temps indeed rarely go over 30° here, celsius that is. in my experience just about any car with a functioning cooling system will do that (except my 2008 zo6 for some reason).

 

More great input. But I dont think I want my motor running at 160ish all the time as I believe it is not getting up to operating temperature. but it is good to know that there is at least one vette out there running cooler temps.
I have set up an appointment to have my fans kick on at a lower temp. I'm choosing : low speed fan = on at 205, off at 200, and high speed fan = on at 210, off at 205. After I made the appointment for the fan adjustment, the tuner called me back and suggested a 160 thermostat. As far as I know, Chevy does not make a 160, and I want to keep my car as OEM as possible, so I'm going to throw in a 180.

My thought is the 190 "starts" to open and 190 but may not get fully open until some degrees later ( 195,196,197,etc. ? ).
So maybe by installing a 180 it will get fully open a few degrees before the 190. Maybe that will make a few degrees difference.

And of course my reasoning for the fans to kick on at a lower temp is for when the car is idling at a stop for what ever reason. So if I can keep the temp in the 200-205 range at a stop, I would feel comfortable with that because when the car gets going I know the temp will drop just a bit , hopefully in the 190's like I would prefer. Then when I replace the radiator with a 3 row, I'm sure the cruising temp will be in the 190's.

While I just mentioned radiator, there are some vendors indicating that a wider 2 row is more efficient then a 3 row. Any thoughts on that?

 

Do yourself a favor and do a deep Google dive on 160 thermostat in a C5. This topic has been beaten to death for decades now. A thermostat simply allows coolant to flow at a certain temp, it has no role to play in what temp your coolant eventually reaches. Opening it at 160 vs ~190 during normal/daily driving will have one result: your motor will just take slightly longer to reach operating temperature. Summer, no problem. Winter, it's a pain in the butt waiting longer to be able to drive spiritedly. I ran one myself for a year or two and was very happy to swap it out with a stock tstat as soon as I had a chance. If you really want to swap to a 180, it's not a huge deal and won't hurt, it just won't accomplish your end goal without being coupled with a more efficient radiator/fan setup.

You can also set your fans for whatever you want, but ~200 for low is a common starting point.

A thicker radiator will be more restrictive than a thinner one. You want the most airflow you can get through your radiator. The stock shrouding is already pretty efficient in forcing air to the radiator, but if you want to see an appreciable benefit with a thicker radiator while the fans are spinning, you'll probably want upgraded fans that pull more air. As you can see, you can easily go down a rabbit hole and spend $1,000+ on an upgraded cooling system by the time you're done. Cheapest and easiest solution is to just make sure your stock cooling system is in good health and your motor will be perfectly happy for a long time.

 

You have a very unique cooling system, kudos to you sir

 

So heggsc5, Yes I do know that with a lower temp tstat, it will only open up the cooling process a bit sooner, but not lower it.

So just about 15 minutes ago, I ordered a Dewitts 3 row for an Auto. In addition I also ordered their fan system as it spins about twice as fast as the OE fans. They currently have a sale going on now of 10% off and free shipping. With the sale I had to take advantage of it. I do have an appointment set for Wednesday, May 1st with a tuner to reset the temps my fans come on. But earlier today I ordered the HP Tuner set up so I can do it myself, so I will be canceling the appointment. I know will have at my control the ability to reset my fans kick in temp, and thanks for the 200 degree heads up, I think I will start with that.

 

Good move grabbing HP Tuners so you can do it yourself. Now you'll be able to adjust other useful stuff as well and can also do remote tuning with great tuners nationwide vs just being stuck with whoever is local to you 👍👍

 

