160 thermostat
Thread Starter
Safety Car
Joined: Jan 2006
Posts: 3,940
Likes: 42
From: shavertown Pa.
160 thermostat
HI: I have put a 160 stat in my z06. and temp is at 170 highway. 20 to 30 drop in temp,( no difference like factory stat if you just let it idle )but that drop in temp,will add a little life of your engine. also when you refill your cooling system remove the bleed pipe from the right hand side of the radiator, as your filling the air pushes out, A LITTLE COOLER IS BETTER....
Team Owner
Joined: Mar 2001
Posts: 21,325
Likes: 3,841
From: small town in S.E Pa. PA
St. Jude Donor '03-'04
Originally Posted by bob guzzy
HI: I have put a 160 stat in my z06. and temp is at 170 highway. 20 to 30 drop in temp,( no difference like factory stat if you just let it idle )but that drop in temp,will add a little life of your engine. also when you refill your cooling system remove the bleed pipe from the right hand side of the radiator, as your filling the air pushes out, A LITTLE COOLER IS BETTER....
once the stat is open be it 160 or 190, heat will rise in the engine just as fast as it did before.... setting your fans to a lower temp will help keep coolant at a lower temp under 35 mph... after 35 mph the fans shut off. with the ac on the fans will cycle on and depending on ac head pressure.
Intermediate
Joined: Jan 2006
Posts: 30
Likes: 0
From: Garden Grove California
Evil Twin is correct. Running these motors too cold is much harder on them then running them at the higher factory default settings. As I hear it, the pistons and rings expand at a different temps then the cylinder walls do. At factory temps or close to Factory temps the clearances betweent he piston/rings/cylinders are just about optimal for compression and minimal friction. If you go too cold this causes an condition where there is way to much friction occuring, thus the engine wears out prematurely.
.......The 190* is a much safer bet.
Just my .02
.......The 190* is a much safer bet.
Just my .02
Safety Car
Joined: May 2000
Posts: 4,820
Likes: 347
From: Albuquerque NM
Do you really think that the pistons and rings (which are not exposed to coolant) will be at a different temp from runnig the coolant slightly cooler? Come on, they are operating in an enviromment of burning combustion gases, one THOUSAND to two THOUSAND degrees, so 20 degrees cooler coolant (most folks see 170 coolant temp when running a 160 stat) is gonna cause massive increases in friction???????
That theory is BS and the facts don't support it. IF running the engine 20 degrees cooler made more frictional losses the dyno would show less horsepower than running it hotter. That AIN'T the case. ALL the LSX engnes I have dyno'd or seen dyno'd made more HP when they ran a little cooler.
If the friction went up that fast with cooler temps, consider what it would be on a cold December morning, on a cold start. Your starter could not even crank the motor. The facts are tolerances don't change that much AND we run 5w-30 oil which provides a barrier between metal to metal contact to minimize friction. It does this just as well with the engine coolant at 170 as it does at 190.
GM runs these engines hotter than optimal to decrease emissions.
Pure. and. Simple.
That theory is BS and the facts don't support it. IF running the engine 20 degrees cooler made more frictional losses the dyno would show less horsepower than running it hotter. That AIN'T the case. ALL the LSX engnes I have dyno'd or seen dyno'd made more HP when they ran a little cooler.
If the friction went up that fast with cooler temps, consider what it would be on a cold December morning, on a cold start. Your starter could not even crank the motor. The facts are tolerances don't change that much AND we run 5w-30 oil which provides a barrier between metal to metal contact to minimize friction. It does this just as well with the engine coolant at 170 as it does at 190.
GM runs these engines hotter than optimal to decrease emissions.
Pure. and. Simple.
Team Owner
Joined: Mar 2001
Posts: 21,325
Likes: 3,841
From: small town in S.E Pa. PA
St. Jude Donor '03-'04
Originally Posted by 6Speeder
Do you really think that the pistons and rings (which are not exposed to coolant) will be at a different temp from runnig the coolant slightly cooler? Come on, they are operating in an enviromment of burning combustion gases, one THOUSAND to two THOUSAND degrees, so 20 degrees cooler coolant (most folks see 170 coolant temp when running a 160 stat) is gonna cause massive increases in friction???????
