Hi,

 

I just (yesterdy!) bought a UK Spec Twin-Turbo auto with 137k miles on the clock (and still going strong!). Unfortunately, I do not have an Owner's Handbook (although if anyone has one for sale, please let me know) and do not, therefore, know the recommended spec of engine oil to use.

 

Can someone PLEASE tell me what engine oil is best suited to my car (semi / fully synthetic and what grade e.g. 10w40). I've spent the last hour searching this site and am still none the wiser!

 

MANY thanks!

15w40 semi in mine, good pressure and it doesn't burn any so I guess its allright :p

I use Castrol RS (full synthetic) which I believe has been replaced by another now. I have seen and heard great things about the Castrol Magnatec oil

 

http://www.castrol.com/castrol/multipleproductsection.do?categoryId=9004236&contentId=7007905

10/40 semi synth any brand :D

 

NOT Magnatec or Fully synth

What not fully synthetic ???

Here's some interesting reading backed by real life tests

 

http://neptune.spacebears.com/cars/stories/mobil1.html

Synthetic Oil

 

Advantages

The industry recognizes the following benefits for synthetic motor oils:

 

Improved viscosity at low temperatures. Mineral oils tend to include wax impurities which coagulate at lower temperatures. A typical 10W-30 oil remains liquid at -50 °C (-58 °F)

Better high temperature performance. Synthetic oils have few low molecular weight hydrocarbons which evaporate at high temperatures.

Higher purity

Decreased oil consumption

Reduced friction and engine wear

Improved fuel consumption through better engine lubrication

Resistance to oil sludge problems

Crude oil doesn't have to be used for the production of the lubricants

Some synthetic motor oil producers offer extended intervals between oil changes (extended drain intervals)

Reduction of environmental impact (due to lower oil consumption)

 

 

Disadvantages

The primary disadvantage of synthetic oils is that they cost significantly more than mineral oils. Some manufacturers of synthetic oils, such as Amsoil and Mobil1, however offer extended drain intervals which allows for running the oil by over 7 times the length of conventional petroleum oils. This extended drain interval actually causes synthetics to be more cost effective over the course of 2 to 3 oil changes. However, with the recent rise in the price of petroleum the gap between the cost of a typical quart of petroleum motor oil and the typical quart of synthetic is almost negligible.

 

Anecdotally, synthetic oils can cause problems with older seals which are prone to leakage. As long as the vehicle or equipment in question is in sound mechanical condition then using synthetic oils should not be an issue.

 

Semi-synthetic oil

A semi-synthetic oil is a blend of mineral oil with no more than 30% synthetic oil. They are designed to provide many of the benefits of synthetic oil without matching the cost of pure synthetic oil. MOTUL introduced the first semi-synthetic motor oil in 1966

The cost of using good fully synthetic oil and changing every 3000 miles is really little compared to how it keeps the engine running fine and the cost of fuel.

Its like tyres and other things, dont cut corners with maintenance on a zed as it costs more in the long run when it goes wrong.

I don't know if 'Oilman' is around, but I would love to hear what he says about the theory that MORE wear is caused by changing the good quality fully synthetic oil every 3000 miles than leaving it for 10000 miles or more!! As it seems to imply in the report/tests on the link provided above!

Can't really see it myself!

I don't know if 'Oilman' is around, but I would love to hear what he says about the theory that MORE wear is caused by changing the good quality fully synthetic oil every 3000 miles than leaving it for 10000 miles or more!! As it seems to imply in the report/tests on the link provided above!

Can't really see it myself!

:confused: :confused: :confused:

 

 

 

"This extended drain interval actually causes synthetics to be more cost effective over the course of 2 to 3 oil changes "

:confused: :confused: :confused:

 

 

 

"This extended drain interval actually causes synthetics to be more cost effective over the course of 2 to 3 oil changes "

 

If you look at the link included in a post above, it actually says that it causes more wear to your engine doing 3000 mile changes than 10000 mile changes!! They say that the oil becomes BETTER with age!! Up to about a 10000 mile interval. I find this hard to believe, but that is what they claim from their tests on synthetic oils, they say that Ford and others have tested and come to this conclusion also!

