TOYS4TOTS

CAUTION FIRST POST!!!!!

Yes this is my first post on this forum. I have been reading for hours and can't find answers. Maybe someone can help here.

2001 Taco V6

Top radiator hose very hot, bottom hose cold. I have gone through 3 thermostats and had the same results. Just had it at the dealer and they put in a new thermo and still the same results. New water pump and timing belt. I can not tell if everything is OK. Dealer said it should be fine. I just don't understand how the bottom hose can be so cold when the top is too hot to touch. I have never overheated so I am lost. An interesting twist is that I saw coolant on the floor the other day. I have been told its not the head gasket as the truck passed pressure tests warm and cold. I have been told by others that it is the bypass line under the intake where it goes in the block. You can see where the coolant ran down the back of the block and dried up and now its crusty. I know thats alot to digest but any help?

thanks

oly884

The top SHOULD be hot, and the bottom SHOULD be cold.

The top hose is the return from the engine, meaning that the coolant flowing through that tube picked up the heat from the engine block. As air goes through the radiator the heat is exchanged with the air and the temperature of the coolant lowers. Since there is a overall flow of the system, the coolant continues its way down towards the bottom of the radiator, becoming more cooled as it travels. This is until it reaches the bottom hose where, it should be cool, so that when the coolant is put back into the engine block it can absorb more heat from the combustion process.

oly884

Here's a good link that goes into detail more http://auto.howstuffworks.com/cooling-system.htm

TOYS4TOTS

Good link, but it just doesn't seem right. I guess the cooling system is working real well then. I always thought the bottom hose would be warm to the touch. Mine is cold. I follow it up to the side of the block and where the thermo housing is on the block its hot. I guess this is correct then. Just not used to something working that well. Anyone else on the other issues with the coolant?

oly884

Yeah, if you're not overheating, and never have, then you're doing just fine.

w99t4rweos

What does your temp gauge show when it is fully warmed up? Is it in the normal range? Does it ever go higher range?

If there is a t-stat or radiator problem is usually causes a flow restriction of coolant . Which will show on your temp gauge as higher than normal temp.

TOYS4TOTS

Temp has never moved from dead center.

Where is the temp sending unit located on this motor?

oly884

If your temp has not ever moved from dead center, then the cooling system is doing its job. Don't bother with it anymore unless you want it to not work.

MTL_4runner

You'll see it is normal (esp in winter months) and I went through the same thing:
https://www.yotatech.com/forums/f2/those-cold-climates-hows-your-heat-74448/