That theory is BS and the facts don't support it. IF running the engine 20 degrees cooler made more frictional losses the dyno would show less horsepower than running it hotter. That AIN'T the case. ALL the LSX engnes I have dyno'd or seen dyno'd made more HP when they ran a little cooler.
If the friction went up that fast with cooler temps, consider what it would be on a cold December morning, on a cold start. Your starter could not even crank the motor. The facts are tolerances don't change that much AND we run 5w-30 oil which provides a barrier between metal to metal contact to minimize friction. It does this just as well with the engine coolant at 170 as it does at 190.
GM runs these engines hotter than optimal to decrease emissions.
Pure. and. Simple.
That theory is BS and the facts don't support it. IF running the engine 20 degrees cooler made more frictional losses the dyno would show less horsepower than running it hotter. That AIN'T the case. ALL the LSX engnes I have dyno'd or seen dyno'd made more HP when they ran a little cooler.
If the friction went up that fast with cooler temps, consider what it would be on a cold December morning, on a cold start. Your starter could not even crank the motor. The facts are tolerances don't change that much AND we run 5w-30 oil which provides a barrier between metal to metal contact to minimize friction. It does this just as well with the engine coolant at 170 as it does at 190.
GM runs these engines hotter than optimal to decrease emissions.
Pure. and. Simple.
Bill aka ET
40 years of automotive engineering
15 of them with GM and the last seven with the C5 engineering team.
retired 2001
Instructor
Joined: Aug 2003
Posts: 220
Likes: 8
From: A little place called Macungie PA
I normally stay out of it...
But, besides ET's engineering knowledge ( which should not be discounted) just step back and take a look at the system.... The Rings are in constant contact with the cylindar walls. The cylindar walls have coolant flowing behind them which is attempting to keep the engine at a constant operating temp. Yes the combustion process builds a lot of heat but contact between the cylindar walls and the rings will pull heat out of the rings. How much and how quickly, I don't have those numbers nor have I done the tests.
Next it is my guess that the Engine block "grows" a certain amount as the temp increases from amibant to operating temp. Until the engine "grows" the clearance in the engine is mostly likely not the best for the long term life of the engine.
I too always think cooler is better but you also have to remember it was designed to operate at that temp. You need to fully understand what your doing to the machined parts in the engine if you change things.
Just my two cents
Next it is my guess that the Engine block "grows" a certain amount as the temp increases from amibant to operating temp. Until the engine "grows" the clearance in the engine is mostly likely not the best for the long term life of the engine.
I too always think cooler is better but you also have to remember it was designed to operate at that temp. You need to fully understand what your doing to the machined parts in the engine if you change things.
Just my two cents
Race Director
Joined: Mar 2001
Posts: 11,405
Likes: 26
From: Whippany NJ
CI 6-7-8-9 Veteran
St. Jude Donor '08-'09
NCM Sinkhole Donor
LMAO! Another thermostat thread!
160 is fine, others say its bad for the motor but they cant prove it! Having all kinds of engineering degrees and experience still does not prove that the motor will blow up. Period!
it will get you a good career though!
160 is fine, others say its bad for the motor but they cant prove it! Having all kinds of engineering degrees and experience still does not prove that the motor will blow up. Period!
it will get you a good career though!
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
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
Safety Car
Joined: May 2000
Posts: 4,820
Likes: 347
From: Albuquerque NM
Originally Posted by Evil-Twin
You obviously have no idea about an all aluminum alloy engine designed with tight tolerances that emits less emissions... the information above is correct, and if you didnt want advice and seem to know it all why the *** did you ask...????I have seen hundreds of case studies on LS/x engines, right from the test lab.... You do what you think is best.
Bill aka ET
40 years of automotive engineering
15 of them with GM and the last seven with the C5 engineering team.
retired 2001
Bill aka ET
40 years of automotive engineering
15 of them with GM and the last seven with the C5 engineering team.
retired 2001
My point remains, if frictional losses went up with slightly lower operating temps, then the dyno power would be less, not more. The motors run cooler ALLWAYS MAKE MORE POWER.
