LS3 Question
Thread Starter
Intermediate
Joined: Nov 2007
Posts: 29
Likes: 0
LS3 Question
Have an 08 vert with less than 500 miles. Following the breakin period guidelines. However, the engine seems to be running hot, as opposed to my C5; Engine temp 223; Coolant temp: 220. Mild outside weather: 50's & 60's.
I'm concerned because summer weather here can be in upper 90's and lots of traffic backups...extended idle periods.
Is higher operating temps normal for LS3? Will it run cooler when it's broken in?
Call me worried in Texas.
Jim
I'm concerned because summer weather here can be in upper 90's and lots of traffic backups...extended idle periods.
Is higher operating temps normal for LS3? Will it run cooler when it's broken in?
Call me worried in Texas.
Jim
Drifting
Joined: Feb 2005
Posts: 1,567
Likes: 0
From: Clovis, Ca.
You will find the LS3 runs at a higher temperature than the LS2. I took my 08 Z51 (4800 miles) out yesterday for about a 150 mile run and the coolant temp was about 205 all day. A little warmer when I ran the gears at a higher rpm (210 - 215). Outside air temp was in the 50's.
I wouldn't worry right now...just keep an eye on it.
Gene...
I wouldn't worry right now...just keep an eye on it.
Gene...
Le Mans Master
Joined: Oct 1999
Posts: 8,205
Likes: 40
From: Tucson AZ
You will find the LS3 runs at a higher temperature than the LS2. I took my 08 Z51 (4800 miles) out yesterday for about a 150 mile run and the coolant temp was about 205 all day. A little warmer when I ran the gears at a higher rpm (210 - 215). Outside air temp was in the 50's.
I wouldn't worry right now...just keep an eye on it.
Gene...
I wouldn't worry right now...just keep an eye on it.
Gene...
It is normal, but I don't like it either.....
Instructor
Joined: Dec 2007
Posts: 153
Likes: 0
From: Oceanside CA
Yeesh - and it used to bug me how warm my LS2 GTO operated (no low-speed fan until 218*). And the LS3 is even hotter? Zoiks! 
Emissions be damned, I've never had an LSx (this is my fourth LSx car) that didn't do just peachy with a 180* t-stat and reprogramming the fan setpoints. Still, the LS3 is a new engine - anyone know yet how these mills like cooler t-stats?
Emissions be damned, I've never had an LSx (this is my fourth LSx car) that didn't do just peachy with a 180* t-stat and reprogramming the fan setpoints. Still, the LS3 is a new engine - anyone know yet how these mills like cooler t-stats?
Le Mans Master
Joined: Apr 2006
Posts: 5,933
Likes: 13
From: The Beautiful Inland Empire WA.
I noticed (and posted) the same thing when I first got my '08. The LS3 just runs a lot hotter than previous 'Vette engines by nature, and everyone assured me of that. Those temps will also come down a bit with a few more miles.
Do you have the Z51 with an oil cooler? If you do, those temps are a bit higher than what I was told those run......no oil cooler, then you are just fine at those temps.......it IS strange though to see the car running at those high temps......hard for an old muscle car guy to get used to when the old cars used to boil over at those temps....
Do you have the Z51 with an oil cooler? If you do, those temps are a bit higher than what I was told those run......no oil cooler, then you are just fine at those temps.......it IS strange though to see the car running at those high temps......hard for an old muscle car guy to get used to when the old cars used to boil over at those temps....
Intermediate
Joined: Oct 2007
Posts: 26
Likes: 0
How do exhaust mods affect LS3 operating temps?
I realize this question may belong in another area of the forum, but since the topic of operating temperature was raised here, does anyone know how the coolant and oil temps of an LS3 are affected by installing headers (e.g., LG) with high-flow cats? On the one hand, it seems as if reduced restrictions in the exhaust path might help to lower temps (at least on the exhaust side), but I wouldn't be shocked to learn that higher power translates into more heat. It would be interesting to hear from someone with a modded LS3.
