I understand that all or most of the H series blocks share the same oil pump.
This would lead me to assume that they would also share the same oil cooler. (If so equipped)
Now across the range of models equipped with a H series engine; charade, applause, terios etc, I’ve failed to find a factory oil cooler on any parts list. Yet I’ve seen oil coolers fitted on peoples build threads.
Anyone care to shine some light please? 
never known of a factory oil cooler for these mentioned engine’s and not really sure what you mean in the title by “Water-to-Oil Cooler”
Thanks for the quick response.
You know the heat exchanger that is in situ between the oil filter and it’s mounting point? Here’s an image for reference: (From a HC/HD engine manual)
yeh never seen one on any australian delivered H series or never noticed them b4
it was an option known as the “Tropical Pack” from what i could find out, not really a " Factory" option as such more a " Dealer Option". seen a few up here in NQ, blocks with them had a longer screwon part for the oil filter and ran a hard line with banjo bolt from the rhs of block at front, looking from front of car, tapping into the water channels in block, down behind exhaust manifold to this with a then other side goes to a " T " piece in bottom radiator hose from memory.
One of these:
My 1.3 G102 came with one of these. I was able to remove and use it on the 1.5 and 1.6 blocks too.
It fits where the oil filter goes, and is secured in place by a longer tube that the filter then fits into. Water connections are via the block through a steel pipe and banjo fitting, and the other end into the radiator.
I had one G200 with it fitted. very interesting things. most just end up leaking or getting blocked up…
This is what I needed to know! I’ll look up G102 variants now to see what I can find.
Thanks JC
Were you after one J B?
Yup! A working one with no vacuum leaks. Not the end of the world if I can’t find one though.
Local Daihatsu wrecker doesn’t have any and I still can’t find the OEM part number.
I can always add one after the rebuild as it’s in a very accessible place.
@JC050 wehn putting these onto the 1.5 and 1.6 do you then need to use a z386 filter rather then the z443 ?
wondered why applause say to use the z443 (more expensive filter)
Speaking of these.
Just found this whilst pulling my HC-E out of my g100. Forgot about it and had it blocked off.
I have always used the Z443 with the cooler on all my engines.
Are these actually a cooler? I thought they were to warm the water or oil up in colder climates.
No they are a cooler
Just going to revive this thread a bit…
I wonder if you fellas who have an oil cooler attached from factory could tell me the details of your cars?
e.g. G200S HC-E TS MTM EFI 2WD 3D
Would appreciate it very much! 
the one i had was a 1990 G102 HC-E TS EFI 2WD 5D