How to know when thermostat open?

[Blakeo]

Just recently did a timing belt and water pump job on my r33 gtst. At same time I installed a new Nissan 76.5 degree thermostat. It was all installed following Nissan service manual. 

 

I have been bleeding it for over an hour. I filled up with coolant opened bleed screw until coolant come out. Then closed it and started car up with funnel on radiator. Has been running for about hour and a half and coolant in funnel is about 80 degrees Powerfc is showing coolant as 78 degree but the bottom radiator pipe is still cold where the thermostat is. Ive squeezed the pipe to try and help coolant flow through there. 

Is this normal and have I bled it correctly? Is it wrong to say that the car can bleed coolant using the coolant reservior? 

[Ben C34]

 

Top hose is out engine to the rad, which would be hot. Bottom hose is out of radiator, and wouldn't be as hot, I wouldn't say cold though but can't say I have checked.

[Blakeo]

8 hours ago, Ben C34 said:

 

Top hose is out engine to the rad, which would be hot. Bottom hose is out of radiator, and wouldn't be as hot, I wouldn't say cold though but can't say I have checked.

Yes I understand that. But if you trace bottom rad hose up it goes to your thermostat housing. If this hose is still cold yet top hose is at 95 degrees something is wrong? Coolant definitely getting to thermostat no air locks and the jiggle valve is in correct position. 

[djr81]

In the olden days when we wanted to check if a thermostat was opening we would chuck it in a pot of water on the stove.  Turn it on and wait for the thing open. Or not.

[GTSBoy]

Take the thermostat out and replace it with a large washer or other restrictor and run it again. See if it behaves the same when you absolutely know there is coolant flowing.

[Kinkstaah]

I had a very similar situation when idling the car for 30 minutes or so. The car wasn't overheating, but that bottom hose was still ambient temperature.

I took the car for a drive around the block, talking ~1-2min drive around the block, cruising around like a responsible adult, or alternatively, like a guy who wasn't sure if his thermostat was actually working.

Pulled into garage, checked bottom hose, bottom hose was now the temp of the top hose.

The temp sensor for the car (and my aftermarket one) are in the rad top hose, so you will KNOW via gauges overheating if the thermostat truly isn't opening.