What engine oil should be used

<table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr valign="top"><td>What engine oil should be used

contributed by Ian Simpson

Peoples opinion varies, so here's mine:

Qusetion: "What oil is best for a modded 5gtturbo?"

Possibly Mobil 1 fully synthetic 0W40.

It's good in my newly assembled 5GTT C1J engine. 5.2 bar oil pressure when cold, dropping to about 4 bar at idle, read from the original 5GTT oil pressure gauge.

Now the engine turns faster when starting, is better that it was when cold, the turbo spins better than it did when cold (almost like it's warm!), and it feels 'easier' when running, so I guess this oil is lubricating better.

I like it.

At the moment I feel it's better than the Castrol 10W60 fully synthetic. The turbo seemed to hold back with that in, especially when cold.

If you're worried about a 0W oil being too thin when cold, it's not too thin, as far as I can ascertain, the 0W rating is thicker than it's 40 rating. The oil gets thinner as it heats and is the same thickness at the 40 rating as any other 40 rated oil. These 0 oils don't contain much, if any, viscosity enhancer as they maintain their viscosity very well from 0 to 40 compared to cheap oils that do get too thin without the enhancers.

I did 1000 miles with Castrol GTX 10W40 for running in, up til about December '03. Then fitted the Mobil1 0W40 and the engine was smoother everywhere, better starting, and faster when cold. And smoother up at 5000rpm. It's seemed a bit faster at full power, or maybe that an effect of the weather at that time.

For a couple of years I used Valvoline 5W50 fully synthetic without smoke, oil consumption or loss of oil pressure according to the dash board gauge.

Per a conversation I had with Exxon Mobil: "Mobil1 is unique as it's a Tri synthetic. 0W40 is best for economy and engine / turbo protection but can get past seals as can other 40 grade oils so 15W50 might be best for motorsport but not so good for economy. Porsche recommend 15W50 for their cars older then 5 years."

A Sierra Cossie owning friend recently said to me that he ran his 120K mile engine on Mobil1 0W40 and it was fine except after a long run where, after backing off then powering on again he'd get a puff of smoke. This puff stopped when he changed to Mobil1 15W50.

A few people say Mutol Oil is better than Mobil1. See this thread.

The Price

(Probably obsolete now in Feb 2017, but in Feb 2004 I'd arranged with Mobil a discount for the RTOC to buy at trade price a quantity of Mobil 1 (either 0W40 or 15W50) so we can sell it to members for perhaps £27 for 4 litres.)

(In Feb 2004!) Costco sell Mobil1 for about £26 for a four litre bottle.

Parts if you're changing your oil

GSF for your oil fillter and sump washer.
And if you use your GSF privilege card you'll get it a bit cheaper.
GSF Part no: R12006 for the filter, about £6. They normaly supply you with the Purflux one same as Renault supply. Renault part no: 7700727482.
Sump plug washer (Renault part no: 7703062062). About 12p from Renault.

Changing the engine oil

bobistheoilguy.com

http://wiki.seloc.org/a/Oil_Labelling_Explained

18Feb2004

http://www.calsci.com/motorcycleinfo/Oils1.html
Added: 28Jul2011

If you think this article can be improved then don't hesitate to let me know in what way, if you have some suitable hard factual data on oils please send it to me so I can include it in this article.

Ian S RTOC Profile https://www.rtoc.org/boards/images/bu...iend-small.gif
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