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I am having overheating issue with my S10 / 5.3. I am replacing my radiator with a new one and I want to replace the thermostat with a new one as well. I pulled my old one at it says 86/100C. I guess it opens at 212F.
What is 86?
Looking at RockAudot and other places it says stock is 187F.
Will the 187F keep everything little cooler?
Thanks
Waid
Last edited by waid786; 05-13-2019 at 07:12 PM.
Reason: Changed Title
Looks like that one in the pic starts to open at 187 and is full open at 212. (give or take manufacturing tolerances... these things aren't exactly laboratory standard grade instruments)
Looks like that one in the pic starts to open at 187 and is full open at 212. (give or take manufacturing tolerances... these things aren't exactly laboratory standard grade instruments)
Don't outsmart yourself.
I had someone flashed my PCM and enabled the electric fans and he guy set the temperatures for them at 190 and 205. However I am using only 1 fan.
Should I use 190 or 205 setting ?
I am using stock V6 S10 radiator. Should I use 180F Thermostat or even 160F to keep everything cool in my S10 with 5.3?
I am little worries that my single thin SPAL may not be strong enough.
If the radiator and/or fan is inadequate, it won't matter what thermostat you put in it. The engine will simply put heat into the cooling system at a greater rate than the radiator can dissipate it into the outside world, and the temp will climb. If the radiator/fan IS adequate, then the whole system will work just like stock, no matter what shape the sheet metal it's wrapped in.
I'd suggest a stock thermostat and the 205°F setting. With that combo it should go to 205 - 210 and stay there forever. Then if it doesn't stay cool, look at a larger radiator and/or better cooling fan.
If the radiator and/or fan is inadequate, it won't matter what thermostat you put in it. The engine will simply put heat into the cooling system at a greater rate than the radiator can dissipate it into the outside world, and the temp will climb. If the radiator/fan IS adequate, then the whole system will work just like stock, no matter what shape the sheet metal it's wrapped in.
I'd suggest a stock thermostat and the 205°F setting. With that combo it should go to 205 - 210 and stay there forever. Then if it doesn't stay cool, look at a larger radiator and/or better cooling fan.
I put everything back in the truck with stock thermostat and the temperature is climbing to 240F. The both fans kicks in at 205. I noticed that the return or inlet side was cold. I bench tested the stock thermostat it is working fine. After unplugging the fans, the thermostat did open up and inlet got hotter.
I am using a 16" and a 10" SPAL fans.
Is it possible that the fans are keeping the radiator cool enough so that the thermostat does not open since the fan temp setting is too low at 190 or 205?
No I do not think that is possible. The thermostat is on the hot side.
If the return side is cold, that means the fans are doing their job... moving enough air across the rad to bring the water temp down to ambient.
Sounds to me like you most likely need more radiator. It certainly "looks like" you have enough fan. Although before jumping to conclusions, I'd STRONGLY suggest checking the accuracy of whatever gauge you're reading the temps on. Maybe pick up one of those SOOOOOOOPER CHEEEEEEEEEEEEEP infrared units you can get these days; less than $30. Verify what the temp REALLY is before going off on some wild goose chase.
No I do not think that is possible. The thermostat is on the hot side.
If the return side is cold, that means the fans are doing their job... moving enough air across the rad to bring the water temp down to ambient.
Sounds to me like you most likely need more radiator. It certainly "looks like" you have enough fan. Although before jumping to conclusions, I'd STRONGLY suggest checking the accuracy of whatever gauge you're reading the temps on. Maybe pick up one of those SOOOOOOOPER CHEEEEEEEEEEEEEP infrared units you can get these days; less than $30. Verify what the temp REALLY is before going off on some wild goose chase.
One strange twist to my issue.
I had 4.8 for a very short time until it threw a rod. I replaced it with a 5.3 but used the 4.8 PCM and it ran fine with no issues I am pretty sure it never got hot. It seems my issue started when I installed the 5.3 PCM which I got flashed and tuned recently. Maybe its making more power now. I am going to put the 4.8 PCM back in and see what happens.
