FAQ: What engine oil should I use?

[Removed]

Engine oil ratings are included in the owner?s manual.

 

Reputable sources also vary with some saying use synthetic and some saying mineral is fine (Nissan only specifically recommend mineral oil apparently because this is the only oil they tested during the 350?s development rather than because they feel there is a problem with synthetic).

 

Some say that if you do intend to change to synthetic oil, you should wait until, say the 9000 mile service as this will help the engine to bed it better.

 

I personally swapped to Motul 300V 5W30 (fully Synthetic) at my P2 service and the car seems to like it a lot.

[Guest prescience]

Specification information on 2 highly-recommended (for the Z) manufacturers as identified by oilman (Simon)

 

http://www.opieoils.co.uk/performance_l ... motul.aspx

 

http://www.opieoils.co.uk/performance_l ... olene.aspx

[Guest prescience]

350Z Fluids Recommendation Data

 

I've been reading a few oil threads here and thought this data may be of use. It comes from a proprietory database to which I subscribe and the data contained in it comes from OEM's.

 

Nissan, 350 Z, 350 Z / Fairlady Z, 2004- [Preliminary Info]

Manufacturer: Nissan Motors Co., Ltd., Tokyo, Japan

Drive type: r.w.d.

Cylinder capacity: 3498 cc

Power output: 280 HP/206 kW at 6200 RPM

 

Engine VQ35DE

Petrol, 4-stroke, 6 cylinder, V, 4 valves/cil., liquid cooled

Cylinder capacity: 3498 cc

Power output: 280 HP /206 kW at 6200 RPM

Capacity:

4.7 liter

Overhaul capacity: 5.4 liter

Filter capacity: 0.3 liter

Use: normal - OEM recommendation

Below 15 API: SL SAE 5W-30

Above -20 API:SL SAE 5W-40

Above -20 API: SL SAE 10W-30

Above -20 API: SL SAE 10W-40

Above -20 API: SL SAE 15W-40

Below 15 ILSAC GF-2 SAE 5W-30

Above -20 ILSAC GF-2 SAE 5W-40

Above -20 ILSAC GF-2 SAE 10W-30

Above -20 ILSAC GF-2 SAE 10W-40

Above -20 ILSAC GF-2 SAE 15W-40

.....

 

Transmission, manual, 6 speed

Manual

Capacity: 2.9 liter

Gears forward: 6

Gears reverse: 1

Use: normal - OEM recommendation

year-round API: GL-4 SAE 75W-85

.....

 

Differential, front, limited slip

Capacity: 1.4 liter

Use: normal - OEM recommendation

year-round API: GL-5 LS SAE 80W-90

 

Use only limited slip hypoid gear oil which is approved for Nissan LSD.

.....

 

Transmission, automatic

Automatic

Gears forward: 5

Gears reverse: 1

Use: normal - OEM recommendation

year-round Special ATF, Nissan -

 

OEM recommends Nissan Matic J ATF.

.....

 

Hydraulic brakes/clutch system, ABS

Use: normal - OEM recommendationyear-round Brake fluid, DOT 3 -

year-round Brake Fluid DOT 4+ -

Never mix different types of fluids.

.....

 

Power steering

Capacity: 1 liter

Use: normal - OEM recommendation

year-round Dexron III -

.....

 

Grease points/nipples

Use: normal - OEM recommendation

year-round Lithium base multipurpose grease NLGI No. 2

.....

 

 

Cooling system

Capacity:

7.9 liter

Reservoir: 0.8 liter

Use: normal - OEM recommendation

year-round Nissan Anti Freeze Coolant (L250) -

.....

 

Hope this helps

 

Cheers

Simon

[Guest prescience]

Are Synthetic Oils Really Better

 

I thought this would be of interest as It's probably the question I get asked the most. Shame the answer isn't simple though!

 

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

[Guest prescience]

Why Oils Lose Viscisity With Use

 

Why do oils lose viscosity with use?

 

Viscosity Index Improvers.

An oils viscosity will decrease as the engine temperature rises. Viscosity Index Improvers are added to reduce this thinning. They are a key addative in the production of multigrade oils.

 

VI Improvers are heat sensitive long chain, high molecular weight polymers that minimise the viscosity loss of the oil at high temperatures. They work like springs, coiled at low temperatures and uncoiling at high temperatures. This makes the molecules larger (at high temps) which increases internal resistance within the thinning oil. They in effect "fight back" against the viscosity loss in the oil.

 

"Shearing"

The long chain molecules in VI Improvers are prone to "shearing" with use which reduces their ability to prevent the oil from losing viscosity. This "shearing" occurs when shear stress ruptures the long chain molecules and converts them to shorter, lower weight molecules. The shorter, lower weight molecules offer less resistance to flow and their ability to maintain viscosity is reduced.

 

This shearing not only reduces the viscosity of the oil but can cause piston ring sticking (due to deposits), increased oil consumption and increased engine wear.

 

Like basestock quality, VI Improvers also vary in quality. As with many items the more you pay, the better the finished article and more expensive, usually synthetic oils are likely to incorporate better VI improvers. All other things being equal the less VI improver an oil contains, the better it will stay in grade by resisting viscosity loss.

 

Which oils require more VI Improvers?

There are two scenarios where large amounts of these polymers are required as a rule.

 

Firstly in "wide viscosity span" multigrades. By this I mean that the difference between the lower "W" number and the higher number is large for example 5w-50 (diff 45) and 10w-60 (diff 50) are what is termed as "wide viscosity span" oils.

 

Narrow viscosity oils like 0w-30 (diff 30) or 5w-40 (diff 35) require far less VI Improvers and therefore are less prone to "shearing".

