I had a constant issue with coolant in my Adventra,
Firstly, mine had green coolant when I bought it, and noticed green crystallised coolant in a few places,
And a constant low level of coolant when the cap was removed,
This went on for over 6 months,
I pressure tested in numerous times,
And could smell coolant most of the time and coolant level well below the filler neck always.
I flushed the system multiple time to get rid of the green coolant,
And just used plain water,
And bled the system correctly by reming the bung on the back of the radiator on the RHS.
Figured wasn’t worth putting new coolant in, as it was loosing it still
After pressure testing again,
I found, was the heater tap was weeping at the arm,
removed the tap, then removed the 2 little screws and removed the plate then fitted a very small o-ring, and refitted the plate, That fixed that issue,
Still had the low coolant issue,
Still smell coolant,
Was thinking the heater core was leaking, was so hoping it wasn’t,
I then bypassed the heater core for a couple of weeks, (didn’t need it as it was in summer), but again, still smell coolant,
So back to the start again,
I was convinced the cap was leaking at the housing, and was corroded being still a bit a green crystals around,
Used steel wool to clean the housing,
Cleaned everything again.
I purchased a cap off eBay and they sent wrong one, which was the larger spring loaded one and is a deeper cap,
I then purchase another o-ring cap from Repco, and still didn’t fix it and again still smell coolant, and was low,
I bit the bullet and thought, time to get serious and onto this.
I then went to the wreckers and bought a replacement housing and one to suit the larger spring loaded cap,
Cleaned that up, and replaced the coolant filler housing (had a spare o’ring and gasket from the second chain kit I had)
And that fixed the leaking and low coolant issue.
So I re-connected the heater core,
And the level was holding ok,
After 3 or 4 months, the smell of coolant came back,
But couldn’t see any obvious leaks,
So I then decided to remove the radiator to see if that was leaking,
Sure enough, you could see that the cores at the bottom at the back, (hidden by the radiator fan housing) was split,
I then replaced the radiator,
Bingo, finally fixed the leak and the smell of coolant,
That lasted about 2 months, and started to get the low coolant and smell again,
As you can imagine, I thought WTF !
But this time, the smell was after I had turned engine off,
I noticed water leaking under the can, and figured it was the HVAC/climate control drain,
That’s when I decided to put some red coolant in, so I can locate the leak,
This is when it all come to light !
The water leaking was Not all from the Air/Con drain
The red coolant track was a leak from the large o-ring at the top of the coolant supply pipe at the thermostat housing,
I bought a o-ring kit and replaced that, as I found the old o’ring had gone hard, cracked and perished, possibly the original one.
So that fixed that leak,
Thinking, at last it was the end of the low coolant level,
It lasted about 2 weeks, and was leaking again, going by the red coolant track, but at the back of engine,
Yep, at the thermostat housing,
So decided to attach this from the top,
Removed ALL of the intake manifold hardware, which gave me access to the thermostat housing,
Keeping in mind, this area is done be feel,
And not good if you have gorilla fingers like me.
Used a small mirror to check the area, and notice the red coolant track/leaking from where the heater pipes bolt to the thermostat housing,
The leak was caused by the 2 small o’rings had also perished, again possibly the original o’rings,
Removed the thermostat and cleaned ALL the surfaces, replaced the gasket/s and installing the 2 o’rings,
Re-assembled it all, with working “IN” the engine bay for well over an hour,
I have finally fixed the Coolant leaks, and the low coolant issue.
Sorry about the long banter,
But it was persistence of a process of elimination,
And found, when you fix one leak, it will then leak at the next weakest point.
Edit: there is now no loss, or smell of coolant.