This is the link:

http://neptune.spacebears.com/cars/stories/mobil1.html

10/40 semi synth any brand :D

 

NOT Magnatec or Fully synth

go with chunk on this one.dont rate synthetic oils for zeds.for more modern engines yes but on older cars or cars with higher mileage it usually just causes smoke problems are weeps past seals.

castrol rs 10-60 or millers 10-60 fully synthetic

 

there will always be debates about oil, but iv always used the above and personally found it to be the best, as has many people on here.

I hate rs10/60 its crap.

How on earth can 2 traders have opposite opinions over an oil? I mean Its either good or bad right? one of you must be wrong?

Castrol RS 10/60 for me the rest is crap :rofl:

So whats the answer then? jury still out on this one

 

not such a bloody easy oil question after all then!

So whats the answer then? jury still out on this one

 

not such a bloody easy oil question after all then!

 

There is not an answer Carl.

 

People use what they feel is right for them and my choice is Castrol RS

Castrol RS 10/60 for me the rest is crap :rofl:

 

 

Think im inclined to agree with you there mac :) i,ve never had any probs with castrol in the past used it in the yanks and dragsters with no probs

It probably boils down to the condition of your engine then. Mine has only done some 99K (60Mile) and has been well looked after, hence a fully synthetic is not a problem. As seals age, a semi sythetic may be better - just a thought. As I said, I use fully synthetic with 10K (6K mile) changes and have no problems what so ever.

lol @ Paul (swz)

So what's your oil of choice??? :bow:

More to the point, what will you be putting in my Zed in the future????

Not crap i hope!

It probably boils down to the condition of your engine then. Mine has only done some 99K (60Mile) and has been well looked after, hence a fully synthetic is not a problem. As seals age, a semi sythetic may be better - just a thought. As I said, I use fully synthetic with 10K (6K mile) changes and have no problems what so ever.

 

As above, along with personal preference/experience and level of tune.

 

With a stock engine a "60" viscosity (as in 10w60) is unnecessary. NIssan specified 10w40 semi-synthetic; so to improve on that a 10w40 or 5w40 fully synthetic is a suitable upgrade.

 

I use Shell Helix Ultra 5w40 and have no problems at all. negligible oil consumption and "textbook" oil pressure when hot. That's on a stock 85k mile twin turbo.

 

Highly tuned engines will genrate more heat so the "40" bit will be too low. In those extremes (Like MAc1) a 10w60 is best choice - Like Greg said, Castrol or Millers are among the best available.

 

Richard :)

Why change engine oil every 3000 miles? The handbook says every 6000miles.

 

Why use 5W oil? It doesn't get that cold in the U.K.

 

Is there a different preference for TT and N/A? The handbook doesn't differentiate.

 

By the way, did you see the handbook that sold for £101.99 on eBay the other day? Mind you, it was post free. http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&rd=1&item=160020034386&ssPageName=STRK:MEWA:IT&ih=006

 

Dave

..................Why use 5W oil? It doesn't get that cold in the U.K...................Dave

 

True, but that is the grade most readily available synthetic oils seem to come in.......... :)

 

Check out the shelves in premium branded petrol stations, sure you also see the occasional 5w30 now but the "30" is too thin when hot for a 300zx.

 

Richard :smw:

The idea of a synthetic is that it does not need changing every 3000 miles because it stays in grade for longer. A decent synthetic will easily do 6000 miles and the best ones 9000-12000 miles that is why they cost more to start with.

 

The bigger question is are they required and the answer to this is a simple one:

 

NO - in a stock road car

YES - in a modded or track car

 

The benefits of synthetics are many as they are superior lubricants but to put down some facts and at the risk of being boring those that are not interested need not read on as this is long.

 

The basic benefits are as follows:

 

Extended oil drain periods

Better wear protection and therefore extended engine life

Most synthetics give better MPG

They flow better when cold and are more thermally stable when hot

Esters are surface-active meaning a thin layer of oil on the surfaces at all times

 

If you want to know the reasons why then please read on but, warning - Long Post!

 

Stable Basestocks

 

Synthetic oils are designed from pure, uniform synthetic basestocks, they contain no contaminants or unstable molecules which are prone to thermal and oxidative break down.

Because of their uniform molecular structure, synthetic lubricants operate with less internal and external friction than petroleum oils which have a non-uniform molecular structure.

The result is better heat control, and less heat means less stress to the lubricant.

