phootbag

The flow of coolant is; From the thermostat housing, through the lower hose, up the radiator, into the upper radiator hose and into the cylinder head. The upper hose will warm up faster than the lower hose because the upper hose is near the cylinder head which always has coolant circulating and the lower hose is downstream of the thermostat which is closed until it warms up.

You can monitor the temperature of the thermostat housing behind the thermostat and compare that to the temp of the lower radiator hose just after the thermostat housing. This will show a temperature difference as the car warms up from a cold-start. When the thermostat housing reaches around 190-200 degrees the thermostat should open up, you should see the temperature of the lower hose begin to rise as the hot coolant flows through. This is how to make sure the thermostat opens and at what temperature it is opening up at.

You should be able to remove the cap, DON'T BURN YOURSELF, and rev the engine and watch coolant rise up...

phootbag

... and flow a bit from the hole. Though, it may be only very slight and possibly not much at all because the coolant travels UP through the radiator, this causes the flow to be disperse and pretty mellow.

If the car warms up normally, you can confirm the thermostat opens as I mentioned, the water pump is probably pumping coolant as it should.

HonBeer

DO Not hijack a thread! Start your own or just read one that already available.

grhawn

Thanks for chiming in on the attempted thread hi-Jack guys. The other day when I was troubleshooting the car I took the radiator cap off - car wasn't quite fully cooled down but not scalding hot. I attempted to start the car with the radiator cap off - fluid gushed out of the hole while turning the car over, and bubbled out while idling for a few seconds. I was expecting to be able to see it flow, but this wasn't the case, and this was after I bled the system.