which engine oils in your scooby?
 

Just about to do an oil change,ive used silkolene pro s 10w60 and mobil 1 15w50 before and cant really tell them apart, just curious to know what the majority of u use?

depends really on use (and to a large extent personal preference...)

we always use either Motul 300V 15w50 or Millers 10w60................on odd occassions pro-s 5-40 (dependant on age)

alyn - asperformance.com

The most popular choices seem to be :-
Mobil 1 15W50, Castrol RS 10W60 and Motul 300v ;)

Cheers

i put Shell Helix 5w 40 in mine as i do alot of short journeys.

Mobil 1 Super S 10-40 SemiSynth. @ 110.000 KM

cheers everyone ,i`ll probably go with the motul or mobil 1 again dont really like thought of thinner oil in scoobs too many of me mates have had crank trouble and they`ve been told the thin oil hasnt helped although faulty oil pumps have also been a factor in a couple of cases.

motul 300V,15-50 for me due to lots of dragstrip activity

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I do short journeys also what do you call short journeys? I go to work say 5 miles, finish work 5 miles and then at weekends maybe 30 miles max ? Is that what you class as short. I am due my 1000 muile service in 2 weeks and wonder what oil to put in??

I have just changed to motul 300v and i don;t think its the right choise, the tappets on my leg now sound really bad and they dont go away either. I too do alot of short journeys!

Comper100

I use Silkolene Pro S 10W50.

I USE MILLERS SEMI-SYNTH 10-40

Yeah sounds about what im doing. Ocasionally on a weekend i may go further.

I went for this oil as i believe this thickness is better for a car that isnt going on as long a journey as most cars. ie it will get upto temperature sooner.

Used to put Castrol RS10/60 in, but don't bother putting oil in at all now, as everyone tells you it's wrong, no matter what you choose! Probably gonna run it with no air filter as well......I mean, what harm can it do? Btw, also using circa '77 Allegro plugs as well, and I've thrown the intercooler in the skip, cooling the charge temps, load of bollox........

dlynch,

The choice of oil is often a dilemma. However, your choice is small as you shouldn't be choosing fully synthetic until about 10k miles.

Should i just let the dealer do his stuff then ?

That would probably be the best thing to do. Check out http://bbs.scoobynet.co.uk/showthread.php?t=346896 for much information about oils.

i go with castrol rs 10/60

Check the group buys.

Cheers
Simon

another for castrol rs 10/60 but i'm runnig a 300hp sti and was told to run fully syn

mike

Whilst RS10w-60 is labelled as fully syn, it isn't one in the true sense of the word, it's a hydrockacked mineral oil (petroleum based) and not made in a laboratory by chemists to be pricise.

Obviously there are advantages to using a proper synthetic oil which you will find in other posts I have made, here's some information:

SAE has a test called HT/HS (High Temperature/High Shear) current tests are done at 150 degC.

The higher the HT/HS number the better because this indicates less shearing. Petroleum oils tend to have low HT/HS numbers which barely meet the standards set by SAE. Because petroleum oils are made with light weight basestocks to begin with, they tend to burn off easily in high temperature conditions which causes deposit formation and oil consumption.
As a result of excessive oil burning and susceptibility to shearing (as well as other factors) petroleum oils must be changed more frequently than synthetics.

Not all multi-viscosity oils shear back so easily. True synthetic oils (PAO’s and Esters) contain basically no waxy contamination to cause crystallization and oil thickening at cold temperatures. In addition, synthetic basestocks do not thin out very much as temperatures increase. So, pour point depressants are unnecessary and higher viscosity basestock fluids can be used which will still meet the "W" requirements for pumpability.

Hence, little or no VI improver additive would need to be used to meet the sae 30, 40 or 50 classification while still meeting 0W or 5W requirements.

The end result is that very little shearing occurs within true synthetic oils because they are not "propped up" with viscosity index improvers. There simply is no place to shear back to. In fact, this is easy to prove by just comparing synthetic and petroleum oils of the same grade.

Synthetics will generally have significantly higher HT/HS numbers. Of course, the obvious result is that your oil remains "in grade" for a much longer period of time for better engine protection and longer oil life.

