I see my temp going down to the 161-163 degree change over for the tach redline. Why wouldn't this be the temp sensor and not the thermostat?
I'm looking at fixing this too.

 

You always seem to have a negative comment. I don't know what crap you had to deal with in the past that has jaded you (please share if you'd like), but I think there are more positive things to think about. You do you, but maybe no one has ever told you that.

You're right about what engineers might have been told to do. The thing is that YOU don't know if they were or weren't. It's possible they weren't told anything about normal operating temperature. We don't know. So, with the lack of information, I'm better off going with what they did instead of inventing reasons they might have done different. If you have reason to believe that the ideal operating temp has been fudged for EPA reasons, please share. I would really like to know what you know and make my own decision. I'm open to learning. But I will not fall into assuming everything was done against us. Feel free to assume they are trying to screw us. I'm very aware of the nasty people in this world (I've been dealing with a person for the last five years who has tried to destroy my family just because he's an a$$hole).

And yes, the AFM system is trash and they were clearly told to do that for EPA reasons. I appreciate bluntness, but when it comes across as negative in almost every comment I've ever read of yours, you might stop and think

 

 

I installed a Motorad 207 degree today. Ordered from O’Reilly in a Murray box, try and figure that out!
A fresh coolant flush with an oil change and all is well!

 

Past? Do I have to look at the past to see a trend? I only have to look at the present.

I am NOT saying that it was done against us. I am saying that the engineers were given a criteria to design the car. Something I read about them raising the normal operating temp for emissions reasons. Daihatsu just got slapped for 30 years of fudging. Sorry but in my book, trustworthy people are a rarity not the norm.

Do you really believe AFM was EPA only? I think it was cheapened down to the point it did become a problem. Had it been designed more robustly, it might actually work. Kinda like lead paint on Chinese toys. You tell the Chinese factory to get the price to $2 and don't care how they do it and your kid eats lead paint. I don't blame the Chinese factory for cutting corners. I blame the QC of the US company for allowing it.

 

I believe the main reason for AFM was to meet CAFE standards. Playing with MPGs across their fleet is like a football team trying to meet their money cap. Fudge this, change that....add AFM even though it should never be on a vette. At least they left in a bypass like keeping it in manual mode (for autos), etc. They could have made it more difficult to bypass, so maybe someone at GM thought about our interests a little. Just maybe

 

My 2018 Z06 left the showroom floor running about 165-degree water temperature. Often, the tachometer would indicate I needed to keep rpm low due to the cold engine.
I took my car to the dealer and was told my car was designed for the low temperature, which I didn't believe because of the low RPM tach indication, and because other 2018 cars Corvettes (at the time) were running 190 degrees.

I bought a new, GM (OEM) thermostat (made in Mexico) and it performed in exactly the same way (165 degrees).

I bought a third thermostat from Rock Auto, non-OEM. Looked like a quality build and it performs exactly as it should and keeps my engine at about 190 degrees.

I doubt my two failures of GM thermostats are statistically significant, but I do read a lot about others who've had similar problems.

 

Still wondering....

 

AFM was a miserable failure in the 80's , and again when GM tried it in the 90's and here we are today trying it again .... it has nothing to do with cheap,designed not robust or QC ...it has everything to do with how complex it is to implement becaue there are many points of failure with the technology........

Dave

 

Why would you think its the sensor , My first guess ... you have a stuck open thermostat or a lower than stock temp thermostat ....

Want to verify .... shoot your radiator with a non contact infrared thermometer

 

Can you tell the temp by looking at the other temp readings. If it's a bad sensor all the rest of the temps would be normal.

 

Stay away from mishimoto..
Had multiple bad experiences.

 

Anything wrong with the ones on ebay. They run $25-$45. $30 for a GM made in Mexico in the box with the hologram sticker on it.
https://www.ebay.com/itm/23511336934...ke%3AChevrolet

 

This would work but replacing the thermostat itself only requires removing one hose. Here you would need to remove and replace all three. Nothing wrong with that but just replacing the thermostat cartridge if the housing is in good condition is acceptable and a smidge easier.

 

As long as we’re on this topic I have a question for everyone. Not trying to highjack this thread I hope but along the same topic?
I bought a 2016 Z51 just before Xmas flew up to Chicago area and drove it home to Tennessee
It was in the 30’s most is the trip and a little warmer closer to home. I noticed on the interstate my water temps averaged in the lower 160 range and oil temps maybe 10 degrees hotter. I always heard these engines were made to run hotter
I started to question if the thermostat was stuck open? My second day traveling I got into stop and go traffic after driving 70+ mph and when that happened saw coolant temperatures get up in the low 200 degrees area which I would consider normal. As soon as I resumed normal cruise speed again the temps went back down into the 160’s
Does this sound normal to everyone as this car is new to me and my other fun car is an air cooled 911 so obviously no comparison what so ever LOL
Your all a wealth of knowledge and helped tremendously with reading the forums what to look for when I bought my car. Much appreciated.
Thanks in advance
Cap

 

I thought that's what everyone on here was doing, replacing the whole assembly. It's not expensive.

 

If I an going to do that on my C4 where the housing is metal, I would agree with you. OTOH, considering this is plastic and goes through heat cycles, might as well go the extra mile and do the assembly. I just had a heating problem on my 2010 MB where the plastic valve failed and when they tried to move it to make sure it is working, it broke in their hands.

 

Capt911,

When the engine is cold, the Tachometer will have an extra color indicator around the outside. It indicates that the system is recommending a reduced engine yellow-line and redline. As the engine heats up, this ring moves up in RPM. When the engine heats more, the ring goes away.

Your thermostat is probably sticking open if the ring appears after driving a while. Watch for it to go away. If the car is under constant operation and the ring comes back again, then the thermostat is probably failing in a "stuck open" position.

My 2017 GS started doing this. The ring would appear at cold start and go away by the time I was on the freeway. Then, sometimes I would notice it appeared again when I got back off the freeway, sitting at the off ramp stoplight. I changed the thermostat and this behavior went away. Now, the ring only appears once during a drive, no matter the weather.

Thermostat failure is fairly common. There must have been a production problem, because it almost seems like the originally-installed thermostats fail, but replacements don't. Fortunately, this "stuck open" failure is better than a "stuck closed".
Another bonus is that it really isn't that hard to change.

Enjoy your new baby!
Dan

 

Perfect , thanks Dan exactly the information I needed. When I get home off my ship in a few weeks and drive it again will watch for that

 

A little history:

In the 70's car manufactures raised the engine temps from the 180's to the 190's and it was for the EPA.

They needed to raise the temps for better combustion and better cat performance.

Every hot rodder replaced it back to 180. Gained a little HP and usually gutted the cats along with recurved the distributor and reset the carbs richer and adding dual exhaust. Doing all this was a significant improvement. I know because I did it on my 76 Trans Am.

As far as AFM is concerned, Honda has played around with the amount of opening and closing of the valves for years, it was called VTEC and was a very robust system and valve timing was critical.

Honda didn't go cheap and the VTEC system in varies versions work wonderfully.

Also note that European Corvettes the AFM system works in reverse, you have to manually turn it on if you want it engaged every time you start the car opposite of American versions, most people over there didn't brother.