AIR LOCK REMOVAL / HEATER WARM AIR
You need to find whether it is an 82 degree or an 88 degree thermostat fitted and if it is working ok or even if a thermostat is fitted .
But , before you remove the thermostat housing , it would be better to get a couple of thermostat housing gaskets first .
Check that the thermostat is opening at the correct temperature by inserting it into a suitable pot etc and fully covering it water .
Heat the water till the thermostat opens , checking as you heat the water up , using a cooks thermometer , or an infrared thermometer , or any other suitable temperature detector .
When refitting take great care not to catch the edge of the thermostat housing on the side of the rocker cover .
Tighten the bolts down fully finger tight before tightening but do not over tighten .
Query
The core plug has been fitted and the cooling system has been filled, but the pipe going into the heater matrix is warm but the one coming from the heater tap is not very warm and no heat appears from the vents at the screen.
With the engine switched OFF ,
Assuming that the heater matrix and the engine waterways are clean and both in good working order then the following procedure might help prevent / clear an air lock.
This method is better with two people but can be done by one person . {The second person is only there to give you the finger on your matrix end }
Cover the coil area with a poly bag to protect from spillage
With all hoses on as per normal .
Remove radiator cap .
Fill through radiator till full.
Replace radiator cap.
Disconnect hose from heater matrix to water pump only at matrix end
Leave heater matrix end without hose on it .
Now start to fill slowly through the heater hose
Continue to fill SLOWLY through hose end until water pours CONTINUALLY from heater matrix { first water will be followed by air then water }
You can use a cloth to soak up water as it comes out .
When water continuous from heater shove a finger over the open pipe end at matrix and fill hose to the top .
Reconnect hose smartly to heater
TIGHTEN ALL HOSE CONNECTIONS
Start engine .
Warm up slowly to full temp
BEWARE THE ROTATING FAN BLADE then
Check the temperature of the hoses where they go into the heater matrix and if cooler than the hose part further down then do the following.
When warm , squeeze the hose near the top { heater to the water pump } flat with your hands for a few seconds to cut off the flow from the heater to the water pump then release very quickly .
Do this two or three times and this should hopefully get rid of the air lock .
The unwanted air will go into the radiator .
When working OK you will feel the water pulsating through the hose and a noticeable difference in the temperature
I personally think this is how Reliant engines should be filled every first fill { unless you are lucky }
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