Alright maybe there is a blockage? I brought it up to temp this morning with the front end raised really high to try and bleed some air but I also put a thermometer in the radiator to see what the temps were. Whats odd is that the temp in the radiator never climbed and stayed around 80 degrees but I can fill heat in the top hose and the gauge is reading around 250.

I've ordered a new thermostat from Summit to try that option and I'm not sure the one I got locally was the right one.

Just so I can get confirmation, I have the hoses going the the right inlets right? The top one goes in, well the top one, and the bottom returns back to the lower radiator.

It sounds like your thermostat is not opening or you have an air pocket. I can’t remember if you can install an LS thermostat backwards but if you can maybe that is what is going on...

Hoses are correct.

Don

Did you just start having this issue or is this the first start up and break in? Does the lower hose ever get hot?

It's been doing this since I got it up and running. I'm going to install the correct thermostat tomorrow and see if that helps, If not, I'm going to run some food coloring through the system and see if the water is actually circulating through the motor. I figure that will be a good indicator if the water pump might be bad. Just trying to eliminate all the possibilities one by one.

Ok so how many miles have you really driven it? Start the engine and make sure the bottom Hose gets hot. If it doesn’t the engine isn’t to operating temp or the thermostat hasn’t opened. The boring gauge will read that the engine is hot but until the thermostat opens up and the system bleeds you won’t get a accurate reading.

Again where do you live ?

Sorry missed that question earlier, I live in Los Angeles.The motor was from a 2012 Camaro with around 19k miles and I've probably put right around 500 miles on the car since I've had it up and running.

Alright installed the correct thermostat, put it all back together and filled the coolant through the top hose slowly until it ran out the top of the radiator and with the car elevated. Turned on the car and let it warm up for a good 10-5 minutes and the gauge still climbs all the way to 250. The fans come on around 220 which I think is too late and the bottom hose was col the entire time so I'm assuming the thermostat never opened up. I let it run showing 250 for a good 5 minutes before shutting it off to be safe. Should I try to let it run for longer and see if the thermostat does open up? I just don't want to overheat the engine.

Oh, also I'm running Vintage Air's frontrunner setup and it's all brand new including the water pump and radiator. The 500 miles or so I've put on the setup has been with all new parts.

Keep letting it run. The lower hose needs to get hot. Have the heater running as well

Alright, I'll try again this evening. I can't run the heater as I don't have the actual vintage air system hooked up yet.

Ok, ran the car for over 20 mins and it never seemed like the thermostat opened up because the lower hose still never really got hot while the top one did. The lower one seemed to slowly start warming but not sure if thats just the residual fluid in the radiator mixing from the top to the bottom and not circulating through.

I feel like running it for 20 mins should be long enough for it to come up to temp all around and kick open the thermostat, am I wrong?

Thanks everyone for their patience as well. By now I've drained and filled the radiator about 10 times. LOL.

Put a manual temp sensor in it to verify. Maybe you’re chasing your tail.