What is a VI Improver?

As a lubricant basestock is subjected to increasing temperatures it tends to lose its viscosity. In other words, it thins out. This leads to decreased engine protection and a higher likelihood of metal to metal contact. Therefore, if this viscosity loss can be minimized, the probability of unnecessary engine wear will be reduced.

This is where viscosity index (VI) improvers come in.

VI improvers are polymers that expand and contract with changes in temperature. At low temperatures they are very compact and affect the viscosity of a lubricant very little. But, at high temperatures these polymers "expand" into much larger long-chain polymers which significantly increase the viscosity of their host lubricant.

So, as the basestock loses viscosity with increases in temperature, VI improvers “fight back”
against the viscosity drop by increasing their size. The higher the molecular weight of the polymers used, the better the power of "thickening" within the lubricant. Unfortunately, an increase in molecular weight also leads to an inherent instability of the polymers themselves. They become much more prone to shearing within an engine.

As these polymers are sheared back to lower molecular weight molecules, their effectiveness as a VI improver decreases. Unfortunately, because petroleum basestocks are so prone to viscosity loss at high temperatures, high molecular weight polymers must be used. Since these polymers are more prone to shearing than lower molecular weight polymers, petroleum oils tend to shear back very quickly. In other words, they lose
their ability to maintain their viscosity at high temperatures.

Synthetic basestocks, on the other hand, are much less prone to viscosity loss at high temperatures. Therefore, lower molecular weight polymers may be used as VI improvers.

These polymers are less prone to shearing, so they are effective for a much longer period of time than the VI improvers used in petroleum oils. In other words, synthetic oils do not quickly lose their ability to maintain viscosity at high temperatures as petroleum oils do.

In fact, some synthetic basestocks are so stable at high temperatures they need NO VI improvers at all. Obviously, these basestocks will maintain their high temperature viscosities for a very long time since there are no VI improvers to break down.

You will find an excellent article on this forum entitled "lubricating a Subaru"

Cheers
Simon

I use Motul 300V in my MY00 any of the named brands above will be good though :)

i take it you know a little about oils then oilman:D:D:D:D

Oilman,

You quoted
HT/HS
Silkolene PRO S 5w-40 = 4.07cp

Silkolene PRO S 10w-50 = 5.11cp

Silkolene PRO R 15w-50 = 5.23cp

Comparison to RL and M1

5W-30 3.8 (M1 3.08)
10W-30 3.8 (M1 3.17
5w-40 4.6
10W-40 4.7
15W-50 5.8 (5.11)
20W-50 6.1

Motul Data Sheets here http://turbofrogperformance.com/Tech.htm

REDLINE 10W40

The Silkolene figures are from the API test no ASTM D4683 which is conducted at 150 degC.

The only way to compare these HT/HS numbers is by putting oils of the same viscosity side by side i.e. 5w-40 vs 5w-40.

The Silkolene numbers are good as the higer the number the better.

We tested Redline 15w-50 this week and the chemical trace was very similar to PRO R 15w-50 as they are both ester based oils.

Cheers
Simon

Simon,
"the lower the number the better"? Are you sure about that?

Second graph on this page http://www.synthetic-oil-tech.com/d....il_testing.htm

Apologies, typo, the higher the better.

Cheers
Simon

Interesting that the Motul datasheets show that SWRT use 5W-40 rather than 15W-50. Also has STI using 10W-40 and Prodrive 15W-50 so even the top dogs differ.

Get your crosses and garlic out, I currently use Mobil 1 0W-40 in my STi8 PPP, 18000 miles with no prob, it goes better on "thin" oil (and I do rag it). Might try Motul 5W-40 at my next change, it's cheaper in the Hull Larkspeed shop than Mobil is in H/fords. I'm inclined to think cold circulation and low drag is very important hence my favour of 0W or 5W oils despite some strong opposing opinions on here. Maybe time will tell, as I'll continue with thin.

Maclaren F1 team use Mobil 1 0W-30 (admittedly with an altered additive package) so the stuff can't be that bad. I don't imagine they find much wear after 200 miles they just have to rebuild because major components have reached the end of their fatigue life.

Cheers, Diccy.