P0128 code. After 160 temp thermostat.

[ROGELIO A GUZMAN]

Well fellas my XL finally said, nope. I dint like the 160 thermostat you put on me. Lol. Going back to oem Temp thermostat. You guys where spot on telling me this would happens. And maybe, just maybe my XL mpg will improve some. Finally got it to 18-20 in the freeway. Mostly on cruise control.

 

[fasteddy]

That's just a warning code. I run mine with a 160 and it runs much better.
Cooler is better IMHO. With a 160 the coolant should run 175-185
You should see better fuel mileage at lower temps. More timing means less fuel means better mileage (not to start a debate).
The computer automatically retards engine timing the hotter it gets.
Your transmission will last longer from reduced temps, alot longer....not even funny longer.
All subs need a trans cooler, a big one......12x12 derale works good.

You can disable that code with tuning software.
But you can also reset it with a $20 scanner from walmart...it doesn't even need batteries. I have one in my glovebox, always.

Seems expensive (coolant & new therm) to pop a 160 and go back to the 187, just because chevy put in a warning code....its BS. They don't have that code anymore BTW

 

[Mudsport96]

That's just a warning code. I run mine with a 160 and it runs much better.
Cooler is better IMHO. With a 160 the coolant should run 175-185
You should see better fuel mileage at lower temps. More timing means less fuel means better mileage (not to start a debate).
The computer automatically retards engine timing the hotter it gets.

Yes, but unless you get a tune to compensate for the cooler stat, the computer also adds fuel the cooler the engine runs up to a point because its trying to warm the engine. I dont have my laptop at home but in Tunerpro there is a layout that shows how much additional fuel is added up to operating temp. You are better off with the factory temp

 

[fasteddy]

Yes, but unless you get a tune to compensate for the cooler stat, the computer also adds fuel the cooler the engine runs up to a point because its trying to warm the engine. I dont have my laptop at home but in Tunerpro there is a layout that shows how much additional fuel is added up to operating temp. You are better off with the factory temp

Oh...I didn't know that.
All my chevy's run a 160....Palatov, Vette, sub, tahoe.
But I do know that more timing at speed with a lesser throttle position equals better fuel mileage.
My 6.2 sub has a 160 therm, doesn't throw any codes and gets 28-32mpg on the highway, at 75-80mph
The 6.2 with AFM, DOD, VVT and 10 speed is just the most amazing powertrain.
My tahoe with stock 156K mile 5.3, 4L60e, and 3.73 gears gets 17-19 on hwy at 75-80mph
Before the 160, the Tahoe got 15-17 at best. And the trans runs 10-15 degrees cooler because they share the
radiator. Its hard to keep the trans under 200 when the coolant is 205.

 

[Mudsport96]

Oh...I didn't know that.
All my chevy's run a 160....Palatov, Vette, sub, tahoe.
But I do know that more timing at speed with a lesser throttle position equals better fuel mileage.
My 6.2 sub has a 160 therm, doesn't throw any codes and gets 28-32mpg on the highway, at 75-80mph
The 6.2 with AFM, DOD, VVT and 10 speed is just the most amazing powertrain.
My tahoe with stock 156K mile 5.3, 4L60e, and 3.73 gears gets 17-19 on hwy at 75-80mph
Before the 160, the Tahoe got 15-17 at best. And the trans runs 10-15 degrees cooler because they share the
radiator. Its hard to keep the trans under 200 when the coolant is 205.

Hmm. My 06 5.3 4l60e 3.42s gets 18-20 on the Interstate at 75ish with the factory stat. 16 to 18 at 55 to 60 i think its lugging a bit at the lower rpm because of the gearing, but that is a whole different debate.


The 6.2 and 10 speed is a whole nother beast with vastly different programming than the 03 to 06 tahoes. The p59 computer is like Windows 3.1 compared to the i think E78 for the gen 5 engine. So i can't really delve into how it responds to a cooler stat.