4.8 Coolant Replacement
Posted: 17 May 2014 19:09
Guys,
Stumbled across this very useful information (certainly to me).
A while ago I drained the coolant on my4.8 to remove the thermostat housing as it started to show a slow leak where the housing started to corrode. As the coolant was fairly new because I replaced it not to long ago I drained it into a container.
Did the hole job and replaced the original coolant back into the system.
I knew I had an air lock as I was not able to get the amount I drained back in.
I started the engine to circulate the coolant and push the air out.
I continuously felt the hoses to determine when the thermostat open at which point I intended switching off and add water.
After a few minutes, and with the hoses still cold I suddenly realise something is wrong as the electric cooling fan came on. I immediately shut down the engine and could feel the block was warm but still no water flowing.
The heat of the block eventually conducted to the thermostat housing and eventually heated the thermostat to open enough to get the trapped air through.
Yes, while it was out I did check the small check valve and that was operating and perfect.
Well I stumbled across the following coolant bleed valve which I am convinced would have prevented the close call with great expenses.
Remove the plastic engine cover ( four 10mm screws) to expose the engine.
The read circle and yellow arrow indicate the bleed valve which according to the manual should be removed for draining the fluid and keep it open when refilling and only close when the water start to come out the bleed valve.
I will definitely follow this closely next time.
I am sure this would make the worlds difference and hope this could save someone else's bacon.
Bruin Beer
Stumbled across this very useful information (certainly to me).
A while ago I drained the coolant on my4.8 to remove the thermostat housing as it started to show a slow leak where the housing started to corrode. As the coolant was fairly new because I replaced it not to long ago I drained it into a container.
Did the hole job and replaced the original coolant back into the system.
I knew I had an air lock as I was not able to get the amount I drained back in.
I started the engine to circulate the coolant and push the air out.
I continuously felt the hoses to determine when the thermostat open at which point I intended switching off and add water.
After a few minutes, and with the hoses still cold I suddenly realise something is wrong as the electric cooling fan came on. I immediately shut down the engine and could feel the block was warm but still no water flowing.
The heat of the block eventually conducted to the thermostat housing and eventually heated the thermostat to open enough to get the trapped air through.
Yes, while it was out I did check the small check valve and that was operating and perfect.
Well I stumbled across the following coolant bleed valve which I am convinced would have prevented the close call with great expenses.
Drawing1s.pdf- Wide angle
- (495.25 KiB) Downloaded 1421 times
- Drawing2s.pdf
- closeup
- (357.67 KiB) Downloaded 1103 times
The read circle and yellow arrow indicate the bleed valve which according to the manual should be removed for draining the fluid and keep it open when refilling and only close when the water start to come out the bleed valve.
I will definitely follow this closely next time.
I am sure this would make the worlds difference and hope this could save someone else's bacon.
Bruin Beer
