Subject sez it all really...

I'd do a search, but it's down at the moment.

I've got a UK MY95 5dr. It's just had a service (69K), of which I think they've put in semi-synthetic...

If I top it up with full synthetic, will this harm the engine? Or should I drain the old stuff out first?

Thanks in advance,

Dan

It doesn't matter what you top up with, all oils are intended to mix with each other. There's been lots of posts recently about this, some favour semi-synths like Castrol Magnatec 10-40 and others say full synths like Esso Ultron 10-40, Mobil 1 Motorsport etc.

Who did the service, and can you find out what they used? Generally, for normal road use (not track days etc) a well-known brand semi-synth or full synth of 10-40 or 15-50 viscosity should be fine if you stick to the normal change intervals, don't cane it from cold and let it cool down after a blast.

Hope this helps

thanks

Dan