Engine Oils Synthetic

Besuide the quality of the oil which will include a high zinc content, the big thing that decides the number of K's between oil changes is the fuel burn and cold running. If your vehicle is working hard your recommended oil change period will be halved.

Contaminates in the oil are the big killers. Carbon, acid, water, silica and so on. So the oil maybe fine but your engine is being damaged by all the contaminates.

If you have the right filtration system which would include a centrifuge, a water boil of system and regular oil analysis you may not have to change your oil for many more kilometres than 80000K.

Just use the recommended grade oil and spec for your engine and take into account the ambient temperature range where you travel. Just buy from a mainstream oil company.

HI
You have just discovered the ""Australia Tax"" Mark up by retailers starting at 100-200% easy . Amsoil is no exception..
Use mobil 1 , ring there hot line for recommendation
Last time I purchased was around 230$ for 20ltrs 10w/40
Mobil 1 in the Usa is around 5$ per litre THATS RETAIL
Use only Poa /ester synthetic oil . Donot use Castrol or "lesser "" types .

Amsoil has been around for years. Hundreds of thousands of vehicles running around America with it. Very popular with motorbike people also. All synthetics are dear. We get ripped off incredibly badly here in Oz. I use full synthetic Valvoline and pay about $60 for 5 litres. $40 when on special, once a year at supercheep. 10,000klm on synthetic is no problems, even with a little towing and off roading. Heavy duty use of your vehicle (often towing and lot of off roading and drop oil changes down to 7000klms. Oils are cheap insurance and are the lifeblood of your motor..

$210 for 10 litres is expensive. I have heard of but not used Amsoil.
Used Valvoline full synthetic in a petrol engine ONCE only. After 10,000km the oil looked very Sick and had little lubricity. It was the worse synthetic I have used.
Shell synthetic experience is similar.
Mobil 1 for petrol is good.

For diesel I now use Mobil 1 5W40 full synthetic. That allows the engine lube to be cleaner after 10,000km than a good quality diesel oil achieves after just 5,000km. Current run is now at 14,000km with the Mobil 1 Diesel synthetic and oil is still cleaner than previous Multigrade Mobil was at the 5,000km mark. Cost for the Mobil is around $146 for 10 litres. Since it lasts longer and stays cleaner which = less changes and filters, it costs no more than normal.

If you have to change any oil at 5,000km there is something drastically wrong with the oil and/or the engine.

With oil monitoring and good filtration, B doubles run Mobil 1 Diesel up to 50,000km. It is then cheaper than lesser grades of oil and less down time.
In a normal 4wd you wouldn't run a full synthetic diesel oil to 50,000km unless it was monitored because you wouldn't know the actual state of the oil after such a long period.

Amsoil claim of 50,000km is/maybe in the IDEAL situation category and should be taken with salt over left shoulder. They aren't going to replace your engine for you anyway so claims are claims. Not always true to everyone's situation.
.

I have always been told never to put synthetic oil in an engine that has mineral oils in it and the engine has done a few K's . We run synlthetics in one of our trucks but only from new.I think we pay about $1,800 for a 205 litre drum. That is a Mobil product. Also run it in my defender.
Lindsay

My recommendation is as some others have said: "Stick with the main stream brands". Personally I would not use Nulon, Fuchs, Valvoline, Penrite, Amsoil or Castrol. I am sure plenty will disagree with me because oil brand is a bit of a Holden or Ford argument. Everyone thinks what they use is the best, often without any technical evidence to back up their claims. The colour of the oil, its lubricity, etc. is all bull.... One of the technically accepted ways you can correctly analyse the condition of an oil is with an atomic absorption spectrophotometer that most oil analysis labs utilise. However, whilst these machines will analyse the oil for the chemical contaminants, the results of which if correctly interpreted can assist early detection and rectification of potential engine problems, they cannot check the quality of the 'additive package' or the lubricity of the oil. As far as the oil brands that are not 'main stream' goes, the majority of them use base stock from the majors anyway. If you don't believe me, take a look over the back fence of any major oil wholesale distributor and see what brands of oil are painted on the 205 litre packages. Alternatively do a Google search to see if you can find where their oil refineries are located if in fact they do exist.

