[2018zl1-1le]

After cam install my IAT3 NOT 2 reading is fluctuating from like 150 to 80 I do have an expansion tank thought it would take care of any air in the system or is my pump going bad? Wondering if anyone else has experience this.
Thanks for any info

[2023_ZL1-AUTO]

Originally Posted by 2018zl1-1le

After cam install my IAT 2 reading is fluctuating from like 150 to 80 I do have an expansion tank thought it would take care of any air in the system or is my pump going bad? Wondering if anyone else has experience this.
Thanks for any info

Pinched or a collapsed coolant line hose? is the in fill on the fender tank at the top and the out flow on the bottom? enough coolant?

[2018zl1-1le]

I’ll have to check the lines

[Joshinator99]

Any air in the circuit will cause the pump to start/stop in an effort to get the air out and prevent running dry. Air in the system is very common problem unfortunately. Pump could be on the way out too.

[2018zl1-1le]

Shouldn’t the expansion tank take care of air? It sits above over the break master cylinder

[SOCAL.M6.ZLE]

Originally Posted by 2018zl1-1le

After cam install my IAT 2 reading is fluctuating from like 150 to 80 I do have an expansion tank thought it would take care of any air in the system or is my pump going bad? Wondering if anyone else has experience this.
Thanks for any info

Hey buddy, how are you tracking this? I assume a Banks iDash?
If so, I recommend watching IAT.3 as that comes directly from the TMAP sensor after the drivers side brick. IAT.2 is calculated.

Unfortunately, GM gives us no sensors or data points for the HX system, which left me, and everyone else in the dark... which is why I built this Stage.II Data Collection kit, which allows you to track your HX coolant and pressure temps in real time giving you the info you need to understand how well the system is performing, and will help you diagnose any issues.

Food for thought.

Back to your issue, I'd track IAT.3 and bled the system some more. Installing an inline GPM sensor is also helpful to diagnose the system and gives you another data point as you slowly improve the cooling system overtime.

[2018zl1-1le]

So I don’t have any kinks in any lines I can see. No air or bubbles in system but still gets really hot then suddenly drops way down doesn’t seem very consistent. I jumped the switch and let pump run for like 10 minutes. I still can’t figure out what’s causing the fluctuating in temps. Unless it is the pump slowing down at times then speeding back up. If it is the pump what’s a good alternative to replacing the stock one?
Thanks for any advice

[Joshinator99]

Originally Posted by 2018zl1-1le

So I don’t have any kinks in any lines I can see. No air or bubbles in system but still gets really hot then suddenly drops way down doesn’t seem very consistent. I jumped the switch and let pump run for like 10 minutes. I still can’t figure out what’s causing the fluctuating in temps. Unless it is the pump slowing down at times then speeding back up. If it is the pump what’s a good alternative to replacing the stock one?
Thanks for any advice

I don’t see any cooling mods in your signature. The stock LT4 intercooling is very prone to heat soak after a very short amount of time. Guys will lose 50 WHP on a back to back dyno run on the stock stuff. A small reservoir to help you get air out is a bare minimum mod. Pierburg CWA150 is a good pump to use but will require a little bit of work to make it fit and be wired properly.

[SOCAL.M6.ZLE]

Originally Posted by 2018zl1-1le

So I don’t have any kinks in any lines I can see. No air or bubbles in system but still gets really hot then suddenly drops way down doesn’t seem very consistent. I jumped the switch and let pump run for like 10 minutes. I still can’t figure out what’s causing the fluctuating in temps. Unless it is the pump slowing down at times then speeding back up. If it is the pump what’s a good alternative to replacing the stock one?
Thanks for any advice

Hard to understand what you mean by highly fluctuating. Also, just to confirm you are checking your IAT.3 (MAT) not IAT.2 correct? IAT.3 is what you want to watch, as it comes directly from the TMAP sensor.

I agree with others, in that you're making a lot of power for the OEM HX system. Time to invest in some cooling mods. PM sent.

[ZLRob]

Originally Posted by Joshinator99

I don’t see any cooling mods in your signature. The stock LT4 intercooling is very prone to heat soak after a very short amount of time. Guys will lose 50 WHP on a back to back dyno run on the stock stuff. A small reservoir to help you get air out is a bare minimum mod. Pierburg CWA150 is a good pump to use but will require a little bit of work to make it fit and be wired properly.

On a sidenote I just figured I'd add that it's amazing how prone these set ups are to heatsoak on the full stock sealed LTR set up. An external reservoir is an absolute MUST. After five dyno runs my temps stayed pretty stable and my horsepower losses were within 10 HP on all of the runs. I'm tuned, so that does come into play, due to calibration limitations within the factory flash file, but still.


No real cooling mods either.. just some water wetter and an LS3 thermostat 3 degrees cooler than factory setting.

[Joshinator99]

Originally Posted by ZLRob

On a sidenote I just figured I'd add that it's amazing how prone these set ups are to heatsoak on the full stock sealed LTR set up. An external reservoir is an absolute MUST. After five dyno runs my temps stayed pretty stable and my horsepower losses were within 10 HP on all of the runs. I'm tuned, so that does come into play, due to calibration limitations within the factory flash file, but still.


No real cooling mods either.. just some water wetter and an LS3 thermostat 3 degrees cooler than factory setting.

Yeah it’s pretty much epidemic level lol! Given how far the Camaro development team went to prevent problems with heat at the track (using the early C7 Z06 as a cautionary tale), to see them trip up on the intercooler circuit is crazy. Thankfully it’s an easy fix.

[ZLRob]

Originally Posted by Joshinator99

Yeah it’s pretty much epidemic level lol! Given how far the Camaro development team went to prevent problems with heat at the track (using the early C7 Z06 as a cautionary tale), to see them trip up on the intercooler circuit is crazy. Thankfully it’s an easy fix.

What doesn't make sense to me is why they wouldn't implement such a standard item knowing that keeping manifold air temps is absolutely paramount on a boosted application.


Sorry OP, not trying to derail the thread.