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MG MGF Technical - What oil ?

Just been looking on the site and found myself with a dilemma, what oil should I use in my car ?

I was going to follow the handbook but numerous people have quoted different options ranging from 0/30 to 10/40 and makes from Castrol to Halfords.

I have a 2002 1.8 mgtf
P Saunders

Bought my F new back in 98 and have used nothing but Castrol GTX Magnatec 10W-40 - with no problems at all.
Steve P

A 0W30 will be thin at start up with good oil flow and increased mpg but will also be thin when hot. However base oils are not the same and some thin less when hot than others. It is therefore worth checking HTHS of oil which is measured at 150c rather than 100c. A number of years ago the SAE determined that a minimum HTHS of 3.5 was required for minimum wear (M10W40 is 3.6).

The base oil is also key as to the length of oil change intervals. In US Mobil have a range of oils based on this
Mineral 5k
Semi 7.5k
Synthetic 15k

Magnatec is basically mineral with its special additive for clinging to metal. This special additive is an ester oil found in virtually all synthetic oils in greater quantity, so do not be misled by adverising.

Mineral oils in order to thin less when hot use viscosity improvers, which easily breakdown in use, hence one reason for shorter oil change intervals.

The optimum oil for road use is one that thickens less when cold and thins less when hot with minimum viscosity improvers, which IMO is a 5W40 Synthetic.
Paul Wiley


I've got a 2003TF and since the closure of MGR (and the end of my warranty) switched back to Mobil one (0/40)which I used to use in my last car.

This is more a personal choice from my old car, when I tried the Magnetec 10/40, it used to be very loud when cold and quieter once warned up but found the opposite with Mobil which is what I think Paul is saying above. But I used to do shorter journeys in the old dear, three miles to work, three miles back so the Mobil was probably better as the engine had hardly warmed up before I was home again!

And now in the TF, I'm doing an average of 13 miles each way and the mobil runs cooler than the magnetec oil once the engine has warmed up (whatever I can do to keep the engine temp in check).

What sort of useage does your car get?


john ip

Thanks for all the help.

John, on weekdays I travel 20 miles to work in the morning and the same in the evening, weekends vary depending on what I am doing (refereeing during the football season and playing cricket during the summer). Do you recommend the 10/40 oil ?
P Saunders


I would go for the 0/40 mobil (there are various other choices, castrol have just introduced a new oil called edge).

Or Halfords do their own oil, fully syth in 5/40 I think. This fits into what Paul was saying and is about half the price of mobil.

Oh, and will give you slightly better mileage and runs the engine cooler which gives me peace of mind from the old HGF (I know there are other factors but at least I'm keeping the operating temps down which surely must help!).


john ip

This thread was discussed between 31/07/2006 and 02/08/2006

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