.... And it's been weeks already. After changing with the red coolant bought from Toyota stearlership on my 02 Toyota Tacoma 4X4. Burping, and check everything but it did not heat up at all. I still have the heat when the heater is on. But after the long drive ( normal temp) the lower radiator is still.... cold? Anything do I need to check ( thermostat is stuck or what, or is anything I need to worry about if I keep driving like that) Truck water temp gauge is still normal ( between H and C) and the truck idle is running fine. Any suggestion, or advise? Thanks

 

I know that my lower radiator hose is almost cold even in the middle of the summer. I think the radiator just does a great job of cooling and that is the way it is.

How does the temp gauge look?
Do you have a scangauge? What does the temp read?