Originally Posted by tommo76
I drive a 3.0 GTV and i use the same, semi-synth 10/40W, and from what i've read this appears to be correct. I don't think there is a problem mixing makes, don't know about semi/full though.
Impressed at only one litre of oil in 7000 miles, mine seems to do a litre in 1000 miles! However no telltale pool on the garage floor or blue clouds out the back so i try not to let it worry me too much!
There are a lot of oils out there, some good some bad, Its nod a good idea to mix oils as it can affect the fine balance of the additive packs in them.
This might be of interest,
Oil is very much a personal choice and people tend to stay loyal to a brand or a product if it works for them.
There are many debates on car forums about the right oil but its not always easy to assess the quality of an oil without the technical data which is not always available to the public.
One thing is for sure, you always get what you pay for. Good quality oils with high grade additives and more importantly good VI Improvers (to prevent "shearing down") are expensive to make and therefore it will be of no surprise that cutting corners is an often used commercial method of bringing "cheap" oil to the market.
There are many types of oils labelled synthetic on the market today which range from HC (Hydrocracked) / MC (Molecularly Converted) Mineral oils through to PAO's (Poly ***** Olefins) and of course "Esters" which have been used in the aviation sector for years because of their durability and superior levels of protection.
It's a minefield and the choices are infinate but don't be fooled by some of the pretty cans on the shelves which say "synthetic" but in reality contain a very small percentage of the good stuff.
If you'd like to look at some good technical data on oils then you'll find loads of good information here.
I have been watching the oil threads on this forum for a while now, it's interesting reading.
You have very performance cars, many of which are modded or re-mapped, you should consider the best oil you can buy for "shear stability" and protection when the engine is being used hard.
The last thing you want to do is put an oil in that's an sae 40 but shears down to sae 20 within 2000 miles!
You don't have to take my word for it but the oil is the lifeblood of the engine, your cars require good ones.