I live in Atlanta and sitting in heavy traffic is a way of life .....

Recently we have had more than our share of 98 degree days and I noticed that my car seems to be running hot ( or I never noticed that it was always running hot ...)

Friday, I was sitting in rush hour traffic with the air on and when I got into heavy stop and go, the temp would climb up from around 200 to about 215 , it got to 220 - 225 a few times . As soon as I started to move it would drop back down slowly to 205.

Once I got on the highway it would run around 196 to 198 but if we slowed down it would go up to 205 - 208

Thinking I had sucked up dirt and stuff today I took my shroud off and cleaned the front of my air conditioner condenser, coolant radiator and checked the fan connection ( it looked fine ) .

There was dirt in the front of the air-conditioning condenser and some on the radiator but not enough to cause overheating

The fan is coming on and I can hear it kick to high when turn on the air conditioning

I know I can put a 180 thermostat in ( I don't want a 160 ) and kick my fans up in the tune but are these normal running temps for a stock LS3 with headers and a tune ? am I worrying for nothing ?

Dave

 

Mine runs hotter than yours under the same ambient temperatures and has done for the last 10 years and 133K miles. I changed the waterpump + T-stat once, just while I was in there, and replaced the leaking OEM radiator with a DeWitts. No difference. Fan runs fine.

Many users have the same experience as me, while some others claim that their cars seldom crack 200 degrees. Go figure.

 

Wow this makes me feel better , thanks guys !!

Dave

 

that is normal. Some folks complain that after adding superchargers, the intercooler blocks the air to the radiator and their cars run warmer, sometimes even shutting the ac off. I have found that running a 75-25 mix of water to coolant keeps engine temps down.

 

Normal

 

We were out today and approx. 98-100', Dave, as we were cruising slowly looking at the River rats in the Park Moabi Channel, I got to 208, usually does but then as soon as we start moving it was back to 195-196 as normal. I have seen it get to 217 if we sit for too long but not worried, no headers as you know Seems that the LS3 runs like that
NSF

 

I guess it has been doing this all along ....... I feel better hearing that others are running the same Temps

Dave

 

I run as high as 210* but average 199/200*.

To put it in perspective since we're only comparing Corvettes to Corvettes, I was doing some datalogging on my Wife's Jaguar XJR, this is a supercharged engine; just normal speeds. no WOT or stop/go. It ran consistently at 215* and the cooling system is in good/normal condition.

Something to keep in mind about tstats, and you see the postings every once in a while - someone wants to put in a 160* to lower temps, and even claim it did lower temps. Whether it is a 180 or 160, doesn't matter. If you're running consistently higher temps above the tstat rating, it is wide open all the time. So a 160 will not do anything over a 180 if you're seeing temps in the 200s. Theoretically, if that were the case, then why not remove the tstat and not run one at all and really lower temps.

Also agree with above statement, modern cars, by design, run hotter than they used to for better emissions.

 

Well my bad, I deleted my post.

I was referring to the oil temp when saying I saw 235 temps. I see the OP is speaking of coolant temp.

Coolant wise I will see high 208* at the most.

Usually runs 192-196* with the 180* stat.

Now I have the 4:10's so my rpm is higher and this will run the water pump faster to cool.

The 208* was in Vegas in traffic on a 110* day.

Around the SF Bay Area I might see 203-205* if real hot and in stopped traffic.

And my A/C is always on unless really cold out.

I run a couple bottles of Water Wetter too with the Dex A Cool 50/50.

 

When I hear drivers talk of running temps I always think engine oil.

 

That is because the specific heat (heat transport capacity) of 75/25% water to EG is higher than 50/50. Car makers design and use 50/50 so that vehicles are 50 state ready for all seasons. Straight water is 1.0 btu/lb-degF while straight EG is only ~0.6.

 

use Water-wetter" and 60-75% water to AF and see your running temps drop dramatically

 

Is it possible for a thermostat to fail half open or stick and not open fully ??

I always heard that when they fail they in the open position

The reason why I ask is there is no rhyme or reason to when it runs really hot. Sometimes in traffic it sits at 210-215 and as soon as I move it comes down . Other times it will jump up to 220 and take quite a while to come down

As I got on the highway it was really hot, drove more than a few miles before it dropped down to 200 . Other times in the same traffic as soon as I get up to highway speeds it will drop down fast . Yesterday driving around it never got above 196

This was the reason for me thinking that I had dirt and debris up in the radiator

Do you guys think replacing the thermostat worth the effort ?