If you were to argue that an engine run cooler may WEAR more quickly, I wouldn't have the facts to disagree. I will say, that after 25,000 miles running at lower operating temps mine runs stronger than it ever has, and doesn't use more oil than it did new.
Quiksilver, AKA Wayne
BSEE, PE, MBA, and 23 years of testing engineer service for the USAF,
Race Director
Joined: Mar 2001
Posts: 11,405
Likes: 26
From: Whippany NJ
CI 6-7-8-9 Veteran
St. Jude Donor '08-'09
NCM Sinkhole Donor
Originally Posted by 6Speeder
Quiksilver, AKA Wayne
BSEE, PE, MBA, and 23 years of testing engineer service for the USAF,
BSEE, PE, MBA, and 23 years of testing engineer service for the USAF,
I like how you ended your post with the resume. Kind of like slapping someone right back in his face. 
Thread Starter
Safety Car
Joined: Jan 2006
Posts: 3,940
Likes: 42
From: shavertown Pa.
still keeping stat.
I have been keeping my engines cooler for the last 30 years, leaded, unleaded, small blocks, big blocks, daily drivers, and this car, that only sees the light of day when the garage door opens when its sunny and no chance of rain. I have never had a problem with any car that runs cooler than the BOOK says. When I stop at a traffic light and the temp. increases, it starts from 160, that gives me 30 deg. to play with until the light changes, I still say cooler is better. I also bypassed that heated TB to keep cooler air comming into the engine..
Burning Brakes
Joined: Nov 2004
Posts: 988
Likes: 4
From: Livermore CA
The worst cold temperature related condition with respect to engine wear is a cold start followed by heavy loads. The piston (aluminum) expands twice as much as the steel cylinder liners and is directly exposed to the flame front. If the block has not been given enough time to warm up a tight condition occurs due to the now big piston and small bore. With two cycle dirt bike engines a siezure can occur, in four cycle engines like the LS1/6 you would probably only cause some increased piston wear. The operation of the LS1/6 at a temperature 20 less than what GM programmed it for can only increase the specific output a little and prolong the elastomeric sealing materials. I agree that the 195 thermostat is for emission reasons. 160 or 180 will allow your engine to heat it's oil to the 200 degree level where the moisture will leave it. 160 might not quite due it in cold climates. This heating off of the water in the oil prevents the oil from becoming acidic as quickly. The fans must be reprogrammed to kick on at a lower temp and a larger capacity radiator is necessary if you really run these engines.
Le Mans Master
Joined: Feb 2006
Posts: 5,267
Likes: 40
From: Phoenix AZ
Why would you want to lower your thermostat anyhow?
IS YOUR CAR OVERHEATING ??????? Or is it just a trendy mod?
If it is overheating, and your thermostat is not faulty, then its most likely a matter of the efficiency of your radiator. If your cooling system cant handle full throttle at the racetrack without overheating, its the ability of the radiator to remove the heat that is in question, since the thermostat would be wide open when hot.
I put a 160 in my tahoe, only because I tow trailers and it helps with pre-ignition and detonation, because its too old to flash the computer with less timing or more fuel. I have found it now gets worse fuel mileage due to a colder engine requiring more fuel. But since the engine is cooler, there is less expansion of the gasses in the combustion chamber so there isnt much more power. Just less pinging under severe towing / load.
The optimum engine would have super high engine temps with ceramic pistons and liners so the cool intake air charge would expand alot more and make more power.....but due to limitations of materials and $$$, this is what we have for now.
No degree here, ASE master tech for 15 years.
IS YOUR CAR OVERHEATING ??????? Or is it just a trendy mod?
If it is overheating, and your thermostat is not faulty, then its most likely a matter of the efficiency of your radiator. If your cooling system cant handle full throttle at the racetrack without overheating, its the ability of the radiator to remove the heat that is in question, since the thermostat would be wide open when hot.
