Oil change interval?

[laurent_caen]

practical question: who knows why on modern cars the oil changes are much more spaced than on old cars?
another question: is the production of 1 liter of oil more or less polluting than the production of 1 liter of diesel and in what proportion?

[Christophe]

practical question: who knows why on modern cars the oil changes are much more spaced than on old cars?

Short answer:

It is not so much towards cars (although the improvement in machining, thanks to the digital technology, and materials allows much better adjustments) but towards oil that we must turn to: they are of much better quality. (thanks to new additives in particular ...) than those of 20 years ago ...

I leave it to a better engine specialist than me (Bucheron for example) to make a more complete answer ...

[laurent_caen]

thank you for this simple and clear answer
if I understand correctly, an old car that would be drained with "modern" oil could do more km than the manufacturer's recommendations at the time of the car? unless there is a pb of compatibility of the oil?

[Christophe]

unless there is an oil compatibility bp?

In theory yes it is possible, but it all depends on what you call old ... An engine is designed for an oil of a certain viscosity ...

For example, on engines over 5 to 10 years old oils (given for low consumption) with a low hot index of 0W20 or 0W30 must be avoided, the hot fluidity is far too low to create a sufficient protective film. ..

[Other]

Hello
Controversial subject.
changing the oil at 10 km is an aberrence, it is marketing for the sale of cars as elémer maintenance greasing ect .. it is true if one intends to make 000 km and sell the vehicle, I live with these old vehicles.
Certiane person of emon entourage bought a new V8 car
he never changed the oil or the filter after 40 km he resells the vehicle and their opinion (no problem) yes but whoever buys that, he will put all the oil that this without drawing did not want to put, finally he spends his time putting in and he too does not drain any more ..
It's not the km that determines when to change the oil
this is the use we make of the vehicle.
the oil apart from its fluidity although now we have a wide choice of multigrade it is used first to grease the bearings and the piston piston, it is used to cool the underside of the pistons (the turbo diesel has a small hole to make attach oil under the piston, and above all it is used to clean the segment grooves,
(that's why the oil quickly turns black on diesels and even more on fuel oil)

A vehicle which makes many starts and small runs in winter. Its oil becomes contaminated with water and fuel which at each start penetrates through the segments, to eliminate this mayonaise water and gasoline it is necessary that the temperature of el oil exceeds 100c when there is water in the oil, it has difficulty in exceeding 100c
therefore consitant journey in winter.
The rule here it is in spring some is the km we make the emptying
Normally you have to change the oil once a year in an engine even if it has very little can roll (risk of ecorrosion on the bottom of this cylinder and even more particularly with new synthetic oils this is one of the reasons that 'it is not approved in aircraft engines).

we will be told yes there is a good filter ..
after a while the filter becomes partially clogged and at the bottom of the filter there is a calibrated spring when the pressure increases the cartridge rises and all the accumulated dirt passes straight into the system the filter is bypassed (better dirty oil no oil) for the pistons (it is tolerable) but for the bearings unacceptable)
A test easy to do on an engine of a certain age which has been well maintained, when you change the oil the engine remains stable it practically does not consume it, when it starts to consume it
this is what is contaminating it has lost its qualities, either that we add or that we change it, it is a choice.
but calculate the quantity of oil required over 100 km either change it regularly or add more,
those who change it regularly in total use less oil than those who add it. (because when you start adding more you will always add more damage is done)
The difference between a healthy engine and a worn engine is a thin layer of metal that has gone off on the cylinders.
I dismantle all my oil filters I open the accordion to examine metallic or carbon debris.
Personally I change the oil in good summer condition at 5000km and less in winter my vehicle has a 230 km and the other 000 I never add oil between oil changes,
(for those who roll with frying oil it is preferable to change its oil more often, the dilutoin due to this oil does not get rid with heat and it does not come out through the breather)

Many engines have a bad design of the breather, it takes a good system of PCV valve to ensure a good ventilation of the crankcase to maintain a clean oil

It is better to put a good quality intermediate oil and change it more often, than to fall asleep with a super oil that costs 4 times more expensive and change it at 10 km and more as specified by these oil manufacturers,
it is true it is still lubricating, but it is no longer cleaning enough and the filter has its limits especially that the tendency is to put filters not much bigger than on a motorcycle in a V8!

Andre

[denis]

I confirm, a last generation top oil, will be too fluid: the oil pump will not be able to put such a high pressure, the games of modern engines are not as important. In addition an old oil pump, will have even more difficulty in mounting pressure, for the old engine a 15/40 low of game is advised

[nialabert]

In addition, modern oils are detergent. On an old engine, cleaning can reveal leaks that grime clogged.


Finally this is what I was told.

And an article on oils, motorcycles, but it's interesting.
http://www.triumphall.com/huile1.htm

[Christophe]

And an article on oils, motorcycles, but it's interesting.
http://www.triumphall.com/huile1.htm

Motorcycles and cars are the same!
Even diesel oil and petrol is pure marketing (with some exceptions ...).

It was the article I had read in 2004 and to which I referred a little while ago in another post: it is not the oils of big brands which give the best results. However, I am still surprised by the very good quality of Leclerc oil ...

[nialabert]

And an article on oils, motorcycles, but it's interesting.
http://www.triumphall.com/huile1.htm

Motorcycles and cars are the same!
Even diesel oil and petrol is pure marketing (with some exceptions ...).

[...]

I do not agree at all, these oils are very different and in any case on one point: ............ Motorcycle oil is much more expensive

[Other]

Hello
Many Harley enthusiasts use the same oil that we put on airplanes, it's w 20 50 aeroshell from semi synthetic. Its particularity is to resist heat well (it is not uncommon for it to go up to 120c on an airplane, the other particularity is oil without ash, we have operated airplanes which consumed 1 liter on time for a fairly long period
, when disassembling the engine was not erased, even surprising the piston as a two stroke. It takes the case of oil in the luggage compartment, at each landing we check the petrol and we fill up with oil !!
Normally consumption is one liter every 5 hours
Andre