Do all you guys generally use 10/40 semi? I only use my car during the summer as I'm sure many of you do, do you find now these engines are getting on a bit a thicker oil is required?

 

Thanks

10w40 semi-synth is what Nissan originally specified mate; so unless you're running big power, there's no reason to change....

 

...Although oil technology has moved on since 1990, so a fully synthetic will offer better stability at higher temperatures. Most readily available fully synthetics tend to be 5w40 - but still a suitable upgrade.

 

This is a reasonable choice....

 

http://www.opieoils.co.uk/p-68977-shell-helix-hx7-10w-40-synthetic-technology-premium-engine-oil.aspx

 

Richard:cool:

Not for me bud, 10/40 is what I use and I run my car all over southern Europe in the Summer; way above British summertime temperatures. lol.

Is the only advantage of a fully synthetic oil being more stable at high temperatures?

 

Thanks, Dan

Is the only advantage of a fully synthetic oil being more stable at high temperatures?

 

Thanks, Dan

 

That and the extended oil change intervals; plus (allegedly) better protection against engine wear......

 

To give you a little comparison, I have usually used Shell Helix Ultra fully synthetic 5w40 in my Z; I drive it around 5,000 miles per year, consequently I have the oil and filter changed annually. And when it was time for an oil change, the old oil (when checking the dip stick) was still always a nice clean gold colour 12 months and 5k miles later.....

 

Last year I took advantage of a special offer and bought some Castrol Magnatec semi-synth 10w40; again a very good oil and more than adequate for the 300zx TT. However I did notice just after Christmas, when checking the oil, that it looked like it needed changing - instead of remaining a nice clean gold colour, it was very dark brown.

 

Needless to say, when I had the oil and filter changed last week, I reverted to the tried and trusted Shell Helix fully synthetic once more:wink: The engine still sounds quiet and smooth - plus the oil pressure is still bang on where it should be at all speeds and temperatures!!

 

Richard:cool:

Interesting observations there Richard, however just to flip the other side of the coin, understanding that oil has many roles some been already mentioned but one is to capture the nasties that are created within a combustion engine, the colour change as the mileage rises is indicative of how much of the nasties the oil has captured neutralized and holding in liquid suspension.

 

Of course this is why oil changes are important so the oil is changed before all of its qualities are exhausted, and that would suggest the semi synthetic oil does a better job of holding the by-products from the engine given its increased colour change as compared to fully synthetic. I know from my Sierra Cosworth days in early 1992 running exclusively on Castrol R fully synthetic it came out the same colour as it went in very often, but it did do 160k miles by time I sold it and was still going strong so it really comes down to personal choice I guess.

 

Jeff TT