In anticipation of summitting the Takaka Hill while towing a trailer of camping gear, I'm doing a bit of maintenance on the Holden's cooling system.
Radiator was recored about 10 years ago, might need doing again. I also pulled the water pump and thermostat. It has a coolant flow to the inlet manifold via a couple of hoses routed from the lower thermostat housing. I pulled these to check them, and found a lot of grungy rusty water, despite all my flushing.
So, here is the lower thermostat housing. The inlet manifold attaches to the two ports on the left of the pic. The top port joins the main flow below the thermostat. The bottom port goes to the channel at the bottom of the housing. Fine and good.
Here is the where the housing attaches to the head. Main flow is fine, into the head. However there is no connection for the channel. WTF. I don't know the history of this motor - it came in a car I wrecked. I'm ass-u-ming that the head is for a different application.
Anyone know if this can be sorted by a bit of drilling? If not I'll just block the lower port somehow and do without the manifold coolant flow.