Hi Everyone,
I attempted my very first replacement/repair at the weekend, replacing the thermostat on my 2006 2.5L Super Cab XLT Thunder.

It all appears to have gone well, I need to torque the bolts a little more as they appear to be weeping a little, (not sure if that's tears of laughter at my attempted maintenance!). However, I seem to have a problem with circulation as the bottom hose is cold when the top hose is very hot, temp gauge currently normal, although it was very high when I was towing my trailer hence the thermostat swap.
My thinking is that there might be an airlock somewhere as the cab heater is working well, pipes leading into the heater matrix area are hot, just the bottom hose is cold when I think it really should be hot too.

Does anyone have any tips for getting an airlock to shift without a full drain and refill?

Many thanks

Stewart

You have a Ranger which we could never get in North America, 2006 would have a diesel 2.5l engine as well, we are petrol only on this side of the pond

But that being said this is a universal issue
When refilling any cooling system just remove one or both heater hoses at the firewall
Fill the system until coolant is at the hose(s) level then reconnect
The heater hoses let out ALL the air from the engine side of the thermostat, so no question on whether you got all the air out

Radiators on ALL engines are there to dissipate EXTRA heat, depending on the engine and outside temp the radiator may not be used at all during colder months
The engine metal itself with heater going may be all the cooling that is needed

The temp gauge in the cab WILL go high if there is a blockage in the cooling system, for sure, whether its an "air dam" or debris blocking flow

After engine is fully warmed up, shut it off
Move fan shroud back out of the way
Run your bare hand over radiator fins
If should be warmer near the upper hose then get steadily cooler as you get closer to lower hose
Any "cold spots" are blocked passages in the radiator

You can also used a temp gun for the same thing but I like the hands on approach, lol