I'm getting the bits and pieces for my service, and need to know what oil I should be running. I went to Halfords, they told me 5w30, went to Castrol - They said 5w40. Looked around the forum - ppls are running 10w30. What do these numbers mean and which one should I run?? I'm leaning toward the 5w40 by Castrol (as its a good make) I have a 1 litre 2ndfacelift coilpack if that's any help....I think, don't quote me on this, all the oils will actually be fine, the numbers have just got something to do with the temps I think....correct me if i'm wrong??
Service oil
- Thread starter -Naqshbandi-
- Start date
Enuo
Glorified Electrician
first number is how thin the oil i, last number is temp range. So 15w40 is thicker and works at hotter temps than 10w30. If your engine has a fair few miles on it i'd put 10w in it, 5w for a fairly new engine. w30 for cold half of year, w40 for hotter half. Also, if you run a fast road sort of engine and drive hard, add 10 to the second number.
My spitfire said 20w50, but I ran 15w60 because engine was rebuilt to tighter tolerances and was driven hard.
This is just a rough guide, don't take it as gospel.
My spitfire said 20w50, but I ran 15w60 because engine was rebuilt to tighter tolerances and was driven hard.
This is just a rough guide, don't take it as gospel.
I've always had 10w 40 in both my 1.0's and now my 1.5 dci 
The numbers have something to do with the viscosity at different temperatures...you ideally want a lower low number and a higher high number, if that makes sense
EG: generally speaking... 10w 40 is "better" than 10w 30 as it has a wider...ummm....working range? it's still good at higher temps...I think
well, that's my understanding anyway, I could be wrong LOL
...this may help? http://www.machinerylubrication.com/Read/171/oil-can
ETA: Enuo beat me to it as I was typing...I need to type faster ^_^
The numbers have something to do with the viscosity at different temperatures...you ideally want a lower low number and a higher high number, if that makes sense
EG: generally speaking... 10w 40 is "better" than 10w 30 as it has a wider...ummm....working range? it's still good at higher temps...I think
well, that's my understanding anyway, I could be wrong LOL
...this may help? http://www.machinerylubrication.com/Read/171/oil-can
ETA: Enuo beat me to it as I was typing...I need to type faster ^_^
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thanks for the speedy and detailed info guys. Much appreciated
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My engine has done 70,000 miles (last weekend) is this classed as old?? in Nissan engine life I'd say it's young (JDM FTW
)
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....think I might just go 10w30 as there's a 5 litre bottle of the stuff sitting in my shed and its blimming winter temps in April!!, It'll save me a few pennies too.... with the saving I might invest the denso iridium spark plugs
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I thought the iridiums were better? anyone tried them? they are like guaranteed for 50,000 miles or suchlike, but that said ngk's are cheep, and cheap is what I like (only got a micra after I was hit by a polish driver in my corolla, he raped my insurance as I couldn't prove anything, now cant afford insurance on anything else- rant over) bosch super 4's any good?
Enuo
Glorified Electrician
I'd say an old engine was 100k miles, you can assume the engine will be quite loose by that point. Oh, and don't think that a higher second number means better protection necessarily, the higher the second number the more viscous it is when cold, putting more stress on oil pumps. If it's mechanical not electric, excessive revving when cold could over stress the vanes on the oil pump or damage the drive gear.
Edit: Adding my opinion on spark plugs, NGK's are infinitely better than champions. I had champions once, somehow changing the oil caused the car to start running on 3 cylinders. Changed the plug and was fine. Switched to NGK's and had no problem. Can't say much for iridiums, but don't go for multi prongs. You won't get multiple sparks that's bull, as long as one gap is microscopically shorter than the other it will take the shorter path. The gap will just stay in the serviceable range for longer as there are more prongs to erode..
Edit: Adding my opinion on spark plugs, NGK's are infinitely better than champions. I had champions once, somehow changing the oil caused the car to start running on 3 cylinders. Changed the plug and was fine. Switched to NGK's and had no problem. Can't say much for iridiums, but don't go for multi prongs. You won't get multiple sparks that's bull, as long as one gap is microscopically shorter than the other it will take the shorter path. The gap will just stay in the serviceable range for longer as there are more prongs to erode..
The smaller number is how thick the oil becomes at cold temperatures (the 'w' stands for winter, not weight), the higher number is how thick it is at full temperature. Nissan recommend 5w30 for virtually all their cars because 5 is thin and gets around the engine more easily on start up when the engine's cold. This is vital for protecting the cams and other upper engine components. They recommend the 30 for fuel efficiency reasons - it creates less drag within the engine than 40, or 50.
I use 5w30 in winter and 5w40 in summer in my diesel. To put all this into context, the Americans are starting to go to 0w20....
The higher second number has nothing to do with cold viscosity, the first number does ie a 5w50 would be thinner at cold temperatures than a 10w30.
I use 5w30 in winter and 5w40 in summer in my diesel. To put all this into context, the Americans are starting to go to 0w20...
.The higher second number has nothing to do with cold viscosity, the first number does ie a 5w50 would be thinner at cold temperatures than a 10w30
.
OP
OP
I think for this years service, I'm going to go for the oil in my shed and switch up next time, as for spark plugs - might as well go NGK as you can get the four plugs for a fiver, if the expensive ones are promising more than they're worth, I might as well make the saving
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how so? NGK are thought to be very reliable??
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....didn't realise that was in Haynes ....but if I didn't have the background knowledge from this thread I wouldn't have understood it so
....but if I didn't have the background knowledge from this thread I wouldn't have understood it so 
