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.