Oil

In Golf+ this month there's a question from a reader as to whish viscosity oil is best for the mark1. Steve "the brain" Cresswell from C&R Enterprises answers by saying that higher viscosity oils are better ie 15w/40 etc as with lower viscosity oils the pressure can fall too low once the oil heats up and thins. I've always used Quantum Synta or magnatec in mine thinking the most up to date synthetic or semi-synthetic is the best, but now I wonder. Any thoughts anyone? :dontknow:

hi,
 dont quote me on this, but i would tend to go for a "thicker" oil, and not to go for fully synthetics.
 i would use the thicker oil mainly due to engine age and wear. unless youve got a baffled sump then i would think that the thinner oils would be poorly distributed under hard use and cornering?!?!?!

 but as i say, dont quote me on this!!!
 
 Jon

Try here

http://www.vwgolfmk1.org.uk/modules.php?name=Forums&file=viewtopic&t=4491&highlight=oil+change

I use 10w40 semi synthetic in my mk1 diesel and my citigolf and my GX,great in the summer and not thick for the winter,my citigolf and my diesel have oil pressure guages,when the engine in the diesel is HOT after a run from brighton at idle the oil pump pressure on the guage shows 2.5 bar,when revved to 1500 rpm it shows 8 bar on the guage,when first started it stays on 10 for ages.The citigolf has a guage that goes to 5 bar,when cold it stays on 5 bar until hot,(cooling fan in) and when i drove it to bristol for a photoshoot the pressure dropped to 3 bar at idle,so 10w40 is fine,90% of the cars i service every day use 10w40 apart from new vw pd tdi engines and the ford zetecs.
I buy vauxhall semi synthetic very cheap,vauxhall trust it in there 16v and turbo diesels so must be ok :wink:
Tommo320 has it too  8O
Bert

10W/40 is thicker than 15/W40 - if you compare the cold viscosity of the 10W with the warm viscosity of the /40 part. the "W" part of the rating means that its a multigrade and the oil has viscosity modifiers which make it thinner in the cold, than a monograde in the cold. But, its still always thicker in the cold than the warm. So, you can safely switch from 15W/40 to 10W/40 or 5W/40, and gain the benefits of modern, or semi-synth, or fully-synth oils. Now, whether there is a long term benefit is another thing, since you'd be changing at the regular intervals anyway - or are you looking to extend the service interval?

Its true that a 10W/30 is thinner than a 10W/40 once warm. It sounds like the advice in Golf+ magazine is based on misinformation about oil viscosity!

This might be a stupid question but what unit do the numbers represent?inches, pounds, milliletres, fathoms?

I think its an arbitary unit. Here is a link to the original thread on the subject, which is really detailed:

http://forums.mercedes…php?t=11869&highlight=oil