What oil is best?

Hi everyone, I was hoping to get a bit of clarity on what oil is best for my 1983 1.8 mo1 golf gti. The car has 200k on the clock. From what I have read opinions are divided between 10w40 and 15w40. I was hoping to get the best option for the car as the mileage is quite high. Thanks in advance 

VW's only stipulation was that oil conforming to either VW 500.00 (standard for "improved lubricity" oils, now superseded by 502.00) or 501.01 should be used. This applies to all engines on Golf Mk1 from 1974 to 1983, plus Golf Cabrios from 1979 to 1993.

For 502.00 spec oils, the exact viscosity range is pretty irrelevant. VW's maintenance manual for for 1986-on Golf Cabrios dated November 1994 lists a variety of possibilities for 500.00 oil - 5W-30, 5W-40, 10W-30 and 10W-40 - which I imagine would also be applicable to earlier cars. The ambient temperature range for all of these viscosities is -30 to +35 deg C.

For 501.01 oils, the ambient temperature ranges are much more restrictive. For ambient temperatures above 15 deg C, only 15W-40, 15W-50, 20W-40 and 20W-50 are suitable.

So my reading is, if you stick to oils conforming to VW 502, you should be fine with any viscosity between 5W-30 and 10W-40. However, if you use a cheaper VW 501.01 oil, don't use a viscosity less than 15W-40

What I have Fond from Driving these beasties since the late 80's is on thinner oils ie: 10w-30 you have to use a high quality filter, and not a FRAM, BOSCH, Generic, or store Branded.

They fail to have the drain back valve (Yes Bosch has Cost reduced theirs.) which helps to maintain idle oil pressures (flickering light from hades).

I have been driving 4 Cylinder cars since 1972, Austin Healy Sprites, MG Midgets, Rover 3500S (v8) and Toyota.  I always used 10W40 with no issues in -20F-100F conditions, and never had issues.

Later on with my re-introduction to Dubs, 1990-1993 Cabriolets in the Deep South where road temps could reach 130F temps I found that 20W-50 was preferable and again a good filter.

On my 80 Diesel Golf Rotella 10W40CC/CD or 10/30CC/CD

I only had my Diesel from 1980-2000, and Changed my filters often, my Fuel Filter every 4-6 months.  

Just my 2 Pence.

With the advent of Synthetic oils they can thin with the engine temps, and I have found that they work better with a Quality filter.

Filters that I have used for oils that never caused a flickering oil lamp are:

WIX,
NapaGold (WIX Store Brand)
Pureolator Gold (not the White one.)
STP
Mobil-1
Mann
Mahl
Genuine VW

Fram, Bosch, Pureolator White, Store Branded all caused me flickering oil light issues at idle while I was running 20w-50.

I use the genuine vw filter. I have looked at some oils and found 10w 40 liqumoly but it's fully synthetic. What would be best suited mineral, semi synthetic or fully synthetic?

Liqui Moly 10W-40 is described as "based on synthetic technology" so probably semi-synthetic. The spec says it only meets VW's lower 501.01 standard, so with that viscosity, only suitable for ambient temperatures up to 15 dec C according to VW. Your safest bet is to stick with VW 502.00 standard oils.

Whether an oil is mineral, semi-synthetic or fully synthetic isn't that relevant. The additives used are equally important. Most oils meeting VW's 502 standard seem to be semi-synthetic oils, but not all semi-synthetics meet the VW 502 standard. I wouldn't chose an oil that doesn't comply with VW's 502 standard. There are loads on the market that do - just check the spec sheet online or the back of the container

Perfect thank you. I've found shell helix hx7 10w40 vw 502. 

That one also seems to be a VW 501.01 rather than 502. A lot of VW 502 spec oils seem to be 5W rather than 10W. I use VW Special G 5W-40

On some websites it says 501 but on shells website it says it's 502

Scratch that shell helix h7 is 501 sorry Fuchs TITAN SYN MC 10w-40 High Performance Semi-Synthetic Engine Oil is vw 502 and a lot cheaper

Thanks everyone