Changing oil at 7500km

[MrGadget]

Yes, this is another post about engine oil for the GTI, sorry.

I have read lots of posts about this but still confused.

Seems like the most common oil people are buying are the Castrol Edge Sport 0W-40, Castrol Edge Sport 5W-30 and Mobil 1 0W-40.


I will be doing oil changes every 7500 (or 6 months) so does any of these oils make a difference?

Is there a good webisite that explains what these numbers actually mean?

Thanks.

[Maverick]

Find an oil that you're happy with (brand/type) but if you're getting the dealer to perform the yearly changes you're best of using the same oil if possible.

Make sure the oil is VW approved, here's a list of all the oils that are approved for use, there are two standards that can be used with the GTI in Australia and the newer one is the 504.00/507.00.

EDIT: Some of the oils listed for the 502.00 standard (the older one) are semi synthetic whereas all the oils in the 504.00/507.00 are full synthetic, just something to watch for when purchasing the oil.

[Jase]

Gadget, those numbers you've mentioned relate to the nature of multigrade oils which have varying viscosity at different temperatures. For instance the 5W (W = winter) indicates how the oil would behave when cold, while the 40 is how it acts when hot. The oil acts like a thin oil when cold so that they can circulate through the engine quickly on start up, and like a thicker oil when hot, to provide the necessary engine protection.

As Mav has mentioned, the main importance is to simply ensure the oil meets VW standards (i.e. VW 504.00/507.00) and select the brand that you like / trust. Viscosities aren't really important as you're bound around 5W-30 in most cases.

[stephen8512]

is there much difference between full synthetic and semi synthetic? wats the difference and which is better?

[Maverick]

is there much difference between full synthetic and semi synthetic? wats the difference and which is better?

From: http://en.wikipedia.org/wiki/Synthetic_oil

Synthetic oil

Synthetic oil consists of chemical compounds which were artificially made (synthesized) from other compounds (versus from crude oil/petroleum). As with petroleum oils, uses of synthetic oil products include food oils, fuel, and lubrication; particularly because of a shortage or expense of petroleum.[citation needed].
When synthetic oil is used as a substitute for lubricant refined from petroleum, it generally provides superior mechanical and chemical properties than those found in traditional mineral oils.

Advantages
The technical advantages of synthetic motor oils include:[citation needed]
Measurably better low and high temperature viscosity performance
Better chemical & shear stability
Decreased evaporative loss
Resistance to oxidation, thermal breakdown and oil sludge problems
Extended drain intervals with the environmental benefit of less oil waste.
Improved fuel economy in certain engine configurations.
Better lubrication on cold starts

Disadvantages
The disadvantages of synthetic motor oils include
Initial costs are usually two to four times greater than petroleum-based oils, though at one time, man-made oils cost ten times more than petroleum[citation needed]. Initial costs are often mitigated by extended change intervals, which individuals may confirm through used oil analysis (UOA).
The lower friction may make them unsuitable for break-in (i.e. the initial run-in period of the vehicle) where friction is desirable to cause wear. Improved engine part machining has made break-in less critical than it once was though. Many modern cars now come with synthetic oil as a factory fill.
Potential decomposition problems in certain chemical environments (industrial use dominantly)
Potential stress cracking of plastic components like POM (polyoxymethylene) in the presence of PAOs (polyalphaolefins).
Potential on some older pushrod race engines with roller lifters for the roller itself not to spin with camshaft movement, but rather slide while the roller itself remains either stationary or at a lower circumferential speed than that of the camshaft lobe.[citation needed]
Synthetics do not hold lead in suspension as well as mineral oil, thus caution is advised when the engine is run on leaded fuel.[citation needed] As an example, leaded fuel is still commonly used in aviation (avgas).[11]
In July 1996, Consumer Reports published the results of a two year motor oil test involving a fleet of 75 New York taxi cabs and found no noticeable advantage of synthetic oil over regular oil.[12] In their article, they noted that "Big-city cabs don't see many cold start-ups or long periods of high speed driving in extreme heat. But our test results relate to the most common type of severe service — stop-and-go city driving." According to their study, synthetic oil is "worth considering for extreme driving conditions: high ambient temperatures and high engine load, or very cold temperatures." [13] This research was criticized by some because most engine damage appears to be caused by cold starts, and their research method may not have included enough cold starts to be representative of personal vehicle use.[14]
Synthetic oils are not recommended in automotive rotary engines.[15]

Semi-synthetic oil
Semi-synthetic oils (also called 'synthetic blends') are blends of mineral oil with no more than 30% synthetic oil. Designed to have 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.[16]
Lubricants which have synthetic base stocks even lower 30%, high performance additive packs consisting of esters can also be considered as synthetic lubricants. Ratio of the synthetic base stock is generally used to define commodity codes among the customs declarations of tax purposes.

[blackmagic]

Find an oil that you're happy with (brand/type) but if you're getting the dealer to perform the yearly changes you're best of using the same oil if possible.

Make sure the oil is VW approved, here's a list of all the oils that are approved for use, there are two standards that can be used with the GTI in Australia and the newer one is the 504.00/507.00.

EDIT: Some of the oils listed for the 502.00 standard (the older one) are semi synthetic whereas all the oils in the 504.00/507.00 are full synthetic, just something to watch for when purchasing the oil.

I may be wrong but list states that Castrol Edge 5-30 is right oil........but according to Castrol Australia web-site only 0-40 Edge is approved ???

[brad]

is there much difference between full synthetic and semi synthetic? wats the difference and which is better?

I don't like semi-synthetic/synthetic blends because you have no way of knowing the ratio of synthetic to mineral oil. Is it 5:95 or 50:50 or 95:5?

I may be wrong but list states that Castrol Edge 5-30 is right oil........but according to Castrol Australia web-site only 0-40 Edge is approved ???

Edge 5w-30 is VW502.00 which is suitable for 15,000km service intervals.
Edge 0w-40 is VW505.00 which is the longlife spec.

I've used Edge 5w-30 in preference to other oils on my last 3 cars simply because when it's on special at Supercheap for $29.95 it's the best bang-for-buck synthetic oil you can buy.

It hasn't been that price for ages so at my next oil change I'll probably switch to Fuchs or Mobil1 as I think they are slightly better oils.

Oil choice is very subjective once you met the required spec. I don't like Motul (tried it twice in my Liberty & it lost viscosity very quickly) but plenty swear by it. Pennzoil synthetics (not Pennrite) are also pretty lousy IMO.

If you are doing 7500km oil changes then it might also be worth your while to change viscosities as the ambient temperature changes.

How many km do you intend to keep the car? I used to do half-changes on my previous cars but I think the only people that benefited were the oil manufacturers & the next owner of the vehicle.

[NickZ]

If you are keeping your car for less than 4-5 years (especially if you are getting extended warranty), then I do not see any benefit in doing an oil change at 7500km unless you have 'severe driving conditions' (i.e. lots of short trips, etc).

If you like to keep your car for longer than this, then IMO there is benefits to changing your oil. The 15000km service interval is a compromise between the car having lower servicing costs under a typical lease of 3-5 years (which makes the car more financially attractive when calculating estimated lease costs), whilst not compromising the engine.

The 7500km oil change, IMO, will leave your engine in a lot better condition after 8-10 years compared to sticking with the 15000km intervals. I am no expert, but this has been my experience based on older cars I have driven (and maintained), and other more 'wiser' heads.