Hey guys recently cammed my 01’ c5 z06 and started having issues with temps on the freeway
I did install a new water pump and a 160° thermostat, fans do spin and I did the burp procedure in case there was any air trapped in the system

Here are some pics of that my temp gauge reads

It’s reached up to 250 before I put the car in neutral and let it roll to cool down

City driving though I get 210-220

I’m stuck on what the problem could be

 

Probably the coolant doesn't have enough time in the radiator to cool off since your thermostat is always open. City driving you're turning fewer rpms fairly often so the water pump is moving the coolant slower, giving it more time in the radiator.

 

Check your radiator cap to see if it is pressurizing the system properly.

 

A few things to consider.

High temperature at highway speeds should not be a cooling fan issue. They are not normally running.

Are all 3 parts of your air dam below the front bumper in place? The C5 is a bottom breather and needs the center air dam to direct air through the cooling system.

A 160 degree or stock thermostat has no influence on coolant temperature at the temperatures you are showing. Both will be wide open.

 

DO the Factory Service Manual procedure to get air out of the heads.

 

If the coolant is moving through the radiator faster, it’s also running through the engine faster. As in all heat exchangers, the faster the fluid flows the more efficient they become.

The question here is there sufficient air moving through the radiator fins.

Is the air dam in place, and has the radiator been checked for dirt/debris, are the fans actually turning off at speed…

 

If you do some research, you'll find this is physically impossible. Any time coolant is running at too high of temps, engineers invariably speed up the water pump. It sounds more like trapped air in the system, a filthy A/C condenser, a bad t-stat, an UD balancer, missing radiator air dam(s), missing radiator cover, or any combination of the aforementioned problems.....

 

Thermostat controls minimum engine temp - cooling system controls maximum. I think you might be thinking of the old stories about people removing thermostat - in some cooling systems it could be an issue, in others not.

In this case, if he installed a 160 t-stat and the fans are still set at the factory settings, he will see over 200 in traffic/idle. If it is a correct thermostat (physical construction) for the car.

With a cam just being put in, I immediately think bleeding, air dam, was a tune required for the cam that was not done, rag left in the engine? There are a lot of possibilities here. Some simple diagnostics with a temp gun on each side of the t-stat and at hoses will tell a lot. Also, there's a chance the temp sensor is on the way out. Have to keep that possibility in mind and another reason for a 15$ temp gun from Amazon. Would like to see what the digital temp reading is as well.

If the car sits at idle and hits 250, it's obviously not an air dam, it's fluid, fans, obstruction (internal or external).

If it's only when driving on the highway, we are back to air dam, sucked up a bag, dirty fins, rag left in engine. Driving on the highway, fans would not be needed to keep it cool.

 

after tonight it seems like it was my cap, wasn't paying attention to my temps and it reached red line and smoke was coming from the hood. I pulled over and noticed coolant all over the reservoir and nothing from the heads.

 

Occam’s Razor…