Burping coolant system. Help!

2.7 3rz, I got the engine back together. Got her running finally. Went to burb the coolant to get air out but it seems as if the new thermostat never opened up. Jacked the front end up. Let it idle for a good 45 mins revving it up quite often. Lower hose stayed cool. Never got warm. Bottom of radiator never got warm. New thermostat is a stant and has no jiggle valve. Never used one without a valve before. The thermostat is installed the correct way also. Should I just get a new thermostat or drill a small hole in the one I got? Weird the truck never got to operating temp and thermostat never opened. Feel like there would be air trapped in it somewhere maybe

 

Is there a possibility that the thermostat is installed backwards?

 

No it’s %100 installed correctly

 

Turn your heater control to all the way hot. You might have air trapped in the heater core and lines. Some 3rd Gen 4runners have a rear heater. If 1st Gen Tacomas are the same, turn your rear heater control to all the way hot as well. Like you already tried, have the front end higher than the rear end. A Lisle No-Spill Funnel is a nice tool to have when burping your cooling system. https://amzn.to/2SnrPFV Good luck!

 

I replaced my radiator yesterday on my 3rz, lots of squeezing hoses, turning heater control from hot to cold, let it sit for a while and completely cool. Don’t expect to see coolant rushing by with cap off cuz it’s cored vertically. Do the best you can, fill the overflow fully and drive it. Check it the following morning.... eventually it works it’s way out

 

I’ve turned the heat way up. Tried burping it 3 times now. Letting the truck run an hour at a time. I think I’m gonna have to drill a hole in the thermostat and make my own jiggle valve hole to help it

 

STOP!!! Don't do it unless your engine is overheating. Get the scanner (live data) and check the engine temperature. If it is within limits your system is working perfectly. The bottom of the radiator does not need to be even warm (unless there is a Arizona Noon at the desert hot, you have A/T and drive uphill). The thermostat will open at full blast only if it is very hot and even then the return hose will be warm if your radiator does not work well.

I did complete coolant flush in my truck two years ago (https://www.tacomaworld.com/threads...k-or-rysium-build.457350/page-5#post-17477499). The lower radiator and return hose never got even slightly warm. That is normal for 3RZ if you have MT.

EDIT:
In June last year I replaced a coolant temperature gauge sender and here is the fine details about how the engine temperature is rising from a cold start https://www.tacomaworld.com/threads...k-or-rysium-build.457350/page-8#post-20756897. It was June, and the temperature outside was over 90F. Still lower radiator was cold.

 

I do not believe the thermostat is opening at all to get the air out of the system. I can grab the bottom hose and cannot feel any antifreeze flowing through it. Even after it being started for an hour. The truck never overheated tho. The gauge stayed just a click below half. I do not have a scanner to check then engine temp with. Can you get these at local part stores?

 

The role for thermostat is not open for no reason , but to let the flow of the coolant through the radiator enough to help cooling it if the "internal cooling" can't keep the engine temperature within operating limits. Your temperature gauge indicating "just a click below half" shows the normal operating temperature. If the top of the radiator is hot it indicates that the coolant is flowing. Not oozing, just flowing enough to feed cold coolant from the bottom of the radiator back to the circuit so the engine temperature stays within operating limits. If the thermostat gets wide open it would inject to much cold coolant to the engine and throw the temperature below operating limit.

Believe me, if your engine has air in the coolant it would either burp it out (and you will see the coolant level drop inside the radiator) or would overheat in no time.

 

I’ve just never done a coolant change where I went to burp it and get the air out and not be able too. Maybe I just got lucky this time?

 

Just keep checking the coolant level for the first few weeks and you will be OK.