New thermostat overheating

[MAGAlomaniac]

Back up a minute... why was the coolant temp sensor changed? Are we sure that that new one is reporting correctly?

I changed it because it wasn’t coming up to temp at all and the fan would come on.

 

[MAGAlomaniac]

I changed it because it wasn’t coming up to temp at all and the fan would come on.

I think it’s reading correct because when it says the engine is too hot the top hose is a lot cooler than the bottom one. To me that means the thermostat is stuck closed.

 

[MAGAlomaniac]

You can’t just burp these out at standard idle. You need a few good random mid range revs to get the heater lines totally purged.

Ok, I’ll try that. Would the air come out just by driving it or do I need to bring it up to temp with the reservoir cap off?

 

[Doubeleive]

Ok, I’ll try that. Would the air come out just by driving it or do I need to bring it up to temp with the reservoir cap off?

been seeing a lot of bad thermostats out there particulalry for this gen, It comes up at least every couple weeks on here. GET that oem one in.

 

[buckwild27]

Here's a few options. If the thermostat is the issue and you want to run a cooler temp and not have to do ecm tuning.

Katech 174 Degree Gen 5 LT Thermostat

For LT1/LT4/LT5/L83/L86

katechengines.com

If you want to get away from this generation of thermostat you can get this housing and run the previous generation thermostat.

DMS Billet Thermostat Housing w. LS3 Style 160 Degree Thermostat - Gen V LT

DMS Billet Thermostat Housing w. LS3 Style 160 Degree Thermostat - Gen V LT (DMS160LT)

www.montmotorsports.com

And in the off chance it's not the thermostat you can remove the thermostat and run it without to determine if a head gasket is leaking. This will throw a check engine light because the thermostat is out. But you will know you have a bigger issue if engine over heats with out a thermostat. You will have to drive it to determine this.

 

[89Suburban]

Ok, I’ll try that. Would the air come out just by driving it or do I need to bring it up to temp with the reservoir cap off?

Do the original burp with the cap off.

 

[StinkyLinky8]

I feel like I had the same issue recently. For a while, I noticed the engine failing to come all the way up to temperature and maintain that temperature sometimes it would but it would back down. Replaced the thermostat and it was coming up to temperature and holding, but didn’t seem like it was opening quick enough as I would get on the highway and wide open throttle and it would start to overheat and then suddenly the temp would go back down to normal I went back to the auto store and got another thermostat and replaced it and since then it has been fine.

 

[Doubeleive]

optionally you can test the existing thermostat in boiling water....

 

[yugrus]

I had good luck with the vacuuming tool that pulls air out of the cooling system before filling it with coolant. It has worked every time so far, no air pockets. I will use it again soon when I replace the pump, the hoses, etc. as a preventive maintenance.

 

[Doubeleive]

my money is on bad thermostat, 99% percent of the time that's what it is when people use a aftermarket on these k2's
not sure why other than there seems to be a crap-ton of bad ones out there. It gets posted on here all the time.......