6.0 Swap w/new Enytropy Radiator/Fans running hot when not moving.
 

Still fixing all the little problems after doing my 6.0/4L80 Swap into my 87 Suburban. Along with the motor installed an Enytropy radiator/fan kit.
Fans come on low speed then high speed like they are supposed to.
When I'm driving and have airflow through the radiator, everything is fine, once I come up to a light or stop, temp goes up about 20-30 degrees, even if the fan is on high speed, then goes back down when I start moving. When I installed the motor I replaced the water pump and thermostat with new AC Declo parts.
Any ideas?

Re: 6.0 Swap w/new Enytropy Radiator/Fans running hot when not moving.
 

Sounds like air trapped in your system do not for get to turn the heater on to circulate the water through the heater core

Re: 6.0 Swap w/new Enytropy Radiator/Fans running hot when not moving.
 

That is what I was thinking also, going to pull a vacuum on it this afternoon at work and see if it helps.
Thanks for confirming what I was thinking.

Re: 6.0 Swap w/new Enytropy Radiator/Fans running hot when not moving.
 

Did you fill the engine from the top radiator hose dis connected from the rad?

Re: 6.0 Swap w/new Enytropy Radiator/Fans running hot when not moving.
 

I did, I filled through the upper radiator hose until I had coolant coming out of the steam hose, re-connected everything. Because my filler neck is at an angle I even jacked up the pass side of the truck to try and get the filler neck level so it would hold more coolant when I filled the radiator.

Re: 6.0 Swap w/new Enytropy Radiator/Fans running hot when not moving.
 

are you sure that the fans are blowing in the right direction?

Re: 6.0 Swap w/new Enytropy Radiator/Fans running hot when not moving.
 

Pretty sure they are, they would only plug up one way, when the fans are on high speed, I can put a rag in front of the grille and it will pull it toward the grille.

Re: 6.0 Swap w/new Enytropy Radiator/Fans running hot when not moving.
 

update: when driving to work today started getting hot when driving on interstate too. then when came to a stop still getting hot. Fans are coming on, no leaks anywhere, when I pulled over overflow tank was bubbling.
Is it possible a new AC delco thermostat is sticking?

Re: 6.0 Swap w/new Enytropy Radiator/Fans running hot when not moving.
 

If you think there is still trapped air in the system try loosening the temp sensor till you get some coolant to run out. Careful of the hot coolant.

Re: 6.0 Swap w/new Enytropy Radiator/Fans running hot when not moving.
 

I would crack the steam hose after it's been up to temp

it almost sounds like you have a leak in the system and it's not pressurizing up, or your coolant mixture is off

Re: 6.0 Swap w/new Enytropy Radiator/Fans running hot when not moving.
 

How hot is it getting? My LS2 runs 210ish on the highway on a good hot day. Sitting still in traffic 212-215ish.

Re: 6.0 Swap w/new Enytropy Radiator/Fans running hot when not moving.
 

Just used that spill free funnel thing for burping my system today. Works great. Might be worth a try.

Re: 6.0 Swap w/new Enytropy Radiator/Fans running hot when not moving.
 

Just replaced my water pump and installed a new 160* thermostat from summit. Engine was doing the same thing you are describing at idle though. Fans working and water everywhere, no air in the system. Ended up the thermostat was stuck closed replaced with a factory one from parts store and works perfect now.

Re: 6.0 Swap w/new Enytropy Radiator/Fans running hot when not moving.
 

That is what I ended up doing too. Swapped for a new thermostat and I have no more problems either.