I recently did a oil change and put mobil1 in which seems to have caused a leak from the rear crank seal due to it being "thinner" , I removed a bit of oil and placed some wynns super charge for oil in to thicken it up slightly which seems to have alleviated the rear crank seal leak.

Am I right in thinking that I still get the enhanced benefits of synthetic oil but with it being slightly thicker? ( i just spend a short while longer in the morning before i boot it )

Hi mate,

 

Mobil-1 oil is for some reason very thin despite its viscosity rating of 0w40 (the "40" bit being the thickness and ability to flow when hot).

 

Oil additives are generally bad news in any high performance engine and you are best off chosing a decent oil in the first place - they normally contain the same ingredients as oil additives anyway.

 

If your engine is stock (or very lightly modded) then a "40" graded oil is more than sufficient. After all, Nissan specify a 10w40 for most needs.

 

I would drain out the Mobil-1 and refill with another decent fully synthetic of either 5w40 or 10w40 (or a "50" rated oil if heavily modded). I use Shell Helix Ultra 5w40 and have no probs or leakage and textbook oil pressure (UK spec car, 84k miles).

 

I used Mobil-1 0w40 in my old Supra and for some reason the oil pressure dropped significantly when hot. After reverting to CAstrol RS 0w40 or Shell 5w40 the pressure returned to normal and oil consumption decreased dramatically. For that reason I have NEVER used Mobil-1 0w40 in my ZX.

 

Richard :)

Thanks mate

Am looking at a 10w-40 at this very moment from amsoil

anyone heard of what their oils are like?

Semi Synth is more than adequate bud!-Magnatec 10w40 for instance.

how far do we push the tuning on these cars before we go fully synth?

To about Macca's stage! LOL!

ohhhhhh..thats never for me then

Semi Synth is more than adequate bud!-Magnatec 10w40 for instance.

 

True - especially as most of us have it changed every 3000 miles anyway.

 

However fully synthetic will always be better - especially for the turbos - and the prices are not too different to prohibit buying fully synth either.

 

Richard :)

I was told 10-50 so thats what I put in.

i use Mobil Synt S 5W40 (fully synth) with no probs

how far do we push the tuning on these cars before we go fully synth?

 

Depends on your mileage. (This is not a plug, and I'm not affiliated with Opie in any way.) Simon at Opie (Oilman) recommends Silkolene Pro S 10w50 which is what I use. Think that's his recommendation if your car has less than 100k miles on it, not sure if it changes above that. All I can say is that my car runs great on it.

Oh yeah, don't use additives. Everything I've ever read about oil by anybody who really knows about it says don't bother. For example, try this:

 

http://www.carbibles.com/engineoil_bible.html

Been using Castrol RS0-40 for over 5 years and now its way past 140kmiles UK spec original turbos no oil leaks. So far so good:)

I used fully synthetic in my UK TT @ 120K Miles.

New shortie TT is at 70K @ Im about to stick semi-syn magnatec 10/40 in it.

Never had a problem with using that in my old zed and its what nissan recommend.

True - especially as most of us have it changed every 3000 miles anyway.

 

However fully synthetic will always be better - especially for the turbos - and the prices are not too different to prohibit buying fully synth either.

 

Richard :)

How is fully synth better for turbos matey?

How is fully synth better for turbos matey?

 

Semi synthetic doesn't hold the same heat properties as fully synthetic. Turbos get that much hotter than anything else, fully-synth will retain its properties for a longer period of time, ie, it won't get too thin and become useless, that's in extreme cases though.

ok Si, nice one

so for TT's its best to go for fully synthetic then.

 

What are we recommending then - 10/40 Fully Synthetic.

Depends, if the engine is stock, semi should be ok but fully is best.

a decent semi synthetic more than meets the spec of turbo engines.

 

TBH, fully synth is a complete waste of money if like most people on here you change your oil every 3000 miles or so!

 

I only use fully synth cos its free!! :D

so are we agreed again on Magnatec 10/40 and oil & filter changes every 3K Miles

I use Vauxhall 10W40 semi synthetic. It's an oil developed by Texaco. I get it Trade for about £6 for 5 litres...rrp is nearly £20 for that. It's very good quality oil.

sound. I think one of the ex-traders used that too.

...oil leaks from the main seal can be a sign of blocked or poor standard PCV valves - might not be an oil problem.

 

Good luck

 

Jack

Fully synthetic is better for turbo because it is more thermally stable at high temps meaning that it stays in grade for longer.

 

We recommend 5w-40 for stock road cars and 10w-50 for modded/track cars.

 

Cheers

Simon

http://www.opieoils.co.uk