G'day guys,

 

I'm wondering how much coolant is in the radiator/cooling system, because I've tried draining the system (using radiator drain plug, and opening the radiator cap) to replace the coolant but I only end up getting maybe 2 litres of fluid once left for about half an hour. Is this about right? I did put the heater on and ran it for maybe 5-10 minutes, I'm wondering if the thermostat didn't open would this be holding back 3 litres. I could try again at another time when I've let the car really warm up properly.

Reading online it says there's meant to be around 6quarts of fluid, which is around 5.5 litres. So I'm not sure what I'm doing wrong here.

 

My car is a L-series 1990 4wd.

Edited March 6, 20179 yr by metalfanmartin

I would raise the front of the car via steep hill,jacks or ramps..so the radiator is higher than the heater core under the dashboard.. most likely you still have air trapped.. open the cap and run it at about 2,000 RPM to get the system to burp by squeezing the top hose a little..

The only way to get all of the coolant out of the engine is to dissasembled it. An oem or high quality aftermarket thermostat has a giggle pin, and does not seal perfectly enough to prevent fluid from draining.

 

If you star the engine after the radiator drains, the water pump is left without water as only what's left in its body is there. Water pumps are bad at moving air. The thermostat will not open, since coolant is not circulating.

 

Running with low coolant is a really bad idea.

There is a bolt on the bottom of each head that is used as a drain hole to get all the water out of the heads one of mine was cloged with stop leak so i had to poke at it with a screw driver to get it to drain its the lowest point on the heads should be easy to find

Tha ks everyone for your replies.

I (naively) never even realised air gaps could be such a thing, and a few things now make sense. When I squeezed the inlet pipe to the radiator it seemed empty, like it only had air in it.

@DaveT - I refilled the radiator anyway, it's definitely not running empty. I'm pretty sure the original thermostat is in there, so I'll have a look when I get time.

If you sharply squeeze the upper radiator hose, you should hear the giggle pin. Also, maybe some gurgles, if there is air in the system. Ideally, there should be no air. It's very important to get any big air pockets out before driving. If everything is working and sealed, small gurgles of air should get less each drive cycle.