Oil Specifications - Help

Submitted: Thursday, Jan 12, 2006 at 20:03
ThreadID: 29627 Views:24301 Replies:8 FollowUps:2
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Hi all,

I must start this threat by admitting I have very little knowledge on oil.
No doubt with all the knowledge members have on this forum, someone can set my straight.

I am a little confused about oil grades, i.e 15W/40, 5W/50 etc etc etc.
I went to get some oil for the Barina today and asked for MOBIL SUPER XHP 15W/40 as this was the oil recommended to use when I rang the mobil lube line.

The guy at REPCO didnt have that oil in stock and told me to run it on 20W/40as this is what the manufacturer recommends. He was going off a database in his computer. Thinking he just wanted a sale, I decided to go elsewhere to find the oil.

So I went up to SUPERCHEAP auto's to see if they had the SUPER XHP 15W/40. The guy at SUPERCHEAP told me to use MOBIL 1 5W/50. He said it would be better for the engine when I initially start it and that it will give greater protection (being a 50 grade oil) when the car is under load or running in hotter conditions.

I was now totally confused and decided to head home and post this thread on the forum.

Can someone explain to me the oil specifications. What is the difference between all the oils above and most importantly, what should I put in the

92 1.3lt Barina????? and what should I be putting in the 2000 3.4lt Manual Prado

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Reply By: 120scruiser - Thursday, Jan 12, 2006 at 20:46

Thursday, Jan 12, 2006 at 20:46
The thinner the oil the quicker the initial lubrication will be.
The colder the climate you live in the thinner the oil you need.
The thinner the oil, the less friction and resistance so the better the fuel economy.

Just to throw a spanner in the works, somebody who has the same vehicle in Sydney and Alice springs would run different oil. Because Alice is hotter you run a thicker oil.

For your 92 Barina I would run a 15w40 SL grade.
For you Prado I would run a 15w/40 or even a 10w/30 SL grade oil.
The SL is the important part.
The later in the alphabet the rating is the later model oil. For instance an SF grade oil would only be used in vehicles prior to 1985 where SL is the latest generation. It doesn't matter if you use Shell, Mobil, Caltex etc. Oil is like a cake. It is made to a recipe. All SL oils in 15w/40 grade are made to the same specifications.

An example - We changed to 10w/30 oil in some cars, as per recommendations, and a few customers came back and said "what did you do to my car last service?" I said why and they said it is getting an extra 100 km per tank. This was because we changed to the thinner oil.

The Mobil 1 is a fully synthetic oil and will cost you a fortune. It is good stuff but an over kill in my opinion.
You are recommende Mobil XHP because Holden uses Mobil just like Nissan uses Castrol. Thats the only reason. If you get 15W/40 for both you can't go wrong.
The 10w/40 semi synthetic is of similar viscosity and a beautiful oil if you want better. This is what I use.

Hope this sheds some light
AnswerID: 148148

Reply By: Exploder - Thursday, Jan 12, 2006 at 21:06

Thursday, Jan 12, 2006 at 21:06
I wouldn’t put in Mobil 1 5W50 as that is pretty thin and you will probably burn oil using it.

I am a little rusty on this topic OK, but this is the general gist of it

He is correct in saying it will offer protection in Hot temperatures as with a 50 Rating it will not thin out as much as say a 5W30 oil would so it will keep better oil pressure.
But a 15W40 would be better

15W40 would be fine as well as 20W40 you would get beater fuel consumption and engine response out of a.10W30 or 15W40 than a 20W40 or 50 but with a high K’s engine the 20W40 would give better protection.

5W is its cold Viscosity rating (resistance to flow) 5 is Low 20 is high
50 is The Hot Operation Rating a 50 will not thin out as much as a say a 30 will under trying conditions so it will hold better oil pressure.

Saying that if you use a oil that is too thin then you can overheat bearings and have dangerously low oil pressure.
Same as if you use a Oil that is too thick 25W60 or something you can starve bearings of oil and have to high Oil pressure

What oil to use depends on how the engine is built (Tolerances) this is way you should stick close to the manufactures recommendations, But as a engine gets older and part’s start to wear it may be necessary to move to a higher Viscosity oil to keep good oil pressure and lubrication.

Also wide viscosity oil (I.E 5W50) will tend to break down faster than a low viscosity oil (I.E 5W30) as it needs more additives in it.

