Thermostat

[turboj91]

Re: Thermostat

The thermostat controls minimum temp. The radiator and fan (among other things) controls max temp.
Changing from a 195 or 180 to a 160 will not change max running temp.
At a cold start, the fan is supposed to be strong and makes alot of noise (air movement),
As the veh warms up, the clutch backs off and the fan slows and so does the air movement.
When the temp rises above a certain level, the clutch comes back in to make the fan move more air to cool things down.
The fan is limited to a certain amount of cfm at idle speeds. Moving down the thru way at 75 pushes more air through the radiator than the fan could ever think of.
Based on your descriptions, something has changed within your system efficiency wise.
Fluid level EXACTLY where it always was?
If you change the thermostat again or remove the one you have, test it in a pot of water on the stove to make sure it opens when it is supposed to. Use a good radiator thermometer. You should be able to take the vehicle for a ride with your laptop and watch the temp come up from cold. With a 160 stat, once it gets to approx 165 (depends where your sensor is) you should see it drop like a rock. The rush of cold water from the rad. will drop the temp. This will happen a few times until all the fluid heat soaks and evens out then the stat will stay open and let the water circulate consistantly. Then it is the radiators job to control actual running temp.
Also go out for a ride with your laptop. When the temp gets to 200+, turn on the heat full blast and watch the temp. If it drops considerably, it is a good indicator that the stat is good but the system has a failure somewhere else. (this test is if you have not already done the above listed test)
If your system is clean (you stated you flushed last year but maybe do it again and see how clean the fluid is) and nothing is blocking the air flow, your water pump may not be moving fluid like it did (a bit of an extreme idea as this issue came on quickly). Look at the flow thru the radiator with the cap removed.
I'd still look at the fluid level.
Other things can generate more heat than usual. Running lean, advanced timing, no egr are the first things that come to mind.
HTHs

 

[vinnieTy]

Re: Thermostat

I just looked over the truck and when i took the radiator cap off this is what i get.....

I did not do a total flush this time i took out about half of the rad fluid to change out the thermostat. I did add some more of the water wetter which maybe i added to much?? Looking in the radiator i see green fluid taking it out this is the color i see,

 

[vinnieTy]

Re: Thermostat

The thermostat controls minimum temp. The radiator and fan (among other things) controls max temp.
Changing from a 195 or 180 to a 160 will not change max running temp.
At a cold start, the fan is supposed to be strong and makes alot of noise (air movement),
As the veh warms up, the clutch backs off and the fan slows and so does the air movement.
When the temp rises above a certain level, the clutch comes back in to make the fan move more air to cool things down.
The fan is limited to a certain amount of cfm at idle speeds. Moving down the thru way at 75 pushes more air through the radiator than the fan could ever think of.
Based on your descriptions, something has changed within your system efficiency wise.
Fluid level EXACTLY where it always was?
If you change the thermostat again or remove the one you have, test it in a pot of water on the stove to make sure it opens when it is supposed to. Use a good radiator thermometer. You should be able to take the vehicle for a ride with your laptop and watch the temp come up from cold. With a 160 stat, once it gets to approx 165 (depends where your sensor is) you should see it drop like a rock. The rush of cold water from the rad. will drop the temp. This will happen a few times until all the fluid heat soaks and evens out then the stat will stay open and let the water circulate consistantly. Then it is the radiators job to control actual running temp.
Also go out for a ride with your laptop. When the temp gets to 200+, turn on the heat full blast and watch the temp. If it drops considerably, it is a good indicator that the stat is good but the system has a failure somewhere else. (this test is if you have not already done the above listed test)
If your system is clean (you stated you flushed last year but maybe do it again and see how clean the fluid is) and nothing is blocking the air flow, your water pump may not be moving fluid like it did (a bit of an extreme idea as this issue came on quickly). Look at the flow thru the radiator with the cap removed.
I'd still look at the fluid level.
Other things can generate more heat than usual. Running lean, advanced timing, no egr are the first things that come to mind.
HTHs

Thanks for the info!!!!!

Well with radiator cap off i can see some water movement so something is going on not drastic but some movement. I turned the heat on as soon as i started the truck becasue i wanted to make sure the antifreeze was flowing through entire system while i top it off. This issue all came after the long drive in the heat. Im wondering if the radiator just had crap in it and i couldnt tell just by looking in from the cap area and it now got loose, just thinking out load right now. The heat is HOT!!
You know what i also have a tranny cooler installed in the front passenger grill area and my tranny temp is even higher then normal. It has to be something with the radiator!!

Anyway thanks for all the info, please make sure it keeps coming!!!

 

[turboj91]

Re: Thermostat

Yuck. I suggest a full system flush to make sure the full system is clean. That stuff on your finger should not be there. The water wetter did not cause this. What type of antifreeze do you use? By the color, I will assume it is NOT Dexcool. I hope it is not (hint).

When you have the cap off and the system is up to temp (stat open) The water level in the tank should be low enough to expose a few rows of tube outlets. The fluid movement out of the tube outlets should almost have the fluid hitting the other side of the tank. It will hit it, but with an arc as it is falling.

With a dirty system, your changes (chip, no egr) may have been just enough to tax the system's efficiency and raise the running temp. Make sure it is clean. Did I mention to make sure the level is full (and obviously without air pockets).

 

[vinnieTy]

Re: Thermostat

I am going to do a complete radiator flush and at that time i want to replace the water pump. I have read AirTex water pump and Edelbrock are good. Any recommendations?

 

[Icarus-54]

Re: Thermostat

Your system maybe trapping air behind the t-stat,drill a 1/8" hole in the face of the stat to let the air out.The is a common problem with cpi motors but I've also seen it in tbi motors.This usually happens after changing the t-stat

 

[vinnieTy]

Re: Thermostat

Your system maybe trapping air behind the t-stat,drill a 1/8" hole in the face of the stat to let the air out.The is a common problem with cpi motors but I've also seen it in tbi motors.This usually happens after changing the t-stat

ICarus - thanks for the info but i changed out the thermostat becasue i saw the truck running hot. The thermostat that was in therre was there for years. I didnt drain the entire system out when i did the thermo replacement becasue i was able to take out just enough fluid that it will be lower then the top radiator hose. Im going to change out the water pump and complete a entire flush.:tup:

 

[SY2455]

Re: Thermostat

Base on all that I read in this posting and looking at the junk that you have in your radiator. You have taken a trip to the radiator zone. Depend on your mileage, you may want to try and get it clean or just put a new one in. I run a 160* Robert Shaw in my truck and it works great even in Feb when I have to smog mine.