Is driving in B-Mode causing fuel dilution in your hybrid engine?
In this test, I reproduced engine oil dilution twice on my Bigster 1.8 Full Hybrid. Driving exclusively in B-Mode caused the oil level on the dipstick to rise significantly in just 5,000 km, while D-Mode kept the level stable.
While these are personal findings and not lab-confirmed facts, the correlation is clear.
If you own a Dacia or any Renault 1.8 / 1.6 Full Hybrid, check your oil level and let me know if you’ve observed the same thing!
#documentary #automobile #car #suv #dacia #bigster #storytelling
🚙 Project Car
Car: Dacia Bigster Journey
Engine: 1.8 Hybrid 155
Manufacturing year: 10/2025
🎯Goal: Documenting the long-term ownership, maintenance, real costs, etc. while trying to reach 1,000,000 kilometers
📍 Current Checkpoint: 54,342 Km
📅 Ownership period: 7 Months & 3 Weeks
📺 Season: 1 → 0 – 100,000 km
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Hello!
Here's a question: how much oil does your car need when you change it?
Witaj Cristian,
Mam do Ciebie pytanie: czy tryb Eco wg Twoich obserwacji powoduje tylko inny skok pedału przyspieszenia i łagodniejsze przyspieszanie przy jego naciskaniu czy inaczej działają przełożenia skrzyni Multimode i zarządzania energią EV ?
Pozdrawiam,
Piotr
My theory for this, that the “thin” oil mixes a lot easier with E-10 fuel, because of the methanol. Try to use E5 or 100 octane.
It is oil dillution. 🤦♂️
I´d guess that B mode lets the engine cooler than D mode more often. Therefore more room for engine oil dilution. This is the curse of direct injection engines. I´d be surprised if any 1.6 Full Hybrid have had this issue, because 1,6 was indirect injection engine (MPI). Renault experienced its own direct injection fiasco with their 1,2 TCE 85 kW (4 cylinders – not confuse with today´s 3 cylinders, or even ancient 4 cyl 1149 ccm 74 kW). These 85 kW engines were commonly dead after 50 000 km if operated mostly in a city.
I do not understand why using B mode would influence the oil dilution. An answer from a Dacia engineer would be much appreciated.
On the other hand, I think B mode should mainly be used only on long downhill or on slippery roads.
Have you seen any difference in fuel consumption on B vs D mode?
i Hope Dacia/renault are watching this…
i wonder if in B mode they are using fuel in a way out of sync to slow the car down when battery is already fuel and all that unburnt fuel goes trhough the piston rings to the oil
Vă salut!
Văzând clipul dumneavoastră, am făcut și eu o verificare a nivelului de ulei la mașina mea, aceeași cu cea deținută de dumneavoastră, ocazie cu care am observat că nivelul pe jojă este mult peste limită. Merg doar în eco și B, aproximativ 99% din utilizare, iar deja am 22.500 km, iar ultimul schimb l-am făcut la începutul lunii iunie 2026, la aproximativ 17.700 km. Din păcate a fost prima dată când am verificat joja, voi vedea diferența după utilizarea modului D…
I have 7k km and on B mode the oil got up, was doing a oil change. On D the level is ok but the smell is there. The mechanic was telling me that there is no fuel in the oil tank. Got a software update and he telld me to use the safe mode. The engine now gives some wierd sound. After another visit to the mechanic i got a solution from HIM. You should listen to some music.
Jeśli rzeczywiście to prawda to dla mnie to co powiedziałeś tu Przyjacielu to dobra informacja. U mnie poziom oleju jeszcze nie przybywał, ponieważ mam zaledwie 2800km od nowości ale dużo o tym problemie słyszałem i bardzo mnie to martwiło. Jednak, ja trybu B prawie nie używam. Jeśli zatem jeżdżąc na D oleju nie przybywa to będę bardzo szczęśliwy. Co do zapachu benzyny, to benzyna ma bardzo intensywny i ohydny zapach. A zatem nawet naprawdę niewielka jej ilość może powodować wyczuwanie tego zapachu. Myślę, ze nawet przy 20ml benzyny/4l oleju da wyczuć ten ohydny smród benzyny.
I am not different from other guys here. I use B very rare…mainly when going down…in tunnels..where we have section radar ..and the limit speed its a bit crap…but B + ECO together are slowing down the car to a 92-93 km/h…. in town with B I have the feeling that the car doesn't react fast enough…so I don't use it…I don't remember seeing on your board the E-save energy active…and you climbed some mountains 😅 on 25th august I took an appointment for service..second one..at 50.000 km 🤭
Some guy from Horse takes notes while watching this video 😂
I use half and half most of the times when I go to work. I use B mode only when I am in the city and whenever the limit is max 60 km/h and I have roundabouts and intersections close everytime. After that I drive rest of the commute in D mode and only switch back to B mode whenever I meet again roundabouts and intersections.
I did not meet yet dilution but I manage everytime to have 90 degree for the water temp that shows on the screen before I turn my car off. Also I drive highway too which helps I guess.
I recently watched a YouTube video about modern petrol engines and oil viscosity, the information provided suggested that it might be possible to use a thicker oil which helps reduce wear and tear in the engine.
Could this help reduce ingress of petroleum into the engine oil?
Woow that is amazing Cristian. Very useful testing mate! Thanks for that. I am shocked that there is so much difference between the recuperation modes in that context. And it proves that in D mode problem seems to be almost non existant. Which is great news as im not using B mode at all. Not observed oil level rising in my car so far.
Foarte interesanta descoperirea. Eu am achizitionat acum un duster 155 hibrid ..pe care il folosesc doar in b mode pentru baterie. Sa inteleg ca nu e tocmai corect 😅
Cześć Przyjacielu,
Bardzo ciekawe spostrzeżenie. Próbuję zrozumieć co i dlaczego się tam może dziać, że na B paliwo silniej przenika do oleju. Teoretycznie to przecież tylko inny sposób obciążenia rekuperacją…….
Pozdrawiam serdecznie,
Piotr
What are these D and B modes?
Diluția este povara pe care trebuie să o ducă, majoritatea posesorilor de hibrid 😉
Vorba românului,asta e boala lor :))
Spor!
Drum bun.
Mulțumim pentru toate informațiile pe care ni le aduceți.
Vă pot confirma mirosul de benzină de pe joja de ulei, problemă la care am făcut deja un test în reprezentanța Dacia din Nisa fără vreun rezultat periculos (spun ei) și că mirosul este, ca și zgomotul de la cutie (acel cărăit), normal. 😂
Modul B îl activez doar la coborâri, apoi conduc doar în D (am impresia că mașina își păstrează mai mult din inerție, lucru care ajută într-un fel la încărcarea bateriei).
Încă nu am curaj să reproduc testul sugerat de dumneavoastră, pentru că simt că rezultatele ar fi la fel, ceea ce ar produce o schimbare de ulei neprogramată.
Vă urmăresc cu drag.