Air lock in cooling system

[Goatmaster]

Hi All
Just replaced the 82degC thermostat for a 87 as temp guage would never go past a third and was usually at 1/4. Running veg so engine much happier if running temp that bit warmer. However I am not sure if I have now managed to form an air lock. Is there a foolproof way of checking and correcting/bleeding?

I have got the temp up to halfway on the gauge so hopefully opened up the new thermostat but it now takes a very long time before it gets there. Far longer than I would have expected.

 

[Goatmaster]

After a few hard drives it seems I cannot get the temp gauge above the little white dot on the right near the base of the needle. I am presuming that this is the register mark for correct running temp and as such indicates that the thermostat is opening as it should and that all is well. To be on the safe side I very carefully cracked open the radiator top cap a few times to relieve the pressure in the top hose and managed to expelled a little air, although very little. The bottom radiator hose however is still cool so very little coolant seems to be passing through the rad. It seems unbelievable that the engine is cooling so well without the rad. I do however have the heater fully on but with no fan, so that any air in the heater matrix is encouraged out.

 

[Goatmaster]

Marked improvement in performance so well worth it.

 

[solarman216]

The only time you would expect the bottom hose to be hot is after a long run up hill towing a heavy trailer, Rick

 

[elty001]

Bleeding the air from the system is really simple.
Get the front end higher than the rear to start with.
Make sure heater control is set to hot to let the coolant flow through the heater matrix.
Remove radiator cap and start the engine.
Let it idle up to temp keeping an eye on the coolant level in the radiator and top up if needed.
If any air is in the system you will see the bubbles in the top of the radiator.
Once you are happy replace the radiator cap,top up the expansion tank and take it for a spin.
Once cool after a run check the level in the radiator:thumb2

 

[Goatmaster]

Thank you both for the replies. All seems to be OK now but I will check for any more air in the system again over the weekend, just to make certain.

At what temperature does the electric fan start up and is it possible to test the fan by bridging contacts? I am guessing the temp sensor is one of the two in the thermostat housing?

 

[solarman216]

Thank you both for the replies. All seems to be OK now but I will check for any more air in the system again over the weekend, just to make certain.

At what temperature does the electric fan start up and is it possible to test the fan by bridging contacts? I am guessing the temp sensor is one of the two in the thermostat housing?

If you have an electric fan it will be for the AC if it is standard, if someone has added it as an extra who knows how they have wired it, Rick