What's the normal engine temp of a basically stock C5? I have installed a vented hood and in cooler weather the temp stays about 150 to 160 around town and on cold days will drop back to 145 on the open road with all that cold air blowing in under the hood. Let it sit for a few minutes running and it will go up to about 200. Is 200-220 about normal?

 

Sounds normal to me. These things were designed to run in those temperatures. A lot of people freak when they hit 220 and go out of their way to get the temp down. I personally don't worry about it. I consider that a WAD condition (Working As Designed) and if the design engineers weren't concerned about it then neither am I.

The high speed fan should kick on at 220, if that's not happening then that's cause for concern.

220dF is not approaching the boiling point of water under pressure. I believe the boiling point of water is increased by 3dF per pound of pressure, so at 16 PSI you're well over the 212dF boiling point of pure H2O. Now, add a solution of water that's diluted by about 50-65% antifreeze and you have a solution with a boiling point which is MUCH higher than your car should ever reach.

I'm sure others will point out the error of my ways...

Again, I think people worry about it needlessly. Keep the shroud clean of crap, radiator at the proper fluid levels and drive the sob.

 

My none vented system runs in the high 190s.
rr

 

amen

 

In my opinion if you are running 145 on the open road that is too cool, You should be running around 180-190 on the highway, In town on a hot day you will see 200-220.

 

actually Bill, I'd have to agree about the low temps. Was early and the coffee hadn't kicked in yet before and I focused on the high end.

 

145* on a car that is at full operating temp is way too cool. My stock car with a stock hood runs around 192-195* when at operating temp and will hit up to 220-225* or so on really hot days in stop and go traffic.

 

So you do have a big problem, looks like you removed your thermostat completely. They don't make a 145 thermostat for a C5..... the reason they don't is because running at 145 will absolutely destroy this engine and take 50 % of its life away. the oil temp should never drop below 190F. You obviously have no clue about modern automotive technology. Cold engine temps are your enemy . it's much better to run a little hotter than it is to run a lot colder.
You've got to get your head out of the 1960's mentality. The LSX engine has a sweet spot 190/200F coolant and 200/220F oil. running anything lower than that after warm up is very very bad, considering this engine can easily do 300,000 miles, I have members Private message me about how great their car is even with 400+K on their engine
A thermostat is designed to control how cold the coolant gets not how high it gets. Once open a 190 stat can easily see 220/230F/
once a stat see temps going below the designed temp is closes to keep the temp higher.. if you car is seeing 145, your nose is growing or you have no idea what you are doing .
Cold oil with starve off the top end lubricity and will do something most people don't even know about, and that is called shear. which will break down the oil and destroy the additive package leaving the oil empty of valuable components of the oil. What happens is you destroy the very special additive package design for this car and the spec GM has demanded for this engine design. GM 4718M specification

 

Another great thread for a newbe! Got caught in some mostly stop traffic because of a wreck on the freeway the other day and saw the coolant temp pop over 200 and panicked.

Thanks

 

ET, I have a question about running with cold oil. Obviously, it takes some time for the oil to come up to operating temperature. And even on hot Texas summer days that can take longer that a trip to and from our local grocery store. How important is it, or how often is it necessary, to get the oil to 200+ degrees? My wife drives a C6 (LS3) and I have told her to take it for a long enough drive (really had to twist her arm...) to get the oil to ~200 even if she only needs to take a short trip to the grocery store. I'm sure that the OLM algorithm has taken all of this into account, and we will change the oil more often with many "short" trips. So am I making her waste gas, or is it important to make the oil reach the operating temperature every time, or every "x" times, the car is driven.

Thanks,
George

 

Mr. Bill is right on again.

 

The OLM takes short trips into account and decreases the oil life accordingly, there is a big difference in driving in closed loop and open loop. running at cold oil temps at start up is only natural and designed into the OLM. Running at cold temps all day , on the highway is not normal driving. you do not have to heat the oil up if you are driving short trips in closed loop. The oil life will be dramatically decreased. We seen many cases where this type of driving will require an oil change in 2000 miles. I know this is all confusing because everyone gets their knowledge from friends and family.. many people overthink maintenance too. This car is well designed, able to reach mileages of 400K + and all it takes is follow the guide lines, use the right oil, follow the maintenance schedule and follow the OLM and enjoy the car.

 

Thank You Bill. Although, I doubt she will significantly reduce the additional "drive time" to heat up the oil, since she loves driving it so much, I will let her know that she doesn't need to!

 

I would like to know how I could get my stock 02 to run 180-190 on the highway. Since the day I got it, it runs 198-205 at highway speeds regardless of the out side temp. Winter or summer. What gives? I have cleaned the radiator and AC condenser several times. I know these aren't high temps, but I always see guys claiming 180-190 temps.

Thanks

 

Well in my case I installed a lower temp thermostat and had the fans reprogrammed, 198-205 I wouldn't worry about that, That is fine.

 

Thanks!

 

reprogrammed fans here. They come on sooner so the temp doesn't get as hot before they kick on. 180-190 on the highway, 200ish stuck in traffic.

 

My car, I hated the stock t stat. Over 210 and I could smell the oil cooking, oil was black, hated it.

Did a PCM reprogram with some bolt on mods, included lower fan setting and installed a 160 t stat that runs the oil temp not at 160 but around 180. I am much more comfortable with this and it took 2 oil changes to get my oil clean again. Also added a catch can with a new manifold and I am no longer re-ingesting oil and making a mess in there. Car runs so much better now. Perfect.

The 'design' is not that we are re-engineering. They are not designed to be the best motor they can be. The engineers are forced to balance power/performance and emissions. We can change that some with good very results, unleash some torque held in reserve and still pass our annual emissions inspections. It is not a big deal to increase performance, we are not second guessing the engineers.

Being trapped in the 60's mentality of trying to make a good product even better, absolutely not trying to second guess engineers with 40 years experience and 12 years experience specific to the development of the LS1 with their decision to cook oil black to the point of being able to smell it while driving, stuff a sensitive oil pressure sender unit directly on the block behind the intake manifold destined to fail in short order and very difficult to replace (revenue for repairs), "invent" chronic squeaky pully syndrome (revenue in repairs), place a lead acid battery directly above a pcm (revenue in replacement) and create a means for a motor to ingest and regurgitate on its own oil through the pcv system instead of adding a $49 dollar catch can (revenue in trade in towards a new car), among other things. With all due respect...........genius.