Me and my friend were discussing the death of his old car, a Peugeot 207, he believed that constant speeding on the motorway is what caused his car to die.

the UK limit for speed is 70mph, and he would most likely be doing average speeds of 90-100mph on a 220 mile round trip, done roughly every weekend.

It was an average car (probably 70k miles, 9 years old etc), he also admitted that he knows little about cars and was just a hunch or probably what one random mechanic told him.

Knowing my friend personally for over a decade I know he wouldn't have been very "preventative" with his maintenance and would probably only respond to any issue once it had already become an issue, i.e low fluid/oil levels.

His car had pretty much a new issue every week it would be hard for me to constantly name the problems it had, in the end he just got a new one.

I'm hoping to get my first car sometime in the next month and would like it to last for a long time and be well maintained, and was wondering if, in general, speeding (roughly 10-20mph above 70mph) would cause my car to die significantly quicker?

  • 1
    Welcome to the site. I'm not sure there's any real way to answer this question ... not knowing the maintenance history, what type of car it was, or anything else ... this is really broad. People will have different results with different cars with different maintenance. Is driving at 100mph harder on a car than 70? There's a lot more stress put on the vehicle as it is being forced to push an ever increasing mass of air in front of it at higher speeds. Really, proper maintenance of a vehicle is required if there's going to be any expectation of longevity. Commented Jul 22, 2017 at 2:35
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    As Pᴀᴜʟsᴛᴇʀ2 says lots of answers here, but I would go with the prolonged effect of poor maintenance, the are many cars that do a huge amount of motorway miles eg some sales people do 200 - 500 miles each DAY and don't have many breakdowns. It is the difference between preventative maintenance (good) and reactive maintenance (really expensive, reduced lifetime).
    – Solar Mike
    Commented Jul 22, 2017 at 7:11
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    Motorways present the least mechanical issues for well maintained cars - as curves are designed to be gentle, and the road surface is held to a higher quality than rural roads. Maintenance is the issue, I'd be certain.
    – Rory Alsop
    Commented Jul 22, 2017 at 14:38
  • No but it can reduce the life of your bank account!
    – Moab
    Commented Jul 25, 2017 at 0:04

2 Answers 2


It clearly depends on the specifics of the car. If that peugeot had a base 75hp engine he probably literally held the pedal to the floor to go 100mph. Likely engine screaming 5-6000rpm. Yes Id expect that to shorten engine life. The problems to expect would be with mechanicals of course, excessive oil consumption, failing timing chains, etc.

If you want to go that fast look for cars with headroom to spare so you are not maxed out at your cruising speed.


95 mph is only about 150 km/h. I wouldn't consider that fast unless the engine is extraordinarily small.

Power demand is speed cubed. If the car is capable of 175 km/h (all of the cars I have owned are capable of that, some are capable of much more), 150 km/h requires (150/175)^3 * 100 % = 63% of the engine's power output.

My current car, a Toyota RAV4 hybrid has ECO area to half of the total output of the system and PWR area for the upper half. So, you would be slightly in the PWR area continuously for this car. I wouldn't consider that bad. Engines are usually most efficient at 40% of the load, so you are actually only a bit above the maximum efficiency point.

I'd be more concerned about reduced accessory (alternator, AC pump, etc.) lifetime than reduced engine lifetime. Modern engines are pretty durable. But a very cheap alternator or AC pump is not durable at all. That's why I bought a hybrid that has electric AC pump running independently of engine speed and the alternator is actually a very beefy motor-generator; this car has no traditional alternator.

Also, in Germany, the land of the unlimited speed limits, people drive much faster than your friend drives for very long periods of time. Their cars don't die early; in fact, in my country (Finland) it's very common to import used cars from Germany. And in my country, people drive cars until about bit over 20 years old.

In any case, do remind your friend to maintain the car regularly.

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