Engine oil spec

Just wanted to ask a couple of questions as I'll be servicing shortly

I have a 2006 Jimny hard top.
How do I know which engine I have?

Looking at the oil spec, on the Wiki, on the latest engine that I'm assuming mine has, it says 10w-30 (good) or 5w-30 (off road)
What are you mostly using in yours, for mainly road use, with a bit of mild offroading thrown in?

Just been through my stash of oils, and I'd have expected to see at least a part container of 10w-30, as I've had 3 previous Jimny's, but all I seem to have around, is lots of 5w-30 containers

THanks in advance

Climate affects what viscosity you should use more than what you're using it for, assuming your engine is in good condition. Some people like to use "heavier" oil in older engines to keep the oil pressure up with looser clearances, but at that point you're just delaying the inevitable. 
I have always used good quality fully synthetic 5-30, the climate where I am is very temperate, never snows but often does freeze over night in winter. If you have a vvt engine, best to stick with what your manual reccomends as the vvt cam phaser works off oil pressure. 
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The manual gives a wide variation of acceptable viscosities.  I put 5W30 in the gen3.

Hi
Thanks for that
Due to the high number of 5w-30 containers I have kicking around, I think I must have used that previously too in other gen 3's

This engine is pretty low mileage (65k) and is almost silent on tickover. Quietist engine I've ever heard (or not heard), so I hope 5w-30 will be ok 

In the U.K. there will be no difference between 5w/30 and 10w/30 as the ambient temperature doesn’t get cold enough to the point where it makes a difference.

If the temperature got down to -15C or below then 5w/30 would be better as it will be less thick at the low temperature. However, at 0C or just below there will be no difference.

Perhaps more importantly the upper figure of 30 could cause some concern if ambient temperature goes over 35C, the oil might be too thin.

The general advice is to use the grade specified in the handbook and a grade either side will make no difference at all unless you are pushing the temperature boundary.

10w/30 is the one specified, but if you really wanted to depart go for 5w/40. Perhaps more important is to use normal, semi or fully synthetic oil depending on which is recommended, but don’t mix these.

Robin

The figure before the W is the SAE viscosity at 0 deg C.  It certainly gets that cold where I am.

Just tells at what temp the test have been done, not at what temp the oil is suitable for, or a max / min.

Gets -15 here but ordinary oil is ok.

The m16 is speced for 0w-20 but i have in my limited wisdom assumed it was the same engine as the m13 so been using the 10w 30 oil. Even in winter. Or was it 5w40..?

rogerzilla wrote:

The figure before the W is the SAE viscosity at 0 deg C.  It certainly gets that cold where I am.

Not true, the figure before the W is considered to be a winter grade and the SAE measure this at a temperature between -15 and -40C depending on the grade, see en.wikipedia.org/wiki/SAE_J300.

The chart shown in this link (penriteoil.com.au/knowledge-centre/Visco...an-sae-viscosity/180) is probably as good as you can find and shows 5w30 as suitable between -30 to 36C and 10w30 as suitable for -25 to 36C, both equally as good for any temperatures we see in winter in the U.K.

However, recent high summer temperatures would suggest 5w40 as more suitable going from -30 to 40C.

Robin

 

I thought 0 deg C was in the standard textbook for vehicle mechanics (Hillier) but, checking, that actually just says the W viscosity is at a "sub-zero" temperature, so the author probably couldn't be bothered to look it up!

One advantage of 0W oil is that it should indicate a proper Group IV (PAO) base oil, as it's hard to make a hydrocracked "synthetic" mineral oil meet  that winter rating.  Synthetic *should* mean the base oil has been created by combining smaller molecules to give the exact desired properties, but a legal case in the USA many years ago means any old mineral oil can be labelled "synthetic" after what is often superficial processing.  You can't make a proper synthetic oil and sell it for £20 for 5 litres, as is the case for some of the off-brand stuff in the discount stores.

Not that a gen3 Jimny needs anything better than a good quality 5W30.

rogerzilla wrote:

I thought 0 deg C was in the standard textbook for vehicle mechanics (Hillier) but, checking, that actually just says the W viscosity is at a "sub-zero" temperature, so the author probably couldn't be bothered to look it up!


 

A number of Internet sources, including oil manufacturer's suggest the test is done at 0F (-17.8C), the US ones I can understand saying this, but the high temperature is done at 100C which is 212F, so a nice mix of units if that is actually true.

Anyway 5w/30, 10w/30 or 5w/40 won't make any difference in the UK.  The Jimny is not a high stress engine, so almost anything will do.  I can remember my old motorcycle days, the Hondas I had used a mono grade oil, but my '77 Triumph is like the Jimny, you can put anything in it.

My other car uses a fully synthetic oil and if you read the manual it only specifies one make, which of course is twice as much as anything else.  As I don't do many miles my local garage usually only changes the oil every second year, there is no point changing every year it comes out as clean as it went in.

Robin

I would guess the incredibly thin 0W16 oil in the gen4 is just there to scrape a few tenths more mpg in the WLTP test.  Certainly, if you read the owner's manual, you can use other grades depending on the climate.  I doubt I'll use 0W16 when I come to change it myself.

Thanks for the input chaps