Thread Starter
Intermediate
Joined: Nov 2007
Posts: 29
Likes: 0
Thanks
Thanks for the responses. I'll not worry so much now...notice I said so much. I didn't get the Z51 package, so no transmission cooler. I guess I'll find out if it's a problem for sure next summer when sitting in a two mile traffic jam.
Thanks again for your input.
Jim
Thanks again for your input.
Jim
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
Safety Car
Joined: Jul 1999
Posts: 3,559
Likes: 207
From: Olathe KS
My speculation is that it is, as discussed above, designed to run this way, and is accomplished by GM thru elevated temp fan % set points (shifting the entire fan speed curves up, say 5 degrees or so). Also higher hp slightly contributes as well if driven hard (that's elementary thermodynamics).
Perhaps tuners who have compared the two fan programmings curves can chime in on this topic.
Perhaps tuners who have compared the two fan programmings curves can chime in on this topic.
Last edited by bub; Dec 18, 2007 at 01:23 PM.
Instructor
Joined: Mar 2005
Posts: 226
Likes: 0
From: Westchester CA
Unfortunately a lot of us older guys remember the days when you just ran water in your radiator and if it got to 200 we began to panic. So seeing engines that typically run over 200 like the Corvette can be difficult to accept as normal.
However, NASCAR race cars typically are set up to run at 245 degrees because they make more power at that temperature. I don't think I would concern myself about 220 or even 230 degree temps.
Just to clarify a point about a thermostat. Thermostats do not have anything to do with the temperature that your engine runs. A thermostat is designed to allow the engine to heat up faster from a cold start. Once a thermostat reaches its designed temperature it opens up and then the engine will run at whatever temperature it was originally designed to operate at. So putting a 160 or 180 degree thermostat in a new Vette will not lower the car's operating temperature.
However, NASCAR race cars typically are set up to run at 245 degrees because they make more power at that temperature. I don't think I would concern myself about 220 or even 230 degree temps.
Just to clarify a point about a thermostat. Thermostats do not have anything to do with the temperature that your engine runs. A thermostat is designed to allow the engine to heat up faster from a cold start. Once a thermostat reaches its designed temperature it opens up and then the engine will run at whatever temperature it was originally designed to operate at. So putting a 160 or 180 degree thermostat in a new Vette will not lower the car's operating temperature.
Sideways Saturday
Joined: Sep 2004
Posts: 494
Likes: 0
From: Lexington Ky
Unfortunately a lot of us older guys remember the days when you just ran water in your radiator and if it got to 200 we began to panic. So seeing engines that typically run over 200 like the Corvette can be difficult to accept as normal.
However, NASCAR race cars typically are set up to run at 245 degrees because they make more power at that temperature. I don't think I would concern myself about 220 or even 230 degree temps.
Just to clarify a point about a thermostat. Thermostats do not have anything to do with the temperature that your engine runs. A thermostat is designed to allow the engine to heat up faster from a cold start. Once a thermostat reaches its designed temperature it opens up and then the engine will run at whatever temperature it was originally designed to operate at. So putting a 160 or 180 degree thermostat in a new Vette will not lower the car's operating temperature.
However, NASCAR race cars typically are set up to run at 245 degrees because they make more power at that temperature. I don't think I would concern myself about 220 or even 230 degree temps.
Just to clarify a point about a thermostat. Thermostats do not have anything to do with the temperature that your engine runs. A thermostat is designed to allow the engine to heat up faster from a cold start. Once a thermostat reaches its designed temperature it opens up and then the engine will run at whatever temperature it was originally designed to operate at. So putting a 160 or 180 degree thermostat in a new Vette will not lower the car's operating temperature.
3700 miles on my 08 Vert picked up at the NCM 9/20/07. Your temps are very similar to what I see during my daily driving. We had a week of 90+ weather when I picked the car up and the temps were not excessively hot. I did install a Thermally insulated tunnel plate in October but the high temps were already over for the year.
