Oil advice and recommendations here!

[opieoilman]

Firstly the HT/HS number is a good way of identifying a decent oil as the higher the number the higher the resistance to shear which indicates the quality of the basestock used.

Hope this answers the viscosity questions, if not feel free to ask away.

Oil viscosities are accurately measured in units called “Centistokes” at exactly 100 degC. These fall into five high temperature SAE catagories:-

SAE No. 20 30 40 50 60
Viscosity Range 5.6 - <9.3 9.3 - <12.5 12.5 - <16.3 16.3 - <21.9 21.9 - <26

A decent quality oil usually has a viscosity that falls in the middle of the spec, so a SAE 40 will be about 14 Centistoke units, but SAE ratings are quite wide, so it’s possible for one 40 oil to be noticeably thicker or thinner than another.

When the polymer modified multigrades appeared, a low temperature range of tests were brought in, called “W” for winter (it doesn’t mean weight).

These simulate cold start at different non-ferrous monkey endangering temperatures from –15 degC for the 20w test to a desperate –35 degC for 0w.

So, for example, an SAE 5w-40 oil is one that has a viscosity of less than 6600 units at –30 degC, and a viscosity of about 14 units at 100 degC.

Now, those of you who have been paying attention will say “Just a minute! I thought you said these multigrade polymers stopped the oil thinning down, but 6600 to 14 looks like a lot of thinning to me!”. Good point, but the oil does flow enough to allow a marginal start at –30 degC, and 14 is plenty of viscosity when the engine is running normally. (A lot more could damage the engine. Nobody uses the 24 viscosity SAE 60 oils any more.)

The vital point is, a monograde 40 would be just like candle wax at –30 degC, and not much better at –10 degC. It would even give the starter motor a fairly difficult time at 0 degC. (At 0 degC, a 5w-40 has a viscosity of 800 but the monograde 40 is up at 3200!)

Cheers
Guy

[opieoilman]

Incorrigible said:

Guy you are a foutain of knowledge And to hijack the thread slightly Will a GL5 grade gearbox oil be OK in my Caterham diff and gearbox (build manual only says "EP90" but the handbook (which isn't for my car specifically) sayf use a GL4) Cheers Ben

Ben,

Yes what you are looking for is a GL4/GL5, there is a difference with this. A straight GL4 has been designed to help syncromesh gearboxes work smoother, the GL5 is more known as a diff oil because of its load bearing qualities but can affect the syncromesh componants, a GL4/GL5 is happy in a gearbox and happy to take the kind of loads generated by a diff.

Hope this makes sense.

Cheers

Guy.

[opieoilman]

Yep,

I thought it might say do not use GL5, this is where the GL4/GL5 comes into play. GL4 syncromesh properties and GL5 load bearing properties. It is confusing I know but a GL4/GL5 will be happy in both.

Cheers

Guy.

[opieoilman]

Incorrigible said:

OK, sorry when you said GL4/GL5, I though you meant either I went to the motor factor to change the wrong oil and they said that all the oils bar one was a GL5 and that GL5 was the "new standard" I assume that was bollocks Anyway managed to get a 80/90 GL4, and it was a quid cheaper, and it's in the car now so I'm not fg changing it

Yep,

It took me a while to understand this one fully.

Just to really confuse things there is now a GL6. The GL5 is a new standard as most modern (2000 onwards) cars call for GL5, but to combat the syncromesh problems of the other cars out there they made the GL4/GL5 to do both.

Cheers

Guy.

[opieoilman]

Wayne,

In my opinion the 0w-40 is too thin for the V8 hence the noise.

Mobil 1 is a top quality PAO synthetic, just the wrong grade the Mobil 1 15w-50 would be better, or a 10w-50 to be ideal.

I would look at Motul, Silkolene or Mobil.

Cheers

Guy.

[opieoilman]

jeremyc said:

My owner's guide just gives a list of acronyms and a complicated chart of oil grades for average ambient temperatures. So, what do I need that conforms to: API SJ/CF, ACEA A3/B3 and ILSAC GF2? It'll be road use, mostly in the average ambient temperature of Great Britain.

For which one of your cars?

[opieoilman]

jeremyc said:

opieoilman said: jeremyc said: My owner's guide just gives a list of acronyms and a complicated chart of oil grades for average ambient temperatures. So, what do I need that conforms to: API SJ/CF, ACEA A3/B3 and ILSAC GF2? It'll be road use, mostly in the average ambient temperature of Great Britain. For which one of your cars? The DB7 Vantage. Does it make a difference which one it's for providing the oil conforms to the specs?

It does make a difference because you need to get the viscosity right. Not only that just because the oil conforms to the specs does not mean its any good, like cheap home brand coke cola from a supermarket, conforms to the specs for human consumption but it is not good by anymeans.

The RS2 for egsample, all VW engines do things by codes, your oil for the RS2 will need to meet a VW spec regardless of normall specs.

The Caterham for egsample, it depends on what you would use oit for, different grade for different uses and dry sump or not etc.

The Vantage for the UK climate I would go for a 5w-40, which is suitable from -30 to +40 deg and is the most common range for our cars to be in with our wonderfull climate.