 

Secondly, mineral and hydrocracked (petroleum synthetic oils) require

more VI Improvers than proper PAO/Ester (Group IV or V) synthetic oils

as they have a higher inherent VI to begin with, this is due to

differences in the molecular straucture of the synthetic base oils

compared to mineral oils

 

It is a fact that many synthetics require significantly less VI Improver to work as a multigrade and are therefore less prone to viscosty loss by shearing.

 

Cheers

Simon

[Guest prescience]

Oils - You Get What You Pay For

 

A word of caution – You get what you pay for!

 

Below is an article written by John Rowland, Silkolene/Fuchs Chief R & D Chemist for 40 years.

 

Quote:

 

Costs of synthetics vary considerably. The most expensive are the “Esterâ€

[Guest prescience]

Oil - Cold Weather Selection

 

In this cold weather, it is beneficial to use an oil that has good cold start flow properties as it will get to the parts of the engine that need it far more quickly.

 

The "w" number which means winter is the key here and the lower the better.

 

It may seem odd but a 15w or 20w will struggle to get around the engine in very cold temps and I would strongly recommend a 10w or better still a 5w for better cold start performance.

 

90% of all engine wear occurs on cold start because the oil get thicker the colder it is which causes engine wear.

 

These numbers explain what I mean and bear in mind that the oil will be the following thickness at 100degC (sae 40 = 14cst, sae 50 = 18cst and sae 60 = 24cst)

 

At 0degC these are the numbers (thick!)

 

Grade.................At 0C.........At 10C...........At 100C

 

0W/20.............328.6cSt......180.8cSt..........9cSt

 

5W/40.............811.4cSt......421.4cSt..........14cSt

 

10W/50............1039cSt.......538.9cSt..........18cSt

 

15W/50.............1376cSt.......674.7cSt.........18cSt

 

20W/50.............2305cSt.......1015cSt..........18cSt

 

If you are using anything more than a 10w oil, always warm the car properly before driving it as the oil needs time to circulate.

 

Just a word of warning really.

 

Cheers

Simon

[Guest prescience]

Synthetic Oil Myths

 

I read so much stuff on the internet about Synthetic Oils that is simply not true so I felt it was time to tell the truth rather than accept the myth.

 

So in future when you see someone state any of these, please do me a favour and point them at this thread!

 

Synthetic motor oils damage seals:

Complete Nonsense! Any oil seals made after 1975 or thereabouts will be entirely compatible with any type of synthetic engine oil. (The same goes for synthetic gear oils and transmission oil seals.) It must be understood that everything associated with lubrication is thoroughly tested. The major oil manufacturers do not make oils that attack seals; seal manufacturers ensure that their products function correctly with modern lubricants.

 

Synthetic oils are too thin:

It is true that the best synthetic blends can be low viscosity (0w-20 for example), but they do not have to be! It is also true that the latest engines are designed to run on thin oil, which improves power output and fuel consumption. Even so, thicker synthetic based grades (10w-50, 15w-50, 20w-50etc) are available for air-cooled motors, older engines, or severe high temperature conditions. These grades can also benefit rebuilt classic engines dating back to the 1940s.

 

Synthetics mean higher oil usage:

The complete opposite of the truth. Oil consumption in well-maintained modern engines is mainly down to the oil evaporating at high temperatures. Synthetic base oils (specially the PAO and ester types) are very resistant to evaporation loss even in low viscosity blends, so oil consumption is minimised. Obviously, engines with worn valve guides, defective seals and worn piston rings will use oil regardless, so there is no point in using expensive synthetics as an ‘old banger lube’.

 

Synthetic oils are not compatible with other oils:

All engine oils intended for normal road use in recent 4-stroke engines are compatible with one another, regardless of the base make-up. (mineral, PAO/ester/hydrocracked synthetic, and semi-synthetic.) There is no need to flush or strip down an engine when changing from one type to another. (…but be careful with the exception: castor oil based racing oils.)

 

Synthetic oils produce sludge:

Well honestly, this is just totally daft. All synthetic bases are more resistant to oxidation than mineral oil, and sludge is largely due to oxidation. In any case, all motor oils intended for road use meet the higher API specs such as SH, SJ, SL and diesel equivalents. One of the main reasons for introducing the API specs back in the 1950s was to deal with oil sludge problems. All high-spec oils run very clean, especially synthetics.

 

Synthetic oils cannot be used with catalytic converters:

‘Cats’ will perform more efficiently and last longer if synthetic based engine oil is used. Their lower volatility (see 3 above) means that less oil reaches the combustion chambers via crankcase ventilation, so there are less harmful ash residues from burnt oil to de-activate the catalyst matrix.

 

Synthetic oils can void warranties:

People who make statements such as this never define the type of synthetic, thus revealing their ignorance. Provided that an oil meets or exceeds the API and viscosity ranges specified in the handbook, the warranty will not be affected. (By law, OEMs cannot insist that a particular brand of oil must be used to maintain warranty.)

 

Synthetic oils will last forever:

The better synthetic blends will certainly last longer*, especially in high performance or high annual mileage situations, but ‘forever’ is not on, simply because contaminants such as soot, and acid gasses from traces of sulphur in the fuel degrade the oil.

(*Provided that a very shear resistant VI improver polymer is used in the oil formulation to keep the viscosity up to spec. This point is often forgotten.

 

Synthetic oils are too expensive:

True, for older vehicles that use a lot of oil or are almost ready for the scrap yard. For cars that are worth maintaining, the right types of synthetic oil are a cost-effective way of retaining ‘as new’ performance, low fuel consumption, and reducing maintenance costs. (See 6 above, for example. ‘Cats’ aren’t cheap!)

 

Cheers

Simon

[Guest prescience]

Oil Labelling

 

see here ........

http://www.350z-uk.com/forum/viewtopic.php?t=2569