Coolant level dropping

Hello all, first time I have had a problem with my 2019 Gen 4 Jimny but a couple of weeks ago I noticed the coolant level was lower than I remembered, checked again today and the level is definately dropping, in the expansion tank its now just above the lowest of the three level markings. Have spent considerable time looking but cannot see any obvious leak. Have checked the oil both on dipstick and under filler cap and it looks perfect, no sign of mayonaise or anything to suggest water is getting into the oil. Heater works perfectly, car runs  and starts perfectly as always. Any ideas on where to look for a leak on a gen 4? Have not noticed anything under the car, but she is outside and the ground is seldom dry. To top up would I have to use Suzukis Blue coolant or can another be used to top up with  until I can trace the leak. Would the leak be possibly detectable with UV light from a torch?

Many thanks
 

Check it's dropping first. Should stay much the same for at least a month, but always check with a cold engine as the level moves with expansion.

Haven't seen any reports on the G4, so based on the G3 and in theory they can leak anywhere.
Common leaks are:
Have a good look around all the hose fittings, especially the top and bottom radiator hoses.If you can't see anything try again but use paper kitchen towel to have a wipe around and under the bits you can't see. Its easy to see if it soaks up any water, if it does dry the area and try again after a drive to confirm. Check the engine sides and under the water pump, have a wipe around with the paper towel if you can't see. 
Look from under the vehicle if you can, it's surprising how water leaks show up better from underneath as gravity puddles the coolant.
If you can take the plugs out have a look at the colour of them. They should all look similar, if one is obviously cleaner than the others it may be worth using a combustion check kit on the cooling system, cheap enough on eBay etc.
An overnight pressure test may also help, but most don't have the kit to do this so maybe time for a garage. I assume it's not in warranty? If it is take it back to Suzuki and let them do the work. 

As for top up you could find out what it uses (sorry no spec for G4), colour is not always sign of compatibility. Prestone coolant is universal and they claim can be mixed with all types, I've seen nothing to undermine this claim. 

 

Thank you Scimike, much appreciated, the coolant specified is Suzuki LLC Super Blue which appears to be an Ethylene Glycol non-silicate type. The manual warns about using different types of base coolants, unsure what 'base' means. The level is definitely dropping, its only a few mm in the plastic expansion tank after 300 miles or so but its now near the lower level so need to top up soon.
I'll certainly have a look from underneath as soon as its dry and try the paper towel to see if that detects anything. I have also noted your advice to check the plugs etc but hopefully as the car has only done 21K miles and has had every service done on time by a Suzuki dealer and has never been abused nothing serious will show up. Is there a way to easily get to the heater matrix and its feeds to check around that?

It's possible the heater matrix may smell of antifreeze if it's leaking as it warms up. It's also possible your carpet could be damp, but very difficult to prove this time of year unfortunately. They are historically very difficult to get at, can't see the G4 being any different.

Interesting that the antifreeze is reported as ethylene glycol, that tends to be the older "classic" antifreeze. Propylene glycol tends to be the modern stuff as it's a low  toxicity,  ethylene glycol is poisonous. That's the base they are referencing.

Halfords or a good local auto shop should be able to provide this, it's nothing special. LL is a reference to Long Life, usually 5 years as opposed to 2 years for none LL. 
 

Thank you Scimike, appreciated, your explanation makes perfect sense, can call at Halfords tomorrow to hopefully get something to top up with. Have double checked and the owners manual definitely states ethylene glycol. I can smell something inside the car but unsure if its just washer fluid or coolant, the carpets are bone dry so I am hoping the leak is in the engine bay rather than the Jimnys interior. I'm much more used to older cars and although the Jimny is relatively simple compared to many others its still a lot more complicated than the old stuff I was brought up with and am used to fixing...I still worry about not having a starting handle.

Also a leak could be from such a tiny pin prick hole, it doesn't leak when the system is cold and only when pressure builds  up as the system gets up to temperature. 
It could also be leakingp as steam rather than a drip, dribble or squirt of coolant.

Thank you Soeley, much appreciated. I have a feeling you may be correct and that its going to prove to be a pinprick type leak that is going to be both difficult to find and sadly very expensive to fix. I have checked to see if I can see anything whilst she is hot as soon as I get home after a run but so far to no avail. I'll post here if I make any progress in finding the leak but if anyone has any ideas on tracing it I would be very grateful if they would share their thoughts.

Hi AJ,
Must admit your comment about using UV made me look and yes, you can find the leak with a UV system.
Not that expensive and easy to obtain fluid / kits on the net.
One such kit
Check this out! amzn.eu/d/eDV059c

Got to be worth a shot if you can't see the leak.Best check engine first with UV light just in case it's covered with invisible messages from Suzuki !

Is it worth just changing the radiator cap ?

Thanks again Scimike, very much appreciated. I have a couple of UV torches on order for different projects that will hopefully arrive tomorrow so I will then, hopefully, be able to scan the engine bay to see whats there, clean up if needed and then wait to see if anything new appears. I think the coolant contains Fluorescein, the stuff I got to top up with certainly does, so even if it dries on it should show up under a UV light source if any is escaping from the system. Thank you for the link will keep that noted if I need it, may help someone else in the future too. Thanks again for your help.

Thank you for your suggestion DJ20, very much appreciated, now I have topped the system up will keep the cap in mind if I cannot find an obvious leak elsewhere, would be wonderful if its something as simple as that. Many thanks.