Interesting to find that Mobil oils are not stocked by Repco or Supercheap.

Where do you get a good deal on Mobil oil?

bill

All the major brand diesel spec oils are designed to run in long drain applications.

What that means is they are made from good quality base oil stock and have a strong additive package that will go the distance.

HOWEVER, it is usually not the oil used that determines the change interval but the motor.

The modern big end top spec truck engines will run extraordinarily long drain intervals, because they are very well designed motors with big sumps and very good filtration systems ..... after all these trucks have engines that cost more than the entire vehicle most of us deal with.
If you are spending half a million bucks pluss for a top end prime mover you expect no less.

Remember there are trucks on the road that will do 2000Km per day, and the engine may not stop for more than 1/2 an hour for 3, 4 or 5 days at a time.
They just keep changing the drivers and keep the wheels rolling.
5000 and 10 000 Km oil changes just are not workable for these guys.

the reasons most of the small diesels have such short drain intervals (5000Km in most of the pre-common rail engines) is because they are not in the same league as the big end of town.

Most of the small pre-common rail diesels are dirty little things, soot passes the rings into the crank case with every engine stroke. Thus the oil gets loaded with soot and rapidly turns black ....... if run for extended periods the oil gets thick and the relatively small crude filter clogs ....... no matter what oil you use, in these motors you will not get 50 000 between oil changes without compromising your engine life.

the post common rail engines are mostly cleaner, but they still are not in the same league as the big truck engines some of which will run 100 000Km between changes with the right oil and management.

Now to the synthetic thing.
Worry more about the spec that the oil meets, more than it being synthetic or not.

even pretty much the entry level 15w40 diesel spec oils with need some synthetic content to achieve the spec's they are guaranteed to meet.

The diesel spec oil market is very very competitive, the big transport companies use oil in massive volumes ....... many of those transport companies have their own labs and engineers, particularly the bigger transport companies in the US.

Amsol is very well regarded in the US and mostly comes out right at the top of the rankings in the oil comparisons ....... but among oils of the same spec, there is very little separates them. If it was a horse race the top handfull would be seperated by a nostril and the also rans being less than half a length behind.

The three major oil companies Caltex, Shell and Mobil always come out in the top half a dozen ..... with BP and their Castrol and Valvoline brands dragging along behind with the minor brands.

There has been a bit of a shake up in the diesel oil market in the last year or so, with all the major brands bringing out new product or upgrading their formulars.

Even Castrol RXsuper finally has a JASO DH1 rating.

All of the major oil companies now have top spec synthetic diesel spec oils.

I've been using Caltex Dello400 ( a Jaso DH1 rated oil) for quite a few years now, there has been is Delo LE ( the DH2 product) for years, ( both will have some synthetic component) but there is now as declared synthetic blend and a full synthetic in the Dello range.

Similar applies to all the other major brands and ranges.

I don't believe there is any good reason to pay excessivley for an imported boutique oil ....... apples for apples, there is not much seperates oils that meet the same specs.

SO, buy your oil where the truckies shop, either a diesel spares shop, a company fuel depot or a truck stop that stocks oil.

Buy by the 20 at least and shop it well

I buy my delo 400 from a nearby Caltex depot and last 2 drums cost me about $120 inc GST.

Pick brand ...... any of the top 3 will be fine ....... Castrol if you must.

But look at the spec's that the oils meet and look further than the API ratings ...... both JASO and ACEA oil specs are more specific and more stringent.

Avoid paying for the retail branded and packaged products, the commercial diesel spec product will pretty much always out spec the retail version and be cheaper by far in a 20.

cheers

HI
The other major item effecting service interval is sump capacity .
U see this in industry all the time eg the engine is a stationary motor 10lt sump .
Fit this to equipment and the sump capacity shrinks to 5-7 ltrs and the service interval shrinks as well.