5W30 or 5W40 (or other)
 

So I have found some places to buy some motul oil, and they only seem to have 5W30 and 5W40 (from what I have seen)

So I recently bought a used 1998 Kouki 240sx with a stock KA24DE engine (120,000 kms), and the previous owner told me he always used Motul oil for oil changes so I decided with that brand.. but the thing is which one is better for my engine the 5W30 or 5W40? Completely noob at this so I have no clue. Thanks!

What other mods does the car have? What are you going to do with the car? DD? Track?

Go 5w30 if the car is stock and/or you are just going to DD the car.
Plus summer is over so it isn't going to be that hot for you to need a 40 weight.

Car is a daily driver, only mods are a exaust and high flow air filter. Nothing special

So during the cold days I should go 5W30.. Should I switch to 5W40 during the summer? Or should I stick with 5W30 all year round? Thanks

5w30 year round is fine. Our summer's are mild enough that you really won't need a 40 weight unless you are tracking the car where there is going to be a lot of heat.

Alright thanks! Also do different filters make much difference? I just picked up a NPN Oil filter that fits my S14 (no clue if its good or not), now thinking of changing for a better one.. is that nessessary?

Also about the mild summer thing, i dunno man some days got pretty fucking hot this summer LOL, I also autox during the summer from time to time.. is it still okay to stick with 5W30? Thanks

Also I have heard that running 1 level thicker oil for a older engine is better, what does that mean?

Anyone?

people think that running thicker oil on older engine is good because older engine tends to burn or leak oil. but running thicker oil doesnt actually SOLVE the burn or leak of oil. So it really isn't a fix. I suggest running 5W30 and checking the oil lvl frequently. if you drive HARD or autox alot, its also good to change your oil more often.

the only reason to move up oil weights is to maintain oil pressure as oil temps get really hot.

depends on your engine, if your engine is prone to fuel dilation, 5-30 oil could easy shear down to 5-20, but for anything else, 5-30 is your best bet.

5w30 is the way to go in your situation. 5w40 is more a diesel engine oil as diesels run hotter, hense the 40 weight. The 2 numbers represent 2 different things. The first number, in your case 5, indicates the oils viscosity at 0 degrees or when the engine is cold. The lower the number here, the better the flow at colder temperatures. This is why you will see sinthetics run at 5 or less in this location. It is the oils abitity to flow in the cold.

The second number indicates just the opposite. It is the oils ability to flow (or viscosity index) at operating temperature. Diesels and other high compression engines run the highers due to the heat and power they produce. Cars and light trucks can get away with a lighter oil in this situation as they don't work as hard or get as hot. 30 weight is the norm with some using 20.

If you are still uncertain, look in your owners manual and use the manufacturers recommended fluids.

As for filters, they are all made from only a handfull of manufacturers. So most filters you will find are made at the same factory. The specs however may vary from one to the other depending on the order and who it is made for.

I run donalson in all my vehicles as they are one of the better ones. To check what you are running, take a filter cutter, or hacksaw if you don't have one, and cut the top off the filter and pull it apart. Check the pleeting, a good filter will not be colapsed and most likely have either a fiber type rope or ring of glue in a few spots of the filter keeping the pletes separated for maximun filtration.

Yup, I changed with 5W30. Thanks for all the help everyone