Do modern Cars require adding Oil on long trips?

[Richard_Pearse]

I have a 2000 Toyota Corolla with 170,000 km. It is serviced every 10,000 km (6,000 miles) and I have never added oil to it. The mechanics have never commented on the oil level being low when they service it.

[bob_2]

I remember that back in the 70s, when motorways made it possible to drive at high speed for long periods, car engines were seizing up because the oil pump sucked all the oil to the top of the engine faster than it could flow back down. The advice was to stop, or at least slow down, every hour or so. Of course this doesn’t happen with modern cars, and I would not expect to be adding oil between changes at all.

[GreasyJack]

@FoieGrasIsEvil

Are you really running at higher RPM’s on the highway, though? Generally speaking, my 2014 Corolla S pulls about 2500 RPM’s at 65mph, which is basically the same RPM level I’m running at 45mph due to being in a lower gear than on the highway (my car has a 7-speed CVT tranny if that matters). I’ve always been under the assumption that the steady, even speeds of highway driving were a lot less hard on your engine and transmission than stop and go driving.

Is that not correct?

It might be a little different with CVT’s or conventional automatics with a lot of gears but in general an automatic will shift into its highest gear at around 45. Yes, in stop-and-go driving your RPM’s get higher, but only when you’re actively accelerating. When you let off the gas, the transmission will upshift. It’s the combination of high engine speeds with light throttle that leads to high vacuum and worsening oil drinking, and that pretty much only happens with highway driving.

@HoneyBadgerDC

Manifold vacuum is not higher at highway speeds unless you are decelerating with the throttle plate closed and engine rpms high.

Is your foot on the gas the whole time when you’re driving on the highway? With most cars, it only takes a tiny amount of throttle to maintain speed, so the vacuum will remain high. Plus, yes, you probably do quite frequently decelerate with the throttle plate closed unless you’re a tailgater.

[GreasyJack]

@FoieGrasIsEvil

I’ve always been under the assumption that the steady, even speeds of highway driving were a lot less hard on your engine and transmission than stop and go driving.

Is that not correct?

Oh, and to specifically address this, yes highway miles are generally much easier on your engine and transmission, it’s just that if you DO have an oil consumption problem, highway driving is where it will manifest itself the most.

[excavating_for_a_mind]

@JerrySTL

The theory of how much oil a car should use and the actual use could be different. Very different and that could be expensive if you run an engine with a low oil level.

You have to put gas in the car about every 300-500 miles. I suggest taking a couple of minutes and checking the oil (and brake fluid, coolant levels, etc) every second gas stop.

And don’t forget to check tire pressures at least once a month and the spare tire every 6 months.

^This.

There are many reasons an engine will “use” oil. Even brand new engines. It does not mean the engine is worn out or that it is defective, only that it “uses oil”. It is true that on older engine, oil consumption can rise because of worn engine parts or leaking seals and gaskets.

Just because an engine is using 1 quart in 2000-3000 miles does not mean it has not been maintained or that the engine is defective. Simple math will show you that if a car cruises at 60 mph at 2000 rpm, one quart in 2000 miles is well over 4 million revolutions of the engine in 2000 miles. Using 1 quart in that time is about 1 micro-liter (1/1000 of a milliliter) or about 1/100th of a drop of oil (using my HS chem teacher’s estimate of 10 drops to a ml) per revolution.

There is a big difference between 1 quart in 2000 miles and 1 quart in 200 miles. Most manufacturers use the 1 quart in 1500 miles as the cut-off, not because that consumption is ‘good’ or even ‘typical’, but because if there is a problem, you will typically see three times that consumption or more and they need to convince people who see half that consumption that everything is OK.

All that being said, the answer to the OP is, yes, modern cars can require adding oil on long trips. It depends on a lot of conditions, but you need to check the oil level periodically (whether you are on long trips or not) to be sure you are at the proper level.

Same thing with tires. A good tire can lose air pressure over time, even it there are no significant leaks. Expansion with heat, deformation of the rubber when rolling, etc…, can all mean a tire will lose a bit of air. It doesn’t mean the tire is bad (although a big leak does), but you need to check the air pressure periodically to make sure you have the proper inflation.

[kanicbird]

@bob_2

I remember that back in the 70s, when motorways made it possible to drive at high speed for long periods, car engines were seizing up because the oil pump sucked all the oil to the top of the engine faster than it could flow back down. The advice was to stop, or at least slow down, every hour or so. Of course this doesn’t happen with modern cars, and I would not expect to be adding oil between changes at all.

I would think this would involve a significant sludge build up as oil flows pretty darn fast when hot.

[FoieGrasIsEvil]

@GreasyJack

Oh, and to specifically address this, yes highway miles are generally much easier on your engine and transmission, it’s just that if you DO have an oil consumption problem, highway driving is where it will manifest itself the most.

Interesting…thank you. I (and I assume I am not alone) had always thought that the reverse was true. I defer to your expertise.

[california_jobcase]

I had a Vega that did that (who’d a thunk it?). Daily driving would use a quart every 2 1/2 tanks of gas, but highway driving (in the 55mph days) would smoke out a quart a tank. I ran ten quarts of 10w-40 through that engine’s tailpipe the last long trip I took in it.