2.0 HDI(90) 5w30 or 5w-40?

[Neger_Emerson]

Hy Guys!

The engine is a 2.0 HDI(90) DW10TD RHY from 2002 with 390,000km(242,334miles). The service book lists two oils Total Quartz 9000 5w40 and Total Quartz 7000 5w30
I am going to change the oil in my car now, I have been using 5w40 for about 20 years but the mechanic recommended 5w30. My question is is 5w30 better for it and if so why or should I stay with 5w40.

[wurlycorner]

Did the mechanic say why they recommended changing?

If the manual lists both (and it’s the right manual for your car and your country) then both will be fine/neither will wreck the engine. But for what it’s worth…

I have a DW10ATED (same engine but the intercooled 110bhp version) with around 240k miles on it.
Have always run 5W-40 (I’ve done over 100k of those miles) and the engine is in tip/top condition internally from what I can tell - I changed the rocker cover at around 200k and there was absolutely no wear on the cam lobes.
I’d be wary of going down on the ‘hot’ viscosity (the 40 v 30 scale) on an older engine, so my advice is stick to 5W-40 - though it depends on your climate there, generally warmer country equals thicker ‘hot’ base oil viscosity, colder climate equals thinner ‘cold’ base oil viscosity. I think Hungary has a slightly warmer summer climate than UK? In which case that further supports not dropping the hot viscosity,

More important overall is the quality of oil and filter going in and to not extend the service interval.

[PaulC5]

Since it has managed 23 years and 390k km on the 5w40 oil I would stick with it. The thinner oil might give a slight increase in fuel economy but if there is wear in the engine any oil consumption might increase. If you are paying the mechanic to change the oil then possibly he/she has 5w30 in stock and wants to use that.

[Mihael_M]

According to the Stellantis document, both 5W 30 and 5W 40 can be used. I would pour 5W 40 if the engine is quite old and a thicker oil would benefit it better.