2002 2.7 tacoma 5speed. 188k miles.

It seems odd to me that the lower radiator hose is always cool to the touch than the upper radiator hose. Is this normal? I keep thinking to myself that either the radiator is clogged or the thermostat is bad. Can anyone verify that this is standard procedure and that the coolant is cooled off that quickly even after driving it an hour at 70 miles/hr. and that everything is normal? I put my hand on the upper hose and it is burning hot and then I reach down to the lower hose and its as if the truck wasn't even running.


EDIT: The temp. needle is always a bit above the middle line, never gets higher or lower than that.

 

The lower hose is the one that carries the coolant into the engine, the upper is your return, so yes, it will be hotter than the lower.

That said, the lower will still be hot, but not as hot as the upper. My guess is you have a thermostat that isn't flowing as well as it should, but that's only my guess.

 

The lower should be warm if the top hose is hot. If it is cold and the truck runs hot, then you have a circulation issue. Thermostat or an air bubble are two likely culprits.

 

If someone thinks about it, after a long drive, touch the radiator hoses and compare the drastic temp. differences and make a note of it. Just seems odd to me that I don't have any overheating issues and the coolant is red as can be with no contamination in it.

 

Do you have a temp gun? Those are the best for things like this. Only about $40 at lowes for a Ryobi gun...