hundreds of thousands of miles on mine with regular (3000) oil changes. 200K, 300K, 500K etc. That’s what I did and I’m happy I did it that way. It just too much time in a car to not be comfortable and the dollar difference between 30 and 40 mpg is not all that great. Just me though.

You put 400 miles on your car every week commuting. The weekly total is probably more like 500 to 600 miles. Check your oil level every week or every other week. If you used a little oil before, you will use a lot more now and should check level more often.

You put 400 miles on your car every week commuting.

Should be 850 miles, per OP.

OP . . . I’m serious about the exhaust and brake issues. I retired my '89 Accord with 585,000 miles due to underbody rust but I remember going 75k for front brakes (disc) and 150k for rear (shoes), and can only remember changing exhausts 3 times, I went to an aftermarket which was thicker metal and it lasted forever. Getting your exhaust hot enough to cook out the moisture is a big deal, highway miles are easy on a Honda. Mine still ran great when it was retired. Careful driving 80 mph, stuff happens fast at that speed. Good luck! Rocketman

Thank you all for commenting! I have learned a lot reading through these responses.

A synopsis of responses for those that are curious:

Tips on the Engine/Car:
(A) - Honda has a history of great engine designs that can handle high RPMs
(B) - Engine may wear a little faster but will still likely outlast the car
© - 9-11k oil change may been too much without synthetic oil
(D) - Check oil every other trip the pump along with an inspection of the tires
(E) - High speeds with new 0W20 oils will result in some oil consumption, check oil regularly!
(F) - Follow Honda recommendations for maintenance, consider more frequent oil changes
(G) - Under 80mph you should be fine, cars are designed for driving!

Tips for long commutes:
(A) - Tires can make a huge difference in ride comfort (find balance of soft/efficient is the trick)
(B) - Sitting for long durations is hard on your health, join a gym and make it a habit to go!
© - Going 8-9mph is a bit much, both in terms of fuel efficiency and safety
(D) - Exhaust won’t collect moisture due to heat and this could help the exhaust last longer.
(E) - Prius won’t do much better at Interstate speeds, might not be enough savings to justify.
(F) - Speeding tickets are expensive, stick to 4-5mph over and avoid the insurance hike!

Thank you all again – glad to have joined the CarTalk community!

I feel way better with this additional information. Had no clue that “oil consumption” was a thing but it makes sense. I will slow it down for safety’s sake and join a gym for both my body and mind.

Biggest annoyance? 10 gal tank and my commute uses 5.5-6.0 gallons per day…so daily trips to the gas station (yippee).

Quoted MPG numbers from car makers are based on 55 mph. The US DOE studied mileage vs speed and the results show that, typically, 80 mph decreases fuel mileage by 28%. Ouch. Remember that wind resistance increases with the square of the speed (an exponential increase). This has been borne out by a hurried 120 kph (75 mph) drive I did a couple of years ago, instead of my usual 90 kph (55 mph). The mileage was almost 10 mpg less. Didn’t do that again. Having a big roof rack (Thule ski box and 2 Yakima bike racks) and driving the mountainous roads of BC already puts a nasty hit on the mpg.

I plugged your numbers to the below calculator. 33mpg; 170 miles/day; $3.50/gallon
At 55 mph, you spend $6,581 in fuel per year. At 80 mph, you spend $9,125 in fuel per year, but you do add 34 minutes/day to your commute. Double Ouch. Moinfo at

I plugged your numbers to the below calculator. 33mpg; 170 miles/day; $3.50/gallon At 55 mph, you spend $6,581 in fuel per year. At 80 mph, you spend $9,125 in fuel per year, but you do add 34 minutes/day to your commute. Double Ouch. Moinfo at

You’re making an assumption that he has that commute 365 days a year. On average a normal job only requires you to drive to work 237 days a year. I’d expect that the other 128 days he’s not driving 170 miles. Probably around 50 is a good guess. When you recalculate the numbers drop a lot.

I liked this discussion. Everyone is so nice. I have a Korean-made car with a small engine, so I am glad to know this also.