here we go again

 

Doc will take good care of you.

 

Never could understand all the concern over normal operating temps

 

Yup I just did not know about the vette. Only owned 2 GM products in my life. I am old school drag racer and know temps can do some bad things. It was fine going down highway just let it set in slow traffic it would heat up.

Just wanted to ask about it and looks like I open a can of worms. lol

 

That's why I recommended doing a search on "Sweet Spot". The person who wrote the posts is a retired GM engineer who worked on development and provided a lot of good technical information on engine temperatures as related to oil and engine longevity. He goes by Evil-Twin.

 

There are many reasons to lower the operating temperature and as long as you understand that there are trade off's and know why you are doing it you will be fine. I run a 160 t-stat in the summer and a 180 in the winter. Talk to a professional tuner.

If you ask E.T. or read everything he has ever posted on the subject, you will learn that he runs a lower temp t-stat in the summer and changes to a higher temp for the winter.

 

I use a 180* year round and my temps run the same year round at 192*

 

The C5 cooling system is designed to fluctuate up to 40 degrees F. Its designed in . Its impossible and a big stretch of the truth to say any stat at any designed temp ( e.g. 180F )will maintain a constant temp without fluctuation in a bottom feeding C5
AS far as someone who wasted their money buying a 180 stat and it never gets below 192...they just bought another factory stat that was re-boxed. I bought three different 160 Stats and tested each one, only to find that they were all re packaged factory stats. Only the Halltech Stats was a true 160 stat. Termostats are designed to control how cold the engine will get at operating temps, not how hot they get. A 180 F stat will control the engine temp down to 180F on a cold January morning where the ambient temp in Tenn can get down to 19F, like it did this morning, and should get the coolant down to 180F which would be a long term kiss of death for engine life. With proper heat exchange the stat will fluctuate open and closed to maintain the engine coolant wont get colder than 180 F. Coolant temps have a direct relationship to oil temps and the ability to properly lubricate the engine, specifically the top end. With coolant @ 180f, it will take a toll on the additive package in the oil and break it down due to shear. Engine oil and coolant should be warmer than those with 1960's automotive mentality might think. Hot is much better than cold when it comes to engine life.. This is a paradigm change brought on by Dave Hill's direction to design a 200,000 mile benchmarked engine. Tuners will tell you to run your engine cold so they can get more horse power out of it with some timing advance.. Tuners never tell you what running a cold engine does for your engine's life. This is not a 1960's cast iron block with a designed engine life span of 100,000 miles. Its their job to get you more HP. that's what you pay them for. A cold engine makes their life so much easier, but at your expense. MY 160 stat will get my coolant temp down to 160 f and my oil will never get above 200F, if I'm on a highway doing 70 and its 20 degrees outside. That's why is not in there Nov, Dec , Jan, Feb., or March. the 160 helps me maintain a sweet spot when its 90F + in the summer, here in the North East. it allows me to lower them fan set points. You never want to have the fans run all the time, they are not mechanical but electrical and are designed to cycle on and off. Or you can replace them every five or six years.
More of the same form me
Bill aka ET

 

Two years ago I spent several hours reading E.T.'s posts on t-stats and oil temperature and decided to go ahead with the lower t-stat knowing that there will be more wear. That's the trade off. I can only get 91 octane gas in my area and my car pings even on the coolest days with the stock t-stat and factory tune. It is terrible in the summer and it takes all of the fun out of driving my car. I took my car to a good tuner and he tried to make it better with the stock t-stat but my car was still lifeless. We changed to the 160 t-stat and made adjustments to the tune and that brought it back to life. It doesn't get very cold here so this year I decided not to change to a higher temperature t-stat for winter again knowing that it will not keep the oil temp as high as I would want. I will live with what ever happens knowing, thanks to E.T. if something fails prematurely it was likely due to lower oil temperature.

If anyone is wondering I have a 2004 cpe. with an automatic and the 3:15 axle ratio. Other than the Z06 muffler and a Vararam intake it is stock with 90k miles on it. I don't take my car to the track unless I have changed something. My best time completely stock was 13:18@ 107.22. After the t-stat, muffler and tuning, 12:87@ 111.75. I think the tune made the biggest difference and the improvement is worth the risk in my case.