 

Higher Percentage of Basestock

 

Synthetic oils contain a higher percentage of lubricant basestock than petroleum oils do.

This is because multi-viscosity oils need a great deal of pour point depressant and viscosity improvers to operate as a multigrade.

The basestocks actually do most of the lubricating. More basestocks mean a longer oil life.

 

Additives Used Up More Slowly

 

Petroleum basestocks are much more prone to oxidation than synthetic oils. Oxidation inhibitors are needed in greater quantities in petroleum oils as they are used up more quickly.

Synthetic oils do oxidize, but at a much slower rate therefore, oxidation inhibiting additives are used up more slowly.

 

Synthetic oils provide for better ring seal than petroleum oils do. This minimizes blow-by and reduces contamination by combustion by-products. As a result, corrosion inhibiting additives have less work to do and will last much longer in a synthetic oil.

 

Excellent Heat Tolerance

 

Synthetics are simply more tolerant to extreme heat than petroleum oils are. When heat builds up within an engine, petroleum oils quickly begin to burn off. They are more volatile. The lighter molecules within petroleum oils turn to gas and what's left are the large molecules that are harder to pump.

Synthetics have far more resistance as they are more thermally stable to begin with and can take higher temperatures for longer periods without losing viscosity.

 

Heat Reduction

 

One of the major factors affecting engine life is component wear and/or failure, which is often the result of high temperature operation. The uniformly smooth molecular structure of synthetic oils gives them a much lower coefficient friction (they slip more easily over one another causing less friction) than petroleum oils.

Less friction means less heat and heat is a major contributor to engine component wear and failure, synthetic oils significantly reduce these two detrimental effects.

Since each molecule in a synthetic oil is of uniform size, each is equally likely to touch a component surface at any given time, thus moving a certain amount of heat into the oil stream and away from the component. This makes synthetic oils far superior heat transfer agents than conventional petroleum oils.

 

Greater Film Strength

 

Petroleum motor oils have very low film strength in comparison to synthetics. The film strength of a lubricant refers to it's ability to maintain a film of lubricant between two objects when extreme pressure and heat are applied.

Synthetic oils will typically have a film strength of 5 to 10 times higher than petroleum oils of comparable viscosity.

Even though heavier weight oils typically have higher film strength than lighter weight oils, an sae 30 or 40 synthetic will typically have a higher film strength than an sae 50 or sae 60 petroleum oil.

 

A lighter grade synthetic can still maintain proper lubricity and reduce the chance of metal to metal contact. This means that you can use oils that provide far better fuel efficiency and cold weather protection without sacrificing engine protection under high temperature, high load conditions. Obviously, this is a big plus, because you can greatly reduce both cold temperature start-up wear and high temperature/high load engine wear using a low viscosity oil.

 

Engine Deposit Reduction

 

Petroleum oils tend to leave sludge, varnish and deposits behind after thermal and oxidative break down. They're better than they used to be, but it still occurs.

Deposit build-up leads to a significant reduction in engine performance and engine life as well as increasing the chance of costly repairs.

Synthetic oils have far superior thermal and oxidative stability and they leave engines virtually varnish, deposit and sludge-free.

 

Better Cold Temperature Fluidity

 

Synthetic oils do not contain the paraffins or other waxes which dramatically thicken petroleum oils during cold weather. As a result, they tend to flow much better during cold temperature starts and begin lubricating an engine almost immediately. This leads to significant engine wear reduction, and, therefore, longer engine life.

 

Improved Fuel Economy

 

Because of their uniform molecular structure, synthetic oils are tremendous friction reducers. Less friction leads to increased fuel economy and improved engine performance.

This means that more energy released from the combustion process can be transferred directly to the wheels due to the lower friction. Acceleration is more responsive and more powerful, using less fuel in the process.

 

In a petroleum oil, lighter molecules tend to boil off easily, leaving behind much heavier molecules which are difficult to pump. The engine loses more energy pumping these heavy molecules than if it were pumping lighter ones.

Since synthetic oils have more uniform molecules, fewer of these molecules tend to boil off and when they do, the molecules which are left are of the same size and pumpability is not affected.

 

Synthetics are better and in many ways, they are basically better by design as they are created by chemists in laboratories for a specific purpose.

 

Cheers

Simon