Dave

 

I might take your advise since it never really gets cold here and it is in a garage when I am not driving it

Dave

 

Dcasole: My 08 with a small cam,Headers and tuned on Dyno. The shop only use 180 stats and the tuner has my fan to come on at 30% at 195 and 70% at 203 and this set up has worked great. In this hot Texas heat at a stop light it will go to 203 at times and once moving it will drop to the mid 190s.If I'm using the paddles, that keeps the rpms up and it will settle around 190 or 192 at 45 mph.Cruzing in drive at 45 mph it settles at 199.....Good Luck

 

Will it cause corrosion or cause and other problem if I run less coolant??..There are a few rad additives that I see on the tube that will lower your temp.Which one works with Dexcool?..Thanks

 

Don't know about that over the long term but the anti-freeze provides the corrosion protection additives and water pump lubricants. Less than 50% concentration would likely require more frequent monitoring and fluid changes due depletion of the additives.

 

Yep, I found this post concerning this very subject Steve, for your consideration
NSF
THERMOSTAT: Probably the most misunderstood component in the cooling system, the thermostat has absolutely nothing to do with controlling maximum engine operating temperature. Period. What does it do? At cold start, it blocks the flow of coolant out of the engine until the trapped coolant reaches the thermostat’s rated temperature, at which point it opens and permits coolant to begin circulating. This aids rapid warm up, which reduces cylinder bore and piston-ring wear by bringing the engine up to operating temperature relatively quickly. Once it’s open, it modulates the flow of coolant through its calibrated restriction so coolant temperature never drops below its rated opening point, assuming the cooling system is efficient enough to cool the engine down to that level. In most cars, it’s essentially wide open all the time, and only the heat transfer efficiency of the radiator and the airflow through the radiator determine the engine’s maximum operating temperature.

If you have a 180º thermostat and your engine operates at 220º, changing to a 160º thermostat won’t change your operating temperature one bit – you need more radiator, more airflow, or both, to reduce operating temperature.

If you have an extremely efficient cooling system with more heat-rejection capability than your engine needs (runs at 180º with a 180º thermostat), changing to a 160º thermostat may result in reducing your operating temperature to 160º, but this is rare except in cold weather. Furthermore, 160º is too cold; OEM testing has proven that the rate of cylinder bore and piston-ring wear at 160º is double the wear rate at 180º, and a coolant temperature of 160º won’t let the oil in the pan get hot enough to boil off condensed moisture and blow-by contaminants, which then remain in suspension and accelerate the formation of acidic sludge. 160º thermostats were specified in the 1930s for the old alcohol-based antifreezes, which would boil off and evaporate at 185º; there’s no other reason for them.

“Balanced-Flow” thermostats like Robertshaw makes (also sold by Mr.Gasket with their name on them) are calibrated much more accurately than conventional parts-store thermostats, and if they fail, they do so in the open position. Conventional thermostats fail closed, which can cause a lot of engine damage in a big hurry if you don’t spot the sudden temperature rise.
http://www.dewitts.com/download/cooling.pdf

Given the information above, why do so many people buy and install 160* thermostats for otherwise stock Corvettes?

Totally get it if substantial mods like S/C and/or H/C packages are being done along with other upgrades to the cooling system for the track.

I'm talking doing this for a Corvette that will NEVER see the track nor ever be modded other than maybe a tune

 

Good Q Bobby. So many people buy 160* thermostats for the same reasons they buy Regal Pink oil from Hawaiian boutique Oil company (made up name, no reference intended to any real boutique oil co) in place of the specced oil for their trans, diffs, engines and PS units. It's because someone is selling these items and they're good at selling. What makes the oils work is the chemistry is such a big mystery that people do it as a complete leap of faith. "Racer Tommy uses Regal Pink in all of his race cars so it's good enough for me" Racer Tommy is sponsored by Hawaiian Oil Co. But...hush hush on that.

The tstat should be a no brainer BC it's just simple science. How can a controller rated at 160* control temps when the op temps are considerably higher 200*+++? The funniest to me is reading a post that says - "I was running 220* 230* and I switched to a 160* tstat and I now never go above 190*"...WAIT....WHAT???...But, that's good salesmanship! So convincing that the buyer is in denial.

And, as stated, although not much an argument for you and me, I DON'T want a 160* tstat if I drive the car in Anchorage in December.

 

back in the old days, I could spot the t-stat going bad in my 72 L48 350 vette. Starting cold, I could see the engine warm up normally to 180 F but then see the gauge temp climb to 210F before the thermostat would unstick and then open to drop temp back to 180F. That was not normal behavior for the car and was an earlier indicator that the t-stat was starting to go bad. I had this car for 145k miles so I knew it well!!