switching to synthetic oils

Steve

I would have to say that yes it does leak, there is oil below the cylinder head joint and the sump is always damp with oil. but according to the dipstic it cannot be leaking much at all.

OK, I had in my mind that the only thing that matters is the viscosity.

I am having to drive to yorkshire on thursday so I'll change the oil before that which means I'm going to buy some tomorrow. I shall seek out some 15w40 and check for API as you quoted there.

Regards. Mark.(AKA, Mr.Nice.)

There is no such absolute rating for all vehicles. FWIW I feel that for a LR engine of his age and tolerance, 20w/50 would be no problem in sub zero temperatures as long as it was fairly fresh in the sump. The soot load of this particular engine, causing the oil to thicken as the load increased, would probably cause a problem for lesser performance oils such as a 'CC', possibly resulting in engine failure if the oil had more than half the 6000 mile interval on it. This is not absolute.

Again FWIW, I have a brand spanking new LR product with the state of the art diesel. In the book of Words it states on page 261, and I quote :-

5w/40 will protect from -30C to 50C

10w/40 will protect from -10C to 50C

Now the implication of this is that you are obviously wrong when you say a

I would like to know however, where you get your figures for the absolute change in temperature protection for those two viscosities from. On what basis do you imagine they have changed considering that the SAE viscosity rating scales have not changed for a very long time and that therefore a

Huw

I kind of thought you did. It is very important for you to realise that the viscosity is only secondary to the performance requirement.

API stands for the American Petroleum institute and you are looking for CH4 or CI4. Other equivelent standards which you should seek on the can are ACEA E3 and mb228.3

Any one of these on the can means you can be confident that the oil is designed for heavy duty work in diesel engines with a high oil soot load. The best long drain oils you can get, which means that your LR is really as well protected as it can be with any oil, mineral or synthetic.

Huw

Your definition is based before my time I suspect. I apologise for not recognising it.

...because I am the designer of one of the two equipments that test the oils to GIVE it the designation 20W ?

Hopefully I should have picked up one or two pointers by now.

I am a member of ASTM and sit on the ASTM D02.07 committee designated to look after viscometric testing of engine lubricants, and I sit there with friends who helped SET SAE J300 , which made mandatory changes to CCS limits in Feb 2001. Causes no end of fun for everyone.

I have seen customers go white when they realise they have been shipping stuff to the old specs for the last three years....

Anyway, there was a very large engine test series done to reestablish the background for the cold-crank limits in the late 1990's - this is largely down to advances in engine designs since the 1950's which is when the original data was developed.

Would you like me to send you the viscometric data ?

Steve

Ing. Steve Taylor

Technical Director Ravenfield Designs Ltd.

AFAICS you are quoting the ability or the standard for cold cranking performance as a suitability for an application. In practice it is most important, more important in practice, that an oil is able to protect the engine from a cold start for the first ten minutes to quarter of an hour when the oil is still extremely cold. This will require a lighter viscosity than one that just allows the engine to fire, hence the difference between your suitability figures and practical ones as described by Land Rover and most other engine manufacturers, for whom the cold cranking performance is little more than accademic interest.

No thank you because you are concerned with an academic figure and measurement for cold cranking performance. This is of very limited use for the practical user of the end product who risks ruining an engine if he uses cold crank limits as an indicator of protection and suitability in his vehicle engine. Notwithstanding your vocation, I beg to differ, if only by a small amount, as does Land Rover and BMW. In fact I have never known anyone to advise use of a 15w/* mineral oil below occasional -10 in practice although you are perfectly correct in that it will crank and run, all other things allowing.

Even Finland's premier engine manufacturer, Sisu Diesel, advise SAE J300D viscosity

10w/30 from -20 to 25C

15w/30 from -10 to 30

Again these may not be exactly the same as advised by other manufacturers and it reflects the expected duty and design of the application.

These LR and Sisu figures are practical guides provided by manufacturers and not *minimum cold cranking figures*, which again I have to say are not really relevant to the user of the engine. Why you should use these figures is probably a result of your vocation but they are not realistic in practice for someone who wishes adequate protection after the engine has fired and before the oil has warmed significantly. The engine manufacturer knows what viscosity will provide the running protection it requires for its engines and should not really be second guessed by anyone who perhaps understands the oil viscosity standards and their measurement in the lab backwards but, I venture to suggest, perhaps uses the standards he is acquainted with in an inappropriate way in this practical instance.

But then again, what the heck do I know? This is Usenet LOL

Huw

Very interesting, all this about oil.

My wifes Defender 90 (built 1990, 2.5 TD engine, 110 000 km) will have to get new oil about next month...what should we use? What is recommended by LR? We still were not able to even get an owners manual with some basic information what the landy needs :(

regards - Ralph

As explained in previous correspondence, API CH4 or equivalent with a viscosity appropriate to where you are. Simple.

Huw

I eded up using Millers Oils XMD

Regards. Mark.(AKA, Mr.Nice.)

Great stuff . I generally buy in 205litre packs and at present the Fuchs equivalent is selling retail for £155+VAT [89ppl inclusive] so I think the Millers is a bit expensive but that is partly a function of pack size I guess.

Huw

I don't have anywhere to store in quantity, I'm happy to pay that price though for 5 litre bottles. I'll probably use some of theirs for the wifes saab too.

Regards. Mark.(AKA, Mr.Nice.)