 

IPS Motorsports recommended a 160 thermostat when they installed my A&A Supercharger.
I had bought one before the install and had them put it in.
Ran a 160 in my 6 psi LT1 Camaro for 10 years with no problems before moving up and getting my M6 Vert this past summer.

I prefer keeping my coolant temperature at 200 degrees or less to leave more room in case my foot gets extra heavy especially when running the AC with the top up at the peak of summer which is about 90-95 degrees around here.

 

The idea to personally tweak your individual C5 for your own personal driving conditions is something that I've always advocated here over the last 13 years. Whether its tire tuning for greater fuel economy, or for tire longevity, finding the sweet spot for your engine's coolant and oil , makes the C5 platform a perfect example of having a car that is adjustable enough to perform for your personal driving style. Some people feel the need to squeeze every ounce of horse power out of the car to gain that extra 1/10th. sec. While others will do the same thing and never see a track event. Some will take the design q's from GM and run with them. Some of our members who have done this have seen 400,000 plus miles from an engine that was designed with longevity in mind. While most cars are one size fits all from the cookie cutter, a C5 is flexible enough for you to make it different from your neighbor's C5.

 

FWIW, I put a 180* t'stat in my car this past summer, while I had it apart to install an ATI harmonic damper. I got the t'stat from PRW (professional racers warehouse). My car, in normal summer driving, runs consistently at 183-185*.

 

Every T-stat is not created equal. Just because one is rated at 160* or 180* or 195* doesn't mean it will open at that temperature, I've seen some t-stats as much as 5 degrees off. Like ET was saying, t-stats do not control how hot the coolant gets, it regulates coolant flow. Air flow and radiator size play an important role in coolant temp.

 

You can easily tweak the LS1 thermostat as well so that it will open at a lower temperature. I run two and have been playing with the summer thermostat open temperature for a few years to get it right where I want it.

 

When I put in an iron block engine and turbo set-up I switched to a 160° Tstat.

When I've been driving in the Texas "cold" lately (~40° ambient temperature) I've noticed that my coolant temps never go above 180°, and the highest I've seen my oil temp is 193° after ~30 minutes of driving, it usually is in the 170-180 range after a normal drive.

The real answer is I shouldn't drive so much in the cold, but my other car is down for a bit. But I'm a little leary with my oil temperatures so low.

Maybe if I'm doing some "spirited" driving when its 110° outside with the A/C on, perhaps a 160° Tstat would be a good idea, but I'm probably going to switch back to a stock Tstat and see what my temps are, before going back to a 160°. I'm not really convinced that its necessary. Just makes it take longer for the oil to heat up to a good operating temperature IMO.

 

You can also drill a 1/8"-1/4" hole into the flap of the thermostat to lower the temperature.

 

nothing wrong with those temps.. 180+ oil temps is plenty hot enough to evaporate any crankcase moisture in a hurry

 

it's a known fact LS engines make the most HP with engine temps 195-205. why would you want to run your engine any cooler?

 

where did you find this fact?? heat soak will not make more HP. at 170-180 where a 160 t-stat will put you, I know from experience on multiple vehicles, Fbodies, Ybodies, Bbodys, and Gbodys. that 160 t-stats are perfect for added throttle response and HP especially with a tune because tuners can add a lot more timing without detonation for even MORE power. I've been running a 160 on my 03 Z for 2 years and over 10 years with my fbody with not one single issue. I run 11.88 @ 117 with just intake and exhaust - stock tune in the Z.

with that said, 160 is about the lowest I'd go. 140-150 tstats might have some issues with water evaporation.

 

with 4 test mule engines and 200,000 test miles each in a test frame. We at GM know that oil temps under 200F is the kiss of death for this engine's life. Dave Hill wanted a 200,000 K bench marked engine and this is one of the ways we got it there in combination with the OLM, oil spec specific to the C5 LS1,( Not the F body application ) and maintenance schedule. LS1 engine is the first engine developed in the world for a production based automotive engine " Ever " to achieve 200,000 miles" as its production bench mark.

So many people on this forum live in the past as if this engine came from some past design. its just another case of the blind leading the blind. BTW for the clueless out there, water evaporation has nothing what so ever to do with thermal shear, which is what occurs with cold engine oil. Thermal shear is the breakdown of the oil and additive properties due to excessive thermal breakdown under extreme pressure forcing cold oil into tight places over time.
Bill aka ET