Cooling ? for FJ40 (1 Viewer)

[rjmcastle]

Have a 73 fj4o running chevy 350 Just replaced my aluminum 4 core radiator(unrepairable) with a 2 core aluminum same dimensions 27.5x19 it always ran between the first 2 marks on stock gauge. Now running right on c mark of guage always had to run 160 thermostat co I need to change to 190? Anyone know what temps the marks on the stock gauge are?

 

[inkpot]

Howdy! I would put in a new 180 or 190 thermostat and see where it goes. Radiator can only run as cool as the stat lets it. See if you need to swap down to 160 next summer. John

 

[mtntravo]

you should put a mechanical gauge on it to see what temp it really running at. i would not trust that 37 year old gauge . im not saying toyota made a bad part but after 37 years things corrode and restistances can change. i would even just hook a tempororary gauge to see what the engine is running at then you will know where that temp is on your oem gauge.

 

[fieldsken1]

Howdy! I would put in a new 180 or 190 thermostat and see where it goes. Radiator can only run as cool as the stat lets it. See if you need to swap down to 160 next summer. John

using a 160 thermostat will just make it run hotter must of the time. the thermostat closes and lets the water in the radiator get cooler by staying in there longer before opening up and letting it go thru the block. if you are hot put a 190 in there it will once again let the water sit in the radiator to get cooler longer


heres a link read.

http://www.google.com/url?sa=t&sour...uYzqAw&usg=AFQjCNG8Z0y8Um_X7deddOx5GrzO0YfjsA

 

[tincherb]

How does water setting in the radiator keep the block cooler? I'm no expert, but a thermostat is just what the article says, a flow regulator. It regulates coolant thru the heat exchanger to maintain a coolant temperature. A cooler thermostat rating will open sooner and longer than a hotter thermostat, keeping the block fluid cooler. Is this wrong?

 

[CheyenneTrucker]

I agree with mr.T, the cooler your thermostate is, the cooler your temp should be.

 

[peterman]

I just changed to a new 4-row core and my 40 is also running at the low tick mark on then C side of normal. Is this a bad thing in anyone's opinion? I was thinking it was actually nice that the engine is running cooler than with the old crust rad, but maybe I'm wrong. Is it somehow better to run hotter? Again, like the original post I am running on the cool side of normal, not just plain cold.

 

[dgangle]

I have a mechanical and the stock gage and the 1/3 line is ~180-190F. maybe different for you.


think you got it backwards cool ken. from your link:

When a thermostat malfunctions it can stick in the closed position not allowing the coolant to circulate, causing the engine to overheat. This will cause the vehicle to overheat in a very short amount of time (about 5 minutes). Or the thermostat could stick open causing the engine to run too cold.

If one has to change thermostats season to season to maintain the correct engine temperature, the capacity of your cooling system is inadequate. Most likely the rad is too small. BTDT

 

[tincherb]

Its my understanding that a cold engine is not optimum. On modern engines, if the engine runs cold the computer detects this and will operate the vehicle in a fuel rich cycle. I can only imagine that a cool engine doesn't combust as well as one at operating temperature, which is why most carb engines have to choke when they are cold. As to your question, you would need to know what temperature your operating as to whether the slightly off cold is a problem.

 

[inkpot]

I have a mechanical and the stock gage and the 1/3 line is ~180-190F. maybe different for you.


think you got it backwards cool ken. from your link:

When a thermostat malfunctions it can stick in the closed position not allowing the coolant to circulate, causing the engine to overheat. This will cause the vehicle to overheat in a very short amount of time (about 5 minutes). Or the thermostat could stick open causing the engine to run too cold.

If one has to change thermostats season to season to maintain the correct engine temperature, the capacity of your cooling system is inadequate. Most likely the rad is too small. BTDT

I agree. That's why I suggested that he watch the summer temps as he went from a 4 core down to a 2 core, which often has less cooling capacity. John

 

[fieldsken1]

I have a mechanical and the stock gage and the 1/3 line is ~180-190F. maybe different for you.


think you got it backwards cool ken. from your link:

When a thermostat malfunctions it can stick in the closed position not allowing the coolant to circulate, causing the engine to overheat. This will cause the vehicle to overheat in a very short amount of time (about 5 minutes). Or the thermostat could stick open causing the engine to run too cold.