I can only relay my experiences. I have a 160° T-stat. Have had it and a DeWitts for 18 years, still running stock fans. I have never seen coolant temps under 169°F, ever, and the 169° happened in 35° ambient, coasting for 4 or 5 miles down the Great Smoky mountain National Parkway, from Newfound Gap to Cherokee, N.C.. A 160° stat STARTS opening at 160°. Any stat's rated temp is where the stat STARTS opening, NOT the temp it's FULLY open. My engine would never run at 160°. I had metallurgy classes that were many years ago, so I may not be totally accurate here, but here goes: The hotter a metal gets, within reason, not to the melting point, of course, but the hotter it gets, the coefficient of friction is reduced. In other words, a hotter engines rings have less friction at 220° than they do at 175°. I was into engines even back then, and do remember asking the instructor about it, after mentioning we hot rodders like cooler running engines. He answered that is because the air is being heated thru hot intake manifolds, which was the case back then. Of course, our LS engines have no hot coolant running thru them. He told me the ideal situation would be having an engines coolant at 200°+, and the intake air temps at 0°F!! A perfect world, in other words. Personally, I like my coolant around 190°-195°, which helps keep the computer from pulling timing. I can almost guarantee some sort of spark knock if your coolant is at 235°. That's way too hot, and to avoid spark knock, the computer is going to pull timing if your motor is that hot. My worthless .02.....

 

hggss5, I still have much to learn about the tuning, but I thought I would start with things like the fan kick on temp . I will be watching may videos about tuning before I even think about entering into the territory
of changing timing or air/fuel mixture. And the remote tuning stuff is still another language to me. But if I can tap into the knowledge base of other experienced tuners, that would be great.

And grinder11, the whole reason I started on this quest was to get my motor to run in the 190's. I guess I will accept that the temp will rise a bit when stationary, but only to a point, hence resetting when my fans will kick on.

When I get the HP Tuner and reset the fans and install the DeWitts equipment, I will let everyone know the results, not just in operating temps but IF I can feel a difference in functionality.

When I purchased my car it was for low $, and I expected and wanted things I could fiddle with and fix. And I got just what I wanted.

 

One point I want to emphasize is you do not need aftermarket fans! I cooled a 427 in 110° heat with OEM fans. If you're racing, then this info may not apply. When I took my car in to have a tune done, the guy asked me straight off 'What fans are you running?' When I said stock C5s, he said 'Good, theyre as good as any for normal street/strip use.' When a 20 year pro tells me that, and combined with my own 20 years of C5 experiences, I believed him. YMMV, and this isnt a knock on aftermarket fans....

 

I get it Grinder, but I have already ordered the DeWitt fans and I want to give the cooling every opportunity to do it's job. The OEM fans have worked for 72,000 miles, and With all the good things I have heard about DeWitt, I am anticipating their fans will perform as well as the OEM fans and hopefully better.

 

a few facts (imho) about cooling systems:

1. "evidence of a very small coolant leak at the lower right corner": iv had such a leak for many years now, without any consequences

2. about 2/3 of the rad area is solid metal (just saying, if you make airflow calculations)

3. the fans turn off at 35 mph (out of memory), so during normal* use they have no effect

4. a thermostat will indeed keep the coolant at the temp its rated for (+/- 1°c). and yes, it opens slowly, thats how a regulated system works. i had 70°/80°c stats on many cars and on all of them temps were stable on the street. racing is different of course, especially if power levels are higher.

5. i have often used a manual fan switch and it worked well. here is a little trick: in the case of double fans wire them so you can switch between series and parallel. this gives a nice level of controll and no problems with relays or connectors overheating.

* if you really use a c5 for commuting in 3-lane traffic in 40°c heat its a different story

 

Thanks for the input Romandian,

1. I could see the leak maybe never leaking again, I just don't want to take that chance. Plus replacing it plays nicely into my hands of wanting the coolant temp to run in the 190's.

2. And so do you think the 3 row dewitts will be more metal?

3. I know they shut off at 35MPH but I'm more concerened about what the temp will climb to when stationary. The is a you tube video from a guy calling it: My Corvette Life, 1998 vette in with power adders and he lives in Phoenix. He installed the exact same radiator/fan set up from DeWitts as I will be installing. He video reported during a 106 degree day in Phoenix his cruising temps were at 190. He then did some speed runs to get the temp up and it climbed to , as I remember, 198. Then as went back to cruising speed and the temp dropped back down to 190. When he was driving home in his neighborhood, and parked the car the temp was at 189. I believe if he can do that at 106 in Phoenix with a 190 tstat, I can do that here in the Chicago area.

4. I will not be tracking the car and so it will only be street driven, my daily, except if it snows. If I need to I will install a 180, hoping by the time it is fully open, I will still be running in the 190's.

