Strange Extra Thermostat 4jg2

[Mel31]

Finally got our rebuilt engine back into our bighorn. Tidying up a few leaks caused by the engine pressurising thanks to the cracked head. We have come across this extra thermostat in the cooling system. It came out of the pipe that goes behind the engine from the passengers side to the drivers side. Anyone have any ideas what it's for, do we need it? Ours has a ruddy great hike in it that was leaking.

[geeves]

It controls the water supply to the oil cooler in the oil filter housing. What it does is mystery but my guess is that it does not let water flow till the engine has warmed up This would warm the oil quicker so more economical.

[Mel31]

Cheers for that. It's been taken out now and the bubbling in the radiator has stopped! Got a bit worried there when it was still doing it after a new head and a total rebuild! Must have been sucking air through the hole in it. You can see the water moving through the radiator now where before it was stationary and bubbling.

[geeves]

That wont of been the cause. There are so many places air gets trapped in these settups and you have to run it for a while with heater on etc to get rid of those bubbles. Mine took a litre of coolant after the first run but then fine

[Angusmeads]

Does anyone have a part number for that thermostat.
And what way around does it go

[geeves]

Vehicles like ours I would bypass it

[turnturn]

Oil Cooler Thermostat.
Part Number 5-21770-001-1