Thread: Using synthetic oil 2.5 Petrol?

some of the runnyer ( tech term ) oils may not be so good when the temps go up. I am considering using a thicker oil in the summer and reverting to 40 weight in the winter just in my 110 to ensure the oil pressure stays up when it is hot. the gauge shows when the oil cooler kicks in with a noticeable drop.

If experimenting watch the gauge and ensure it is a recently calibrated one. Ensure you are using a high detergent oil

Originally Posted by LandRover110

I have a 2.5 petrol in my 110 (1986), and using 15w40 oil, wondering if I can use fully synthetic (10w40 or even 5w30) does anyone has tried this? or is it just too thin and will it leak out.....

Have a read at bobtheoilguy about oil viscosity and synthetics. I read that mineral oils have additives to make them thicker (second number eg -30, -40) , so when additives wear out, oil thins. Synthetic oils start at the higher number and have additives to reduce viscosity (lower number 5W, 10W) so are better as oil ages as viscosity doesn't drop. I use synthetic where possible in all the cars I care about. Been doing this since 1985. Mineral oils degrade and sludge more.

Just something to note..

keeping it very basic;
*Oils that are labelled "PAO and/or ESTER" (polymer) base are full synthetic engine oils.
*oils labeled "full synthetic" but make NO mention of "PAO and/or ESTER" are not "full synthetic", its a legal loophole used by oil companies, due to the way they crack the crude oil molecule.
*You are better looking for oils with higher resistance to mechanical shear, this is listed in product data as VI (Viscosity Index).
*The more viscosity extenders/stabilisers (additives etc) an oil has, the less resistance it has to mechanical shears.
*Sludge in an engine is caused when an oil (or rather the additives) break down due to mechanical shear, once an oil has separated due to mechanical shear, its resistance to mechanical shear is greatly reduced.
*Modern engine oils (labeled full synthetic or not) are so much more advanced than oils of old they are anything but plain old mineral oil.

*A modern multi grade engine oil such as a semi-synthetic 5W40 will have the protection and the VI rating of a SAE 40 (a single grade engine oil) at that testing standard of 100 deg C, but will have that ever so important cold VI engine starting of a SAE 5 oil.

This is all greatly simplified, but the basics are there. The best thing you can do with your 2.5lt Petrol is change the oil on a regular basis (as with any engine) being a naturally aspirated petrol engine its not under any great stress.

Regards
Daz

i know it's hard to believe with a land rover engine, but synthetic oils seem to escape much faster than mineral oils!

I like this explanation to keep it simple

http://www.mobil1.com.au/academy/what.aspx

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