Synthetic Oils - Which are and which aren't?!

Hi

Millers Oils do various fully synth oils. I used some wide range synth gear oil of theirs once on a slightly knackered Maestro gearbox (honda box). The oil was supposed to vary viscosity less over temperate ranges than mineral oil.

It seemed pretty good, in that the box was OK hot and cold. Not a totally fair comparison as the crap that was in there originally:

a) Came out like water after I heated the box to drain it (by driving);

b) Turned into treacle at 5C, to the point that one could invert a jam jar full of the stuff without it falling out.

Any *new* oil would have helped but Millers gave me no complaints. Prior to change, gear change was very difficult at 5C, turning into sloppy+crunchy when hot. Can't remember the exact product, this was 12+ years ago...

HTH

Tim

The definitive answer is that it matters not a hoot. What matters is which official International and individual car brand performance Standard is met by an oil. All other matters are secondary. Look for API and ACEA standards plus whatever manufacturers standards your oil has to meet. They are printed on the can.

Huw

I don't know the answer. What is pretty certain is that if the viscosity certification for Winter weighting is zero then the oil has to have at least a very large proportion of, if not entirely consisting of, Class IV or Class V base stock. For example, the oil National Tyre and Autocare is supplying for their £25* oil change is BP Visco 7000 0W-40. That they claim this is a full synthetic is believable.

For a comparison of the two most highly profiled 'full' synthetics, Amsoil and Mobil-1**, you may like to mill over their UOA (used oil analysis) data in one independent (supposedly) study here:

• Yes, it has just gone up, from £20. *&?@#!

I really think Castrol are evil, after what I've read of their case!! I'll never touch their oils again as long as I live.

R.

After using Mobil 1 for about 15 years, I've recently switched over to Motul E-tech 8100 ester-based full synthetic. Mobil is said to have dropped the ester base stock from their formulations.

John

I did a lot of reading into the different types of oils and settled on Silkolene Pro S 5W-40, which is also an ester-based synthetic.

I got it online for £33 (per 4 litres), Mobil 1 is £39 in Halfords, so I've got argueably a better oil for less :)

(Not that I have anything against Mobil 1, by all accounts it's excellent... but I think Silkolene is supposed to be even better due to the ester)

R.