300Tdi cooling problem (no this one is different)

[rover-56]

The running temp on my Def. cab would not go over 70 deg. C no matter what I did. Flat out up hill might get 72. (88 Deg thermostat).
Takes 1/2 hour to reach that temp.

Replaced thermostat (another 88 Deg). both tested ok)
Checked oil thermostat, both cooler lines cool, so I think the oil thermostat is closed.

No change.

Not using the OE temp gauge, that just tells me what it thinks I should be told. (A bit like governments actually:p) Using a digital indicator tested against a mercury thermometer.

So after a bit of head scratching I clamped off the bleed hose coming out of the thermostat housing.

That fixed it. reaches 88 deg in 10 minutes, and runs at the thermostat opening temp.

So my question is does anyone know if there should be some sort of restrictor in this line? It is the one with the 3 way bleed device which is connected to the head tank and the coolant bottle.

Thanks,
Terry

[Don 130]

As far as I know, that union is just a three way joiner. Should be open in all directions. Some greater authority may come along with something to add later.
I'm not clever enough to explain why your cooling system is misbehaving.
Don.

[bee utey]

The "3 way bleed device" is a jet pump to suck air bubbles out of the top of the radiator and flush them to the coolant tank. Its orifice inside the fitting facing the engine should be around 1.5mm. They often block up so someone may have drilled it out. It is a service item, e.g.

Land Rover Defender 300TDI Bleed Hose SET | eBay (http://www.ebay.com.au/itm/Land-Rover-Defender-300TDI-Bleed-Hose-Set-/250965789019?pt=AU_Car_Parts_Accessories&hash=item3a6eba095b)

Yours may be hooked up the wrong way allowing full flow to the radiator instead.

[rover-56]

The "3 way bleed device" is a jet pump to suck air bubbles out of the top of the radiator and flush them to the coolant tank.

Yes that is how I understand its working. It is in the right way according to various pics in the manual. Given its intended operation I know I can't reduce the flow too much. The 1.5 mm number is a good starting point, thanks for that.
I will remove it fairly soon and have a look and maybe replace.

Cheers,
Terry