I put a 160 in my tahoe, only because I tow trailers and it helps with pre-ignition and detonation, because its too old to flash the computer with less timing or more fuel. I have found it now gets worse fuel mileage due to a colder engine requiring more fuel. But since the engine is cooler, there is less expansion of the gasses in the combustion chamber so there isnt much more power. Just less pinging under severe towing / load.
The optimum engine would have super high engine temps with ceramic pistons and liners so the cool intake air charge would expand alot more and make more power.....but due to limitations of materials and $$$, this is what we have for now.
No degree here, ASE master tech for 15 years.
Burning Brakes
Joined: Jan 2004
Posts: 1,202
Likes: 2
From: Bergen County NJ
Originally Posted by bob guzzy
HI: I have put a 160 stat in my z06. and temp is at 170 highway. 20 to 30 drop in temp,( no difference like factory stat if you just let it idle )but that drop in temp,will add a little life of your engine. also when you refill your cooling system remove the bleed pipe from the right hand side of the radiator, as your filling the air pushes out, A LITTLE COOLER IS BETTER....
Scott, C.P.A.
Pro
Joined: Mar 2002
Posts: 632
Likes: 0
From: Enterprise AL
I had to check my calendar.... and what do ya know, it's 2006 not 1960..... stock LS series aluminum engines make more power at the factory recommended temps. If you have reprogrammed the fuel and spark delivery, cooler temps may help prevent premature detonation, so the timing won't be rolled back.
Don't believe me, go to a dyno, the second pull will show an increase of 10-15 hp and TQ because the temperatures have increased closer to or actually at the designed temperatures of about 190 - 200.
If you have driven the car enough to already be at the operating tempertures, it will not increase.
Aluminum blocks and heads tranfer heat, (read lose heat), much faster than cast iron blocks and heads of old.
Don't believe me, go to a dyno, the second pull will show an increase of 10-15 hp and TQ because the temperatures have increased closer to or actually at the designed temperatures of about 190 - 200.
If you have driven the car enough to already be at the operating tempertures, it will not increase.
Aluminum blocks and heads tranfer heat, (read lose heat), much faster than cast iron blocks and heads of old.
Le Mans Master
Joined: Sep 1999
Posts: 5,464
Likes: 2
From: Private
you can tune the car more aggressively at lower temps, produce a little more power, but if you are running the car really hard and get your oil and coolant temps up high on a constant basis, this will help (aka road racing, which I do). Also, these cars are designed to run 190+, but really that is mostly for emission purposes. The higher temps burn more fuel and reduce emissions. I run a 160 with fans coming on at 190 and a Dewitt radiator oil cooler combo. My car runs about 182 water and 180 oil.
Safety Car
Joined: May 2000
Posts: 4,820
Likes: 347
From: Albuquerque NM
You know, if it were the 60's it'd be easier to say what works and what doesn't. Back then you knew what the timing was set to and what the A/F was. Now.... the PCM has multiple protection schemes built into it, which vary both as it thinks is needed. Unless you are really careful you can fool yourself into believing that running the engine hotter makes more power. When you go WOT the pcm adds fuel based on the fuel map, ignoring the O2 sensors but DOES modify the table based on LTFT's and STFT's. Unless you clear those fuel trim tables you just don't know what you'll get on the dyno. I can make the dyno read 10 or more hp higher or lower by just varying how fast I go from steady state throttle to WOT. I can also do it by varying the starting RPM of the test. Eliminating variables, so that you are only testing one change, like coolant temp, is harder than most folks imagine and you can easily get false data.
The truth is, once you get your fuel/air numbers set right, most LSX engines will give a little more HP when run a little cooler than the stock thermostat and fan settings allow. From my testing and tuning experience, this seems to be because it allows the PCM to give more agressive timing without detonation.
The truth is, once you get your fuel/air numbers set right, most LSX engines will give a little more HP when run a little cooler than the stock thermostat and fan settings allow. From my testing and tuning experience, this seems to be because it allows the PCM to give more agressive timing without detonation.