If one has to change thermostats season to season to maintain the correct engine temperature, the capacity of your cooling system is inadequate. Most likely the rad is too small. BTDT

well lets see if i got it wrong??? the thermostat stops the flow of water holding it in the radiator to cool down and let the water in the engine to asborb the heat. when the engine water reaches 195 the thermostat opens letting the engine water to go into the radiator and the cooler water that was in the radiator to enter the engine to asborb more heat. while the cooler water enters the engine the thermostat closes so the hot water that entered the radiator has a chance to cool down and the engine water can asborb the heat therefore opening the thermostat repeating the process over again. gee i guess i got it right.. thats how the thermostat regulates the flow. if you use no thermostat the water will just kept flowing not getting enough time in the radiator to get rid of the engine heat..

 

[fieldsken1]

I agree with mr.T, the cooler your thermostate is, the cooler your temp should be.

ALL WRONG on a hotter day a cooler thermostat will make it run hotter

 

[fieldsken1]

read the last sentence.Inside your car's engine, thousands of controlled explosions called combustion events caused by igniting fuel/air mixture inside the engine generate heat. If this heat is not controlled the engine will overheat and internal damage can occur. These high temperatures are controlled with the help of the cooling system. A cooling system consists of a water pump, thermostat, radiator hose, hose clamps, radiator, radiator cap and coolant. The thermostat is designed to control the flow of coolant through the cooling system while the engine is warming up to operating temperature. An engine needs to operate at a particular heat range to be efficient. Once the engine is warm the thermostat will open to allow coolant flow to maintain a particular temperature. Most thermostats are designed to open at about 195° F but other temperatures are available for a variety of applications. A thermostat consists of a main housing, a plunger style of valve with return spring and a temperature sensitive wax filled plunger that acts as the sensing and activating device. A thermostat maintains engine temperature as is opens and closes throughout the engine operation.

.

 

[Splangy]

Ken, you're wrong. The thermostat doesn't close to allow the water in the radiator to cool! When open, it's designed to regulate flow to a slow enough speed to give the coolant enough time to cool in the radiator. It closes because the engine has cooled enough. Once the engine warms up beyond the temperature rating of the thermostat, it opens up again. Pretty simple stuff. You need to reread that link you provided.

 

[fieldsken1]

Ken, you're wrong. The thermostat doesn't close to allow the water in the radiator to cool! When open, it's designed to regulate flow to a slow enough speed to give the coolant enough time to cool in the radiator. It closes because the engine has cooled enough. Once the engine warms up beyond the temperature rating of the thermostat, it opens up again. Pretty simple stuff. You need to reread that link you provided.

the thread above has a paragraph from there read the last line

 

[Splangy]

I don't know how that last line is confusing you, but it is somehow! We all agree that a thermostat maintains engine temperature as it opens and closes throughout the engine operation!


Also, running a lower temp thermostat on a hotter day will NOT increase your engine's temperature. That's just absurd! I think you're confusing it with not running a thermostat at all. Not running a thermostat could cause you're engine to run hotter because it will create an inefficient flow through the radiator (again, because the thermostat is desgined to regulate flow when open.)

the thread above has a paragraph from there read the last line

 

[fieldsken1]

if you run a cooler thermo durning the summer then the thing will always be open as in not there so how will it regulate the flow??? also you say it does not regulate the flow by opening and closing so just how does it regulate the flow

 

[Splangy]

A thermostat is designed to only allow a certain amount of coolant flow through it even when fully open. For example, a fully open thermostat does not allow as much flow as if there was no thermostat there. That's how it regulates flow when open.

In summary, the flow from a fully open thermostat should not be compared to having no thermostat there.

if you run a cooler thermo durning the summer then the thing will always be open as in not there so how will it regulate the flow???

 

[fieldsken1]

never mind i give up you guys are right and i am wrong oh well

 

[dgangle]

they say the first step to recovery is admitting you have a problem