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When the car is at operating temperature isn't the lower radiator hose going back to the engine supposed to be cool? Mine is just as hot as the upper hose. I installed a new radiator (and previously installed new thermostat & waterpump) because my old one had suddenly developed a couple of holes where the coolant would spray out of. I'm wondering if the coolant is not circulating..would this cause a hot lower hose and enough pressure to make a hole in a radiator? Yet coolant is not dumping into the overflow reservoir. Btw, I've tried with two radiator caps. After being at normal operating temperature for a while there is light smoke coming up from the radiator area (seen this with both old & new).

Any ideas appreciated,
fritz
 

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fritzfry said:
When the car is at operating temperature isn't the lower radiator hose going back to the engine supposed to be cool? Mine is just as hot as the upper hose. I installed a new radiator (and previously installed new thermostat & waterpump) because my old one had suddenly developed a couple of holes where the coolant would spray out of. I'm wondering if the coolant is not circulating..would this cause a hot lower hose and enough pressure to make a hole in a radiator? Yet coolant is not dumping into the overflow reservoir. Btw, I've tried with two radiator caps. After being at normal operating temperature for a while there is light smoke coming up from the radiator area (seen this with both old & new).

Any ideas appreciated,
fritz
make sure you bleed the system. If an air bubble moes to the water pump area, the water pump will "cavitate" meaning that it won't pump anything because of the air surrounding it.
 

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fritzfry said:
When the car is at operating temperature isn't the lower radiator hose going back to the engine supposed to be cool? Mine is just as hot as the upper hose.
The water flows from the upper hose to the thermostat to the engine and out the bottom hose to the radiator. So the upper hose should be cooler than the lower.

The thermostat opens when the coolant temperature from the upper hose reaches the set temperature. So, it will be hot all the time once the engine reaches operating temperature.

How did you measure the temperature?

Lew
 

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Discussion Starter #4
Thanks for quick responses.

I will try again to get the air out.

Lew, I'm sorry I was referring to upper=high & lower=low but yes, the hose from the radiator going back to the t-stat was very hot to the touch (my temperature device :rolleyes: ). But am I understanding right that at normal operating temperature that hose is supposed to be hot and what I am feeling is the coolant at normal operating temp? The temp gauge seems to be staying just below mid-point, i.e. no obvious sign of overheating but I've only driven it for 15-20 minutes since installing the radiator.

thanks
 

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fritzfry said:
Thanks for quick responses.

I will try again to get the air out.

Lew, I'm sorry I was referring to upper=high & lower=low but yes, the hose from the radiator going back to the t-stat was very hot to the touch (my temperature device :rolleyes: ). But am I understanding right that at normal operating temperature that hose is supposed to be hot and what I am feeling is the coolant at normal operating temp? The temp gauge seems to be staying just below mid-point, i.e. no obvious sign of overheating but I've only driven it for 15-20 minutes since installing the radiator.

thanks
What you describe seems normal to me.

Lew
 

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I have an 2004 3.5 altima and im having the problem of no heat unless im accleerating, ive done some research and found that there could be a air pocket, tried lifting the front end up with the rad cap off and bleeding the system. the coolant is not flowing at all in the rad and some slight smoke comes out of it smelling hot. it is topped off and the car stays at normal operating temp. im lost on how to pressurize the system to get the buble out of the pump and get normal operation back. thank you for any input!!
 

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The water flows from the upper hose to the thermostat to the engine and out the bottom hose to the radiator. So the upper hose should be cooler than the lower.

The thermostat opens when the coolant temperature from the upper hose reaches the set temperature. So, it will be hot all the time once the engine reaches operating temperature.

How did you measure the temperature?

Lew
i'm pretty sure coolant gets sucked by the pump FROM the bottom hose, then pushed through the head, and as it heats up and t-stat opens, coolant then gets pushed out TO the upper hose and back to the radiator, so the upper hose will be slightly hotter than the lower hose at normal operating temp. back to the point, the fact that the lower hose is hot/warm indicates that coolant is flowing through the system, properly or otherwise. i'd be more worried if the lower hose didn't get hot after 15-20 minutes of driving.

bfrosty91:
when you say no heat unless accelerating, you mean the heater vents? have you checked the overflow tank? is it full? when you top off the radiator and drive it hard, does the coolant flow to the overflow tank and not getting sucked back into the radiator? could be a bad rad cap, or worse, head gasket leak around a water jacket creating lots of pressure in the cooling system. if it has the symptoms i described, have it tested for combustion gases in the cooling system.
 
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