Hi,

My wife’s Koleos is now approaching 100k miles (160000 kilometers) and we’d like to keep the car as long as possible, 200k miles minimum.

Lately I’ve been doing 20000 kilometers oil changes (8 liters) with whatever ACEA C3 oil I can find cheap/on sale. Doing this since the 80000 kilometers mark. Before this, I was using Repsol or Q8 ACEA C4 oils, changed every 15000 kilometers.

To increase significantly durability, should I:
-reduce OCI to 10000 kilometers ?
-use some Castrol Edge or Magnatec, Motul 8100 ?
-go with 5w40 instead of 5w30 ?
-switch to low saps HDEO ?

Don't know anything about your car, but 10K (miles) OCIs have worked well for me for the life of my engines(as long as I have owned them). I have put many miles on my vehicles in the last 40 years(200-350K) and never saw any sign of engine wear, oil consumption, or sludge. With a quality synthetic 10K should continue to work well for you.

I would stay with whatever routine has worked well to this point.

Every 15,000KM is just fine.

I really do NOT think there's much you can do: "To increase significantly durability"

The entire circumference of Réunion Island is just a bit over 100 miles -

(
The island has a coastline of 207 km)

Where do you go to drive some many Miles?KM?

I try to coordinate mine to divide the year in two and a change the oil in the spring to get rid of the oil contaminated by the the cold weather starts in Dec, Jan and Feb , then a change in the fall to to rid of the oil worn out by 90 degree weather during July and August. It works about to roughly 10,000 km, (6000 miles) each session which happens to agree with my OLM.

As always, I can hardly wait to change it.

There: Where wife's work

And to get there it's a 20 miles each way commute

Engine: Renault-Nissan M9R, 2 liters L4 intercooled-turbocharged high pressure commonrail diesel, tuned to 280 lb ft @ 2200rpm, max power before pedal remap was 200 hp @4000 rpm. EGR off. DPF still here.

Shortening the drain interval to 15K K might help.
Other than that, you can only hope for the best.
I'd probably get on some EU boards and see what they have to tell you about this engine and what it needs to reach high mileage.
Google translator might be your friend here.

I’d too reduce the OCI a bit. No fuel dilution issue?

Other than that, I think with regular maintenance this engine can reach 200K without major issue. .watch the coolant level perhaps, and replace regularly the fuel filter.

I’m also pretty sure OP won’t need google translate to go to French boards...but these might not be the most useful
I don’t know if this engine was sold much in German6 or Russia ?

No fuel dilution issue as I’m aware of (no oil level going up, no gasoil smell in oil, I top up with 1 liter in the middle of OCI) but I have some kind of greasy leaks around the turbo-to-intercooler soft hose.

If I were trying to get 300,000km plus out of modern small diesel, I'd be looking after the fuel system - a fuel pump or injector failure can just about be deemed "uneconomical to repair", and see the vehicle scrapped.

So, I'd stick with your 20,000km OCI, and I'd change the fuel filter then as well. In my Outlander, I use an Australian made fuel additive to disperse water and lubricate the injectors, no doubt you can find something similar locally.

Superflan, late Renault 2.0 dci are strong units. No problems doing 400k km. 500 is possible too. Main problem I see here is short trips. 40 miles per day will not suffice.
C3/4 or E6 will do best.