Manufactures recommend oil to give good Pressure, Lubrication, protection and Fuel efficiency so a manufacture recommended oil will sometimes be over on the thin side rather than thick I.E a 5W30 rather than a 10W30 or 40.
To get right into it you can even look at NOACK Volatility, flash point and base number ratings but that’s going a bit far for a 1.3 barina

AnswerID: 148159

Reply By: Member - Royce- Thursday, Jan 12, 2006 at 23:23

Thursday, Jan 12, 2006 at 23:23
Oils is oils
AnswerID: 148209

Reply By: Member - Stephen M (NSW) - Thursday, Jan 12, 2006 at 23:29

Thursday, Jan 12, 2006 at 23:29
Hi there Jason, mate I had 2 barinas one a 90 moodel which I bought brand new then sold it 4 years later with 200 thou k on it. I then bought another one off my cousin a 1992 model in 98 after I bought my house, sold boat, bike,both my cars and used all the money for a deposit for the house so was left with nothing then when got back on feet again is when I bought the 92 model off cousin, 5 speed with air 2 door 1.3 as they all are that engine size. Mate I used whatever was on special, valvoline,shell,mobil,castrol,etc, all rated at 20w 50, I think for memory the shell was 15w 40 changed every 10k plus filter did nothing else unless it started to play up eg start missing oops needs new plugs, put the foot down not much power,oh must need a new fuel filter, thats how i treated it and i flogged the arse out of it,all day every day, even put a tow bar on it and had myself 110kg brother in law 120kg and my wife better not say but you get the picture, a fishing boat hanging off the back 15 foot aluminium plus a 30 hp out board from 7 hills to central coast and back with the air on as well, (had to turn off to get up mooney) didnt faulter even got some fish, moral to the story, dont be too fussy these things run forever loved being revved remember the gti's, I could not kill it even had near a ton in the box trailer when I was getting things for my house eg garden soil rocks etc. They are a very rattly motor from new not quit by any means but I think they are fantastic oh yeah and will use about 6/7 L per 100 klms. We even took ours to noosa on our honey moon from penrith and I sold that one with nearly 300 k on it, bloody brillant, will last you for yonks just do regular oil changes and youl be right. Regards Steve M Ps wouldnt waste your money on synthetic oils for the barina anyway
AnswerID: 148211

Reply By: Ron173 - Friday, Jan 13, 2006 at 09:19

Friday, Jan 13, 2006 at 09:19

go to any of the big oil company sites, shell, castrol, mobil etc, they all have a vehicle product identifier, where you will get the correct oil from that particular manufacturer for your vehicle.

AnswerID: 148244

Reply By: Member - Oldplodder (QLD) - Friday, Jan 13, 2006 at 09:29

Friday, Jan 13, 2006 at 09:29
Good points in previous posts.
Just to help with the numbers, which are viscosity ratings.

From memory (could be wrong in the detail, but you will get the idea) the old way of measuring viscosity was to have a tray sloping at 20 degrees, and measure in seconds the time it takes the oil to run the length of the tray. I think it used to be 24" long ?? 15 was 15 seconds, 50 was 50 seconds.
So more viscous the oil, the more it sticks to the side of the bore. More iit sticks to the side of the bore, the better protection, but also the thicker the oil, the more power it takes from the engine to pump around and for the rings to side up and down. Friend found that the oil pump can use 3 to 5 hp to turn over, plus the friction. In his racing engine, got an extra 8km/hr on the end of the straight by going down to a lighter oil. He changed it after every race anyway.

Of course, oils these days arn't straight mineral oil any more, but have all sorts of friction modifiers etc, so viscosity is not the only guide to protection. Then there are synthetic oils.

the 15w/50w means 15w viscosity at room temperature, and 50w viscosity at 70 deg C when the oil has warmed up. They do this with polymers that change with temperature.

My old beetle used to use a single viscosity oil. All that they made up to the 60s.
Under 0 deg C - 10w, under -15 deg c, auto transmission fluid (5w), 0 to 20 deg C, 15w, and over 30deg c, 30w. Some people used to run a different weight oil in winter and summer.

So what both blokes at SC and repco told is most of the truth.

What does it say in your manual?

AnswerID: 148248

Follow Up By: Ron173 - Friday, Jan 13, 2006 at 09:47

Friday, Jan 13, 2006 at 09:47
Well said.

Viscosity.... 'is the ability of an oil to resist shearing forces'..... thats the text book answer.

FollowupID: 401491

Follow Up By: Member - Oldplodder (QLD) - Friday, Jan 13, 2006 at 17:16

Friday, Jan 13, 2006 at 17:16
From memory, one of my old reference books on oil and greases refers to this method of test as the SAE (Society of Automotive Engineers) tests used in the 1920s or 1930s. Gives the idea anyway.
FollowupID: 401613

Reply By: charlie horse - Friday, Jan 13, 2006 at 12:17

Friday, Jan 13, 2006 at 12:17
Go with the Oil Manufacturer they make the Oil

Try this web Site http://www.datateck.com.au/lube/mobil_au/ for Mobil
AnswerID: 148272

Reply By: Jason (macca) - Friday, Jan 13, 2006 at 19:34

Friday, Jan 13, 2006 at 19:34
Thankyou very much to all those who replied. I appreciate your time and thank you for going to the trouble

AnswerID: 148388

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