I have a 2009 base model with ~120k miles. Car is bone stock outside of headers and a vararam intake which have been on the car for several months now. I was driving it today around town and out of nowhere coolant temps spiked to 260 (maxed out the gauge) and got the coolant over temp alert on the dash. Let the car sit for about 2 hours and cranked it back up and coolant temps were sitting around 210 (normal) and stayed steady at that with about 10 minutes of idling.

I have not tried driving it around yet, what should I check before giving it another test run? Coolant levels are good, fans are blowing, oil looks good (checked for potential head gasket issue), nothing stuck in the intake, radiator looks fine and has very little debris, no signs of leaks from underneath the car.

Any help is extremely appreciated!

 

The ECT sensor is a simple 2 wire thermistor and I won’t go into how it works but if the signal wire gets shorted to ground or the sensor is bad it can max out…if you took the connector off and jumped the 2 wires together it will max out..when you just remove the connector you will see -40 degrees…if the ECM sees 260 degrees it will start shutting off injectors and the car will run poorly…did you just change the coolant ??

 

Nope, coolant has been the same in at least the 7 months of time that I have had it. Do you have any more information about the ECT sensor or a video I could watch maybe?

Would it be a solid idea to do a coolant flush as well? I work at a Subaru dealership so I have all of the tools handy and a mechanic that's more than willing to help me, he just won't be back in town until Monday of next week and obviously does not specialize in Chevrolet vehicles, nonetheless a Corvette.

 

You don’t have to be “specialized” in Corvette as they operate the same as any other car except for say the fuel system and the drivetrain with a torque tube…I’m surprised as a dealer Tech that you’re not familiar with the ECT circuit…I’m just a “shade tree” mechanic…if you want to learn this stuff visit the Scanner Danner YouTube channel…Paul is an instructor and diagnostician and has a very popular YouTube channel…he not only diagnose but instructs at the same time…his Premium channel I think is $10.00 or $11.00 a month…he has over 800 videos I believe…he has a video or two on the ECT circuit…if you are going to do the coolant do a vacuum bleed if possible so you don’t get any air pockets in the coolant system…if you have any other questions let us know…I don’t know if you’re an A or B Tech but in 6 months you will be the “go to” guy in your shop !!

 

 

I should have clarified this, but I am not a tech at all. I work in an office and like to learn here and there when I can! Got to dive into it this weekend and found out that I have the melted plugs that tons of people seem to run into (sorry I do not know the technical term for them). I had said fans were running in the initial post, but I believe that the burned plug is making it function intermittently.
I am now looking at either replacing those plugs, or replacing the entire assembly. I have heard the melted plugs typically indicate an issue with the fan somewhere so they are likely to burn up again.

With that being said, I would love some recommendations on fans to use. GM quote is $450 for the OEM fan assembly (with employee pricing, think it was like $520 customer pricing) but I feel pretty confident I can find something better for cheaper! Any advice is extremely appreciated. (Would also like to note that I have the stock radiator in)

Just want to add that I am just a 20 something year old guy who is just now getting into cars and trying to learn, If I am interpreting something wrong, or something else entirely could be the root of my issue, any help is extremely appreciated! I am sure I could hand the car off to the GM technicians at my work and let them fix it, but the only way to learn is to do it!

 

Just bypass that connector and hard wire them together. The fan isnt the issue. Even if you replace that connector it will melt again.

 

I have read some people state that doing so will push the issue elsewhere, any proven truth to that? I daily the car so just trying to find a semi permanent fix!

 

I did mine over 4 years ago. It doesn't move the problem. It removes the problem. The terminals in the connector cannot hold that much amperage without heating up and melting. When you bypass. The issue is fixed. But if you add any wire I would use a minimum of 10g. And do a good solder/ heat shrink splice

 

Fan pulls a lot of amps and over time the plug may begin to overheat. Happened to me several years back so I just spliced the wires with something similar to the link.

https://www.grainger.com/product/POL...r-14V967?gQT=1