Yes any oil that conforms to the specs you mention would do, but I would look for a "true" synthetic that does not use petroleum base stocks, but is made up of PAO or Ester base stock.

It would be shame not to do the best for a Vantage.

Cheers

Guy.

[opieoilman]

jeremyc said:

opieoilman said: The Vantage for the UK climate I would go for a 5w-40, which is suitable from -30 to +40 deg and is the most common range for our cars to be in with our wonderfull climate. Yes any oil that conforms to the specs you mention would do, but I would look for a "true" synthetic that does not use petroleum base stocks, but is made up of PAO or Ester base stock. Thanks for your help. Which brands of oil are a true PAO or ester base stock synthetic that comply with these specifications then? >> Edited by jeremyc on Friday 29th October 17:39

Look at something like Motul, Silkolene, Mobil, Redline. they all do great true synthetics.

We are in the process of becoming a sort of trader on here, but in the mean time e-mail me through my profile and I will forward on what I have to offer.

Cheers

Guy.



>> Edited by opieoilman on Friday 29th October 17:47

[opieoilman]

Way off grade mate.

You need a good synthetic 10w-40 or 5w-40 for better cold start.

You can always email me.

Cheers
Guy

[opieoilman]

pwig said:

Is there any particular oil you would reccomend?

Yep, I would use a synthetic 5w-40 or 10w-40.

Plenty to choose from here:

www.opieoils.co.uk/lubricants.htm

Cheers
Guy

[opieoilman]

GregE240 said:

Hello Guy, Only just stumbled across this thread! Thank you for the assistance and wise words thus far. Its been a great read. I have been a convert of synthetic oil since the early Nineties. I ran an XR2 from 28K - 146K using only Mobil 1 every 6,000 miles. When I sold the car, it still did not use any oil at all between services, the oil always a nice golden colour when it was drained. After that, my wifes 2 MX-5s were run on fully synth, as is my Mercedes and her Porsche. My own bugbear for your perousal is the Merc. I've a 1998 E240 with the 2397cc "112.911" engine. It has 121K on the clock. It has a full dealer service history. For its entire life the car has had a diet of either Castrol RS, Shell Helix Ultra or 0W/40 Mobil 1 and has performed faultlessly. However, more recently I think the top end is a little noisy. At the last service the service chap I spoke to in MB Birmingham advised a slightly thicker oil to cure this. What do you think? Interestingly, in a recent magazine, a well respected M-B independent advised on this very problem, his recommendation being to add a flushing agent prior to oil change as it may be accululation of foreign matter at the top ends of the vee. Whilst I have used flush before, I am a bit hesitant to disturb any foreign matter which could damage the engine. Many thanks in advance for any advice you can offer. All the best, Greg

Certainly a thicker oil will quieten things down and ester based ones achieve this more effectively than other basestocks.

I would try a 5w-40 or 10w-40 ester based ones, theses are still in grade, viscosity wise and will quieten things down.

You can always email me off the boards for prices and guidence towards the best ones.

Cheers
Guy

[opieoilman]

tuxman said:

hi GUY,great topic have enjoyed reading all 9 pages!!last winter i built a ultima can am with a stockish 350 small block chevy ,i have now removed engine ready for a full race engine rebuild strocked to 383 forged crank ,rod and pistons should develop around 500 ish bhp all ultimas run a bit hot so would like to upgrade oil currently run kendle 20w-50 gt1 this is a american oil.block is a 1980 4bolt truck unit with ally heads any advice would be great thanks simon

Use a good thermally stable synthetic oil which will take much higher temperatures than a regular one.

Take a look at the Silkolene and Motul ranges here, there will be something that's perfect for you.

www.opieoils.co.uk/lubricants.htm

Cheers
Guy

[opieoilman]

skinny said:

still here guy skinny said: why not use a 0W-40 instead of a 15W-40. The viscosity when running at operating temp will be (roughly) the same, but at low (start-up) temp, the 0W will be thinner than the 15W (but still a fair bit thicker than either oil at operating temperature) and so circulate easier & quicker ... cheers

Skinny,

Sorry, missed that one!

You can use a 0w instead of a 15w but it depends on what engine you are talking about, new BMW and VAG engines use a 0w-30 which is very thin, but an old design V8 has larger oil ways, so when the 0w thins down when cold it can be too thin, not leaving a good enough film and sometimes even leaking.

Hope this helps.

Cheers

Guy.

[opieoilman]

0w is a much tninner base oil than say 10w and that's the viscosity when cold. Yes oil thins when it gets hot but the polymers contained in the VI Imporvers actually fight back and thicken the oil to the upper number 10w-(40).

