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Flipper Dog
22-02-2008, 08:48 PM
I found the following information on another post and thought this may be of interest to others out there.
Thanks to Guy at MyTreg.com for this.

10w-40, What does it mean??

We have answered thousands of oil questions in the last 4 years but the most frequently asked one is “What do the numbers mean?”

In short, if you see an expression such as 10W-40, the oil is a multigrade which simply means that the oil falls into 2 viscosity grades, in this case 10W and 40.

This is made possible by the inclusion of a polymer, a component which slows down the rate of thinning as the oil warms up and slows down the rate of thickening as the oil cools down.

Multigrades were first developed some 50 years ago to avoid the routine of using a thinner oil in winter and a thicker oil in summer.

For a 10w-40 to attain the specification target a 10W (W = Winter please note!) the oil must have a certain maximum viscosity at low temperature. The actual viscosity and the temperature vary with the viscosity grade but in all cases the lower the number, the thinner the oil. For example a 5W oil is thinner than a 10W oil at temperatures encountered in UK winter conditions.

This is important because a thinner oil will circulate faster on cold start, affording better engine protection and therefore lower long term wear!

For a 10w-40 to attain the other specification target a “40” oil must fall within certain limits at 100 degC. In this case the temperature target does not vary with the viscosity grade, if there is no "W" the measuring temperature is always 100degC.
Again the lower the number the thinner the oil, a “30” oil is thinner than a “40” oil at 100 degC, which is typical of maximum bulk oil temperatures in an operating engine.

Engine makers are, of course, very well aware of this and specify oils according to engine design features, oil pump capacities, manufacturing tolerances, ambient temperature conditions etc. It is important to follow these guidelines, they are important and are stipulated for good reasons.

Finally, if the engine has been modified or is used in stressed conditions, the operating conditions may well be outside the original design envelope. The stress on the oil caused by increased maximum revs, power output and temperature may require that an oil of a different type and viscosity grade would be required.

These examples show viscosities at different temperatures:

Grade................0degC............10degC...... .........40degC...............100degC

0w-40...............665cst.............354cst........ ..........82cst................14cst
5w-40...............842cst............ 430cst..................91cst................14cst
10w-40.............874cst.............440cst .................91cst................14cst
15w-40...........1260cst.............595cst........... ......107cst................14cst

In a nutshell, that’s what a multigrade is all about!

Guy.

gregozedobe
22-02-2008, 10:35 PM
Thanks for that, unfortunately VW's engineers have gone a looong way from simple 5w-50w type specifications ! Now you need to know the exact VW-specific oil which your TDI engine MUST have, such as 506.01, 507.00 etc, and woe betide you if you get it wrong :( Heaven forbid that you put a non-DPF oil in a DPF equipped engine (well according to VW, anyway.

Actually, for nearly all modern VW TDIs you can just use a VW 507.00 engine oil (IIRC), with the R5 pre-DPF engine being the exception (506.01 is the go for these). But you should really look at your owner's manual to see what it says to use. Just don't expect to find the right oil in the motoring section of your nearest K-Mart or Big W.

phaeton
23-02-2008, 07:25 AM
What about the other Letters ;)

API = American Petroleum Institute

and SG/CD.........see here http://www.carbibles.com/engineoil_bible.html

Transporter
25-03-2008, 08:35 PM
API or SAE it doesn't really matter since these standards are voluntary only and oils tested to only API or SAE standards doesn't guarantee that they are approved by the engine manufacturer. Some oils have API and SAE marking on the label as well as engine manufacturer approval such as VW 506.01, MB sheet no.229.3 and so on.
API or SAE doesn't test oils, oils are tested by oil manufacturers using API or SAE testing methods and API and SAE recommend that oil manufacturers keep the results of the tests.
Some engine oil tests last 50 hours VW test for 506.01 approval is 1000 hours more in this article.

http://www.bp.com/liveassets/bp_internet/globalbp/STAGING/global_assets/downloads/F/Frontiers_magazine_issue_3_Keep_on_running.pdf

Enjoy the reading.
P.S.
if it doesn't have VW 505.01, VW506.01 or VW 507.00 approval it wasn't properly tested and the unit injector pd engine will not last.

gregozedobe
26-03-2008, 06:27 AM
P.S.
if it doesn't have VW 506.01 approval it wasn't properly tested and the unit injector pd engine will not last.

Nevertheless, I will continue to put VW 507.00 engine oil into my 2007 2.5 TDI Transporter (mit DPF), as that is what VW recommend ;)

Transporter
26-03-2008, 07:55 PM
Nevertheless, I will continue to put VW 507.00 engine oil into my 2007 2.5 TDI Transporter (mit DPF), as that is what VW recommend ;)

I didn't mean that you have to use 506.01 in your T5 which has particle filter.
You should always use oil recommended in your manual.
I will correct my previos post.:)
Mate, how is your T5 running after that coolant contamination with oil. Did you get all hoses in cooling system replaced? (Oil attacks rubber and hoses could fail)

gregozedobe
27-03-2008, 06:44 PM
Mate, how is your T5 running after that coolant contamination with oil. Did you get all hoses in cooling system replaced? (Oil attacks rubber and hoses could fail)

My T5 is running well, but it was running well even when there was a whole lot of oil in the coolant and the MFD was madly displaying all sorts of messages about impending doom :)

There is a small amount of oil in the coolant bottle still, but it is booked in to the dealers have that cleaned out soon. I recently drove from Canberra to Adelaide and back, and no more oil appeared, so hopefully I have finally got it all out of the engine. I'm told that the dealer has actually been flushing the coolant system with the VW coolant flush, but all I can say is that seeing as it took about 16 flushes to get it all, it must be remarkably ineffective !

Interesting point about oil attacking the rubber coolant hoses. I might insist on either a written assurance from VWA that neither the oil nor the flushing agent will have done any damage to these hoses; or replacement of said hoses if they can't give me that assurance.

In any event, I have decided to buy the extended VWA warranty for the extra two years, so I will have factory coverage for a total of 5 years. If I've still got my T5 then I would probably schedule replacement of all coolant hoses anyway (I do that with all my vehicles as preventitive maintenance, and since doing that I've had no problems with radiator hoses etc.).