5. I have these fan kits on you tube so you can with a remote turn on the fans, but I didn't want to have to do that so that played a bunch into my reasoning to go with a better radiator.
However, I did think about wiring the fans so they would both turn on at the same time, at the lower degree setting.

 

Let’s keep this simple, because it is. Once you get the DeWitts installed you won’t need to worry about the fans. It will run cooler simply because of the greater efficiency and capacity. Changing the fan limits is just a bandaid for a bare minimum radiator GM gave us. Running 220° is crazy.

No need to over think this.

 

They do already, stock wiring runs both fans either in series at 1/2 voltage for each or with each at full voltage.

 

I would surmise to say that the reliability of the Chevy Small Block V8 continued well past the emissions age.

 

Is the 3 row a new offering from DeWitts? I thought all they had was a 2 row? This should be as good as it gets for a testimonial, because since I installed my DeWitts around 17-18 years ago, I don't give cooling a second thought. Even with an ASP 25% underdrive balancer, My coolant only exceeds 200° on a 90°+ day, and then only when idling 3-4 minutes at a long Florida red light. You can't go wrong with DeWitts......

 

No doubt about it, I have been accused many times of over thinking issues I am working on. I think it will get simpler when I have the issue solved.

I did not realize the fans could run together.

yes, thank God the small and Big blocks are still running strong.

And I was pretty sure what I ordered was a 3 row. it is twice as thick as the factory radiator.

Hopefully I will be getting my DeWitt's products in a few days, then I will install it along with new radiator hoses, and I will report to everyone what the results are.

 

OK Guys, now I'm disappointed. Let me start with a story on a you tube video I saw.

The video is " My Corvette Life", I believe the name of the host is Chris. He has the identical car I do, 1998 Base C5 . He purchased it with 120,000. He has done some modification to it like exhaust, intake, cold air intake, etc. so he generates a bit more heat I would think then my stock eng., the only thing I have is a cat back Borla exhaust. Nothing else.
Well Chris replaced his radiator with the exact same one I did. A DeWitt with the two fan accessory.
That is what I have replaced on my 1998 Base Convertible with 72,000 miles.

Now after Chris replaced his radiator and fan system, he did a video of himself driving around town and videoed the eng temp as he was driving. And he described how he was driving during the video. So this is what he did.
Chris lives in Phoenix. The day he did the video the outside temp was 106 degrees. What a great temp for a test. As he was driving to the expressway, he reached temps of 190. He then got on the expressway and cruised I believe at 75-80 mph. And during that time he maintained the temp of 190. He then slowed down and did 3 hard throttle pulls, rowing through the gears in a attempt to build heat in the engine which he did, he ended up at the highest temp of 198. He then exited the expressway and drove through the streets of Phoenix to go home, and as he did so the temp gradually receded, and by the time he pulled into his driveway, he was at 189. Now keep in mind the outside temp was 106 and this is all on video.

Now I am in the Chicago area. Yesterday, my son and I replaced my radiator and fan system with the exact same DeWitt system that Chris did from My Corvette Life.
This morning I drove to work , a relatively short drive of 6-7 miles, and the outside temp was 42. But the time I reached work, my eng temp was 203, in 42 degree weather.

So can someone explain to me , why my car, with zero engine modifications, with the exact same car as Chris, is running higher engine temperatures in a climate that is 62 degrees colder? I've only had possession of the car for 3 months, but I believe the thermostat is still 190.

I am so frustrated now as I want my engine to run in the 190's which in I believe is not too much to ask for in the Chicago area.

 

Maybe his AC condenser is clean and yours isn't? Not sure if you showed that or not.

 

So you're saying in both scenarios, both cars had stock thermostats? Sounds accurate to me, what's the issue? You're not going to run cooler than ~190 because the thermostat isn't even letting any coolant flow yet. You're talking a few degrees difference on an "analog" pressure based device...

Seriously nothing to worry about, don't let it drive you mad for no reason. But as supercharged111 mentioned, clean out your condenser if you never have and you'll probably drop a few degrees there. And of course make sure your system is fully burped.

With the larger radiator installed, you "should* see a difference with a slightly lower tstat now as well.