Hope this explains

Cheers
Guy

[opieoilman]

optimanc said:

Hi, thats a great service you offer thank you. Here are my details and a few other questions, Make: BMW Model: 320i E36 Year: 1992 Engine size and type: 2.0 straight 6 DOHC Any significant modifications: N/A Brand and viscosity currently used: Castrol GTX Magnitec, 10w-40 My BMW has done over 165,000 miles and occasionally suffers from pre-ignition as well as feeling under powered. I use Wynn’s Octane Booster to try and cover this loss and avoid pre-ignition. I have booked it in for a test however I know any repairs will be sky high! Can you suggest any thing I could try myself to prevent the pre-ignition and loss of power. And is this a good choice of engine oil or should I use a thinner type such as 0w-40 or 5w-40, perhaps different brand i.e. Valvoline? Can the use of engine additives hinder the engine or health? Finally what does the 10w-‘40’ mean in oil viscosity? Many many thanks!

The stock recomendation is for a 5w-40 fully synthetic or a 10w-40 semi.

To combat the loss of power you could use a thinner oil (5w-40) but I would not go any thinner with than that with 165,000 miles as a 0w may well leak and cause problems.

Could be an idea to try a 10w-40 full synthetic as well.

Cheers

Guy.

[opieoilman]

As One said:

Hi Guy, top service - thank you very much in advance Make: Porsche Model: 911 Carrera Year: 1989 Engine size and type: 3,2 l flat 6 Any significant modifications: N/A Brand and viscosity currently used: Mobil 1, 0w-40 176.000 kilometers already, bit smokey at times... Thx, Felix

Felix,

The 0w-40 Mobil 1 is a top quality oil, however the 0w may be a little thin for a car of this age, does it smoke when cold? or sound a little noisy?

I would suggest next oil change look at a 5w-40, it may not sound like a big difference but there is when the oil is cold. When the oil is up to temp a 5w-40 will be the same a the 0w-40.

Cheers

Guy.

[opieoilman]

randos said:

Hi I have a Alfa Romeo 145 Cloverleaf 2.0 16v twinspark The car is a 97 P reg and has 86,000 on the clock, with no mods. I was wondering what the best oil for the car is as i have not had the car long.

The stock recomendation for our beutiful uk climate is a 10w-40, this can be a semi for a full synthetic.

A daily driver and not pushed a good quality semi 10w-40 with frequent oil changes would be fine.

If you wanted the best then a fully synthetic 10w-40 or 10w-50 of PAO/Ester base stock (true synthetic) if you drive an enthusiastic manner.

Hope this helps.

Cheers

Guy.

[opieoilman]

LexSport said:

I've been following this thread for a long time, but finally giving up resisting adding to the list. Volkswagen Golf GTI 16V 1990 1.8 inline 4 DOHC No modifications except a ridiculous exhaust fitted by previous owner which will be getting dumped when I get round to it. I may look at a mild cam and/or a 1.9 overbore in the future. Currently using Quantum Synta 10W40 semi synth from VW or GSF, changing every 5k or so. Going to be flushing through with flushing oil tonight before refilling with the same. At the moment, it's just a daily driver and won't be getting any head work for a while so I thought the 10W40 might be about right as it's not the tightest of engines (145k). Then maybe switching to a thinner fully synth when I get round to rebuilding the head. Any recommendations will be warmly welcomed.

Not much I can add, youve got the idea.

The Quantum is a budget oil made for VAG to use in service centers etc, but if the car is just normall use till a rebuild then there is no point putting in the good stuff. You are using the right grade at the moment however after an engine rebuild a good 5w-40 would be is this as I would go, look for a true synthetic PAO or Ester/PAO base stock, the likes of Motul, Redline, Silkolene and Mobil all do these.

Make sure you run in on a mineral oil after a rebuild.

FLUSHES!!! dont bother, with a regular oil changes the oil has all the deteregents needed to keep the engine clean, for a better flush use a better oil. Flushes can do more harm than good.

Hope this helps a bit.

Cheers

Guy.

[opieoilman]

Rupert,

I am a big fan of the defender.

The recomended grade is for a 10w-40. This can be semi or full synthetic. Many oils out there these days are designed for both petrol and diesel, this is represented by the ACEA A3/B3 on a tin, the A is for petrol and the B for diesel.

Do you mean valvoline? as I have not heard of ovaline.

If it is valvoline, it is ok but much better is available, more of a budget oil and I doubt it would be a true synthetic but a hydrocracked mineral oil (I could be proved wrong). If you want better mpg, then consider a fully synthetic 5w-40, this will give better cold start protection, but are also very fluid helping with the mpg.

I have always recomended not using addatives, but fuel enhancers can be usefull.

Hope this helps.

Cheers

Guy.

[opieoilman]

LexSport said:

Guy, thanks for the info. It's good to know I'm on the right lines. Like Rupert I'm also interested in why you recommend against flushing. I've no idea how often the oil was changed before I got the car 6 months ago and every oil change I've done, even at 5k miles, the outgoing oil has been very black. I thought, perhaps naively, that a good flush out might help things a little.

I am not a fan of flushes due to how harsh they are. Some flushes even contain kerosene

They can do more harm than good by stripping the engine too much of deposits etc. Some people use a flush so it dislodges all the deposits that help keep the engine tigh as it gets older, so the result is it sound rattly and can leak.

Good quality oil use good detergents, and should keep your engine clean enough.

If you fell a flush is needed then use a good oil to do it with.

Cheers

Guy.