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can I use 10w40 instead of 5w40??
- Thread starter rsvmad1
- Start date
thanks mate
Evo 5 RS
lol considering most mk2s probably blow most of it out the back anyway now I'd say you'd be fine
He said that they have 10w40 but not 5w40
Noticed my spelling mistake after, but couldn't edit the post!
Can you fill us in on the details of what will happen to the engine that is a negative effect then please
Aslong as its fully synthetic it will be fine. 5w - 40 will be better for warmer conditions, 10w is thicker to start with thus doesnt get to places around the engine as quickly as 5w-40, but it all depends on temperature.
If it was a 172/182 id run it on 5w-40 fully synth myself.....
If it was a 172/182 id run it on 5w-40 fully synth myself.....
Fixed.
Lower the first number, thinner it is when cold, therefore quicker it circulates in winter.
10W should be fine for everything outside the very depths of a proper freezing winter in the UK. 5W just gets round quicker first thing in the morning, but shouldn't be so thin as to cause damage from part-on-part friction.
As long as you're not running 0w30 Mobil1 or something ridiculous, which is only suitable for ultra-small tolerance engines, you'll be fine with either 5w40 or 10w40.
Last edited:
Mk4 Mondeo Estate
It's all to do with the viscosity (resistance to flow) which will also affect the boundary lubrication (fine film of oil that clings to components) if the engine grade isn't right in can affect these fine tolerances and not lubricate the engine sufficientlyCan you fill us in on the details of what will happen to the engine that is a negative effect then please
Went to my local Renault garage and they recommended 10w40 semi not fully.. summet to do with the engine 10 years old and engine wear etc.. just what they recommended dont shoot the messanger
They are probably able to put a higher mark-up on cheaper oil :/
The problem with a 5w40 on a decade old engine is that the fine tolerances you are talking about are now all a lot less fine than they used to be, so as a result an oil with a slightly thicker cold grade will allow you to generate pressure in fewer turns of the crank when cold starting.
So like I said, the 10w40 is probably preferable now that everything is worn.
Also you have to remember that oil dilution from fuel becomes more of an issue over time when the rings are worn, so this leads to a breakdown of the oil, so when you first put your 5w40 in it might be working ok, but at the end of its 10K or whatever stint in the engine it will be fuel diluted more than was intended on a new engine.
Amazingly in this case apparently even renault have worked that out which I must admit surprises me as normally they know naff all about their own engines, lol
bozothenutter
ClioSport Club Member
At what mileage would a switchover be prudent?
There are no hard and fast rules, it really depends on the life the engine has had and how its worn.
As a general guideline though, if its started to breath a bit, thats a good time to think about a slightly thicker oil IMHO, so for example I run a slightly thicker oil in our 172 as that now breathes a bit with 140K on the clock.