160 thermo. Heat spike at 107° weather.

[afpj]

whats the highest u seen your temp go up?

Just to clarify, I'm monitoring temp via torque app and OBD2 device. The cluster temp gauge stays at 1 tick below midline (210) until temp goes above 220 using torque, so the cluster temp gauge is not the most accurate.

I think I went to 240 once in stop and go traffic, 117 ambient temperature, but that's when I realized my fan clutch was failing. Like doubeleive, I've hit 225 , but going up grapevine with ac on in summer.

 

[Bill Barnes]

I bought my 2005 Yukon XL 5.3 FF new. It has 204K miles on it now. I watch all of my gauges constantly. Since day one I have never seen my temperature gauge exceed 205 degrees, even when the ambient air temperature has topped 100°. I consider that normal.

 

[George R]

Make sure your fan clutch is OEM/ACDelco, that can make a big difference.

 

[Matthew Jeschke]

@bigdog9191999 I'd like to elaborate on your comment about throwing fueling tables off in PCM. There's a bit more to it. The computer has zero issues fueling at a lower temperature. However, from the factory trucks are tuned to run at higher temps (emissions reasons, carbon buildup, performance of catalectic converters?) that part is above my head.

You get more air and produce more power at a lower temperature, however, it does effect the gas mileage a bit. My C5 Covette is tuned for a 160F thermostat and runs cool. The engine I just finished building for my truck, I kept a factory t-stat in 180F? Don't recall exactly what temp. Truck runs at 210ish tops. No problems so far.

I don't think it will cause any issues what so ever other than maybe a small hit on gas mileage to run at a lower temperature. You don't even really need to adjust the factory tune for the lower temp thermostat other than reprogram cooling fans if you have electric ones.

Here's a screen grab off my tuning run for new engine I built. It's a 6.0L with all the 5.3L cooling stuff, no oil cooler, and smaller radiator for 5.3L (I think 6.0L has a bit larger radiator?). I'm really hammering on the motor to try and hit as much of the load range as possible and it's sticking at around 200F in 100F weather. Running like a top too.

I'd not sweat it if you're not over boiling point. And as for the restrictor, that small line is a relief to revivor if you over pressure right? It bleeds extra air to the tank, then if pressure continues to build, extra coolant out the drain / cap.



PS. One separate note if anybody knows if that's normal for O2 sensors to behave like that let me know.

 

[2591tdj]

So this weekend I went to las Vegas. I had 0 overheating issues in California weather. My Yukon stay well under 200 degree all the time here in Los Angeles weather. So I decided to drive to Hoover dam and it was 107. I did notice my temp go up to 203. Is it because the 160 thermo is not closing and keeps the coolant circulating? I did buy the OEM 187° thermostat last month but haven't installed it. If I swap for the 187 it should keep the coolant longer in the radiator right?

Here’s a screen shot from my last trip to Las Vegas. It must be the norm there.

 

[irwires]

electric fans dont usually turn on till about 210-220. so think about that. and honestly going below about a 180 your not gaining anything and could actually be hurting mileage and such, esp if the pcm isnt tuned for it.


the thermo opens at the temp selected to allow the radiator to keep everything cooled off. once it opens thats as much cooling as you can get. so if your getting too hot then there is an issue with part of the cooling system. pump, rad, fans ect.

 

[irwires]

210 is normal for a tahoe. GM typically uses a 190-195 degree thermostat. This allows the coolant to stay in the radiator long enough to get cooled down otherwise with a lower degree thermostat the coolant just flows thru the radiator with very little cooling and actually cause you to overheat. Many people try a lower thermostat when looking for a overheating problem, some remove the thermostat entirely and then have worse problems. Water boils at 212 degrees, by raising the pressure in the system this temp goes higher. For every 1 LB increase you raise the boiling point 3 degrees so a 15lb cap will raise the boiling point by 45 degrees. 212 plus 45 equals 257 degree boiling point. If you are actually overheating then based on all the new parts you have you need to look elsewhere for a problem. But again 210 is normal and any increase in ambient temp will raise that accordingly.

 

[Fless]

One thing to be aware of is that the boiling point of water decreases by roughly 2°F for every increase of 1,000 ft. of altitude. So near Denver, at about 6,000 ft. AMSL, water boils at around 200°F.

So when you're driving at higher altitudes the boiling point baseline is lower, and the integrity of the cooling system's pressure is all that more important.

 

[Jwedge]

I did away with the mechanical fan three years ago on 2003 Tahoe( right now I have 335k on the truck), had my computer flashed to accept it, and gained HP for doing so. I am moving to a Summitt LM7 long block 450 HP and at that point I will add the electric water pump and a larger core radiator to keep it cool in Georgia dog days.

 

[ROGELIO A GUZMAN]

Just to clarify, I'm monitoring temp via torque app and OBD2 device. The cluster temp gauge stays at 1 tick below midline (210) until temp goes above 220 using torque, so the cluster temp gauge is not the most accurate.

I think I went to 240 once in stop and go traffic, 117 ambient temperature, but that's when I realized my fan clutch was failing. Like doubeleive, I've hit 225 , but going up grapevine with ac on in summer.

I monitor also thru torque app.