I am still having over heating problems. It looks like there is no flow at the inlet side of the water pump. The rubber hose still feels cold. The outlet of the water pump is very hot and the over flow tank is getting bubbling boiling coolant. This started just couple of weeks ago. Prior to that, the motor ran fine.
What is tried so far:
1. Tried both 4.8 & 5.3 PCM's and still overheats. Motor is truck is 5.3. Outlet of radiator cold.
2. Installed 160 Thermostat and still overheats. Outlet of radiator cold.
3. Pulled water pump and no obvious obstruction. Impeller looks little rusty. Is this an issue?
4. Blew compressed air in the block and no obvious obstructions.
5. Steam vent tube appears dry and looks like no coolant ever made it to the throttle body. Is this an issue?
6. I used my OBD scanner and it confirmed my gauge readings.
7. Bench tested the stock Thermostat and works fine.
I have another water pump and will try it without thermostat and see what happens and its impeller looks clean.
Do I have some air pocket issue? What else can cause the outlet of the radiator to be cold?
Those fans aren't doing **** without a shroud, you need it to use all the surface area of the rad. you night pull a little bit thru but not enough to be efficient, Look at a stock fbody setup.
Those fans aren't doing **** without a shroud, you need it to use all the surface area of the rad. you night pull a little bit thru but not enough to be efficient, Look at a stock fbody setup.
Fan setup could be better but why is the outlet of the radiator cold even with the fan unplugged?
I tested the Thermostat and work fine and even a new one. The issue started couple of weeks ago. Before it ran fine with single fan.
Rust on the water pump impeller... It's like 100 bucks with a lifetime warranty (Autozone or Advance, etc)
I'd start with a new water pump "just because."
Why do you have coolant going to the TB? Bypass that. It almost sounds like you have a trapped air pocket. Start the truck and run it. Crack open the steam vent ports until you have water coming out. (should be a lot of air that comes out initially.) Then go beat on it. Get it up in the RPM's to move that coolant.
Rust on the water pump impeller... It's like 100 bucks with a lifetime warranty (Autozone or Advance, etc)
I'd start with a new water pump "just because."
Why will do you have coolant going to the TB? Bypass that. It almost sounds like you have a trapped air pocket. Start the truck and run it. Crack open the steam vent ports until you have water coming out. (should be a lot of air that comes out initially.) Then go beat on it. Get it up in the RPM's to move that coolant.
I will do what you suggest. Is the location for the steam port ok?
I am using standard green coolant but I don't that makes a difference.
Waid, is that radiator new? Make sure it’s not got blockages. Easiest way to tell is with engine running and up to temp while your having this issue...feel with your hand on the finned surface of the radiator. You shouldn’t have cool spots. Entire surface of rad should be hot to touch. Had this happen to me with an Altima once and I changed everything on that car first. Car didn’t have enough miles on it to warrant a radiator change, but that was my problem. Hopefully you’ve just got an air pocket.
Waid, is that radiator new? Make sure it’s not got blockages. Easiest way to tell is with engine running and up to temp while your having this issue...feel with your hand on the finned surface of the radiator. You shouldn’t have cool spots. Entire surface of rad should be hot to touch. Had this happen to me with an Altima once and I changed everything on that car first. Car didn’t have enough miles on it to warrant a radiator change, but that was my problem. Hopefully you’ve just got an air pocket.
I bought a brand new radiator. The fans are wired correctly.
When I pulled the coolant line that goes to the throttle body, it was dry like it never seen any coolant and I confirmed that its not blocked. I will add a T to ensure all air is out. I will also add a T on the heater hose to make sure there are is air pocket and the system is burped properly.
I drilled 3/16" holes 3 of them in to the thermostat housing since I have the built in thermostat/coolant outlet type. I put the same water pump and old thermostat back on. I filled it with coolant from the water pump outlet and then from the radiator fill cap until I saw coolant coming out from the steam vent tube. I fired it up and quickly the upper and lower radiator hoses started to warm up. I pulled the steam vent tube off while the engine was running and the coolant was spraying out so I know there is no air trapped. The temperature gauge was rock steady just below 210 event at 80mph.
05-11-2019, 07:03 PM
Stock 5.3 Thermostat 212 F - Over heating? 
Glad it was that easy. 