trouble bleeding coolant system - fresh S52 swap - please help

[Sh3rpak!ng]

Everything is working and motor is running, but I can't get the coolant to bleed. I have aux gauges so I can keep a close eye on temps. I filled the system with heater controls on full. When the car runs, it gets up to temp and the thermostat doesn't open, the temp just keeps climbing.

Everything is new. The motor was just built from the block up. Stewart pump, koyorad 48mm aluminum radiator, 16" spal pusher, new hoses, new expansion tank, aluminum thermo housing, and a behr 88c thermostat.

First I thought it might have been a bad thermo so I exchanged it for another new one, same issue.

The vents were initially blowing cold, now they blow warm, even with the motor at ~215-220F as indicated on the aux gauge.

I've revved it a little, driven it around the block (which has some steep inclines and declines) and it doesn't seem to help.

Yesterday, I got it up to temp, then it started getting hot, so I shut it down. As it was cooling down, I heard the thermostat open with a ping, coolant drained from the expansion tank, then "click" it shut again.'

Lower rad hose is not getting hot.



Any ideas??? I'm getting frustrated. I've never had this kind of trouble while bleeding coolant before.

[m3boost]

remove radiator cap... detach top radiator hose. Lift hose and add coolant through that hose. Go slowly, as coolant is going into the head.. keep adding until you see coolant spilling out the radiator opening... quickly reattach hose.. trust me, your system is fully bled... turn it on and let it get to operating temp.. just keep an eye on the gauge.. after being on for about 15 minutes, shut the car off and just wait until the next day when its completely cooled. remove cap an add coolant if needed.. you're done.

[mpowerful]

Do have your heater hoses hooked up backwards? Makes flow terrible and harder to bleed.

[Sh3rpak!ng]

remove radiator cap... detach top radiator hose. Lift hose and add coolant through that hose. Go slowly, as coolant is going into the head.. keep adding until you see coolant spilling out the radiator opening... quickly reattach hose.. trust me, your system is fully bled... turn it on and let it get to operating temp.. just keep an eye on the gauge.. after being on for about 15 minutes, shut the car off and just wait until the next day when its completely cooled. remove cap an add coolant if needed.. you're done.

Should I just drain the whole thing and do this?

I think it's full now, but I'm not convinced its fully bled. The heater blows hot, and while driving it sits about 190F where it should. But it still pops up to about 210F like after driving up a steep driveway - low speed and heavy load on motor - and doesn't really drop quickly even with the fan on.

Do have your heater hoses hooked up backwards? Makes flow terrible and harder to bleed.

They're correct. Bottom heater hose to head, top heater hose to metal "spider" hose

[Sh3rpak!ng]

So, I grabbed an IR gun off amazon to set things straight and determine what exactly is going on (also this thing is just handy to have and inexpensive)

Looks like either my water temp gauge or sender is faulty. I was measuring ~190 at the sender while the gauge was displaying ~210-220.

I measured thermostat temp, rad inlet, rad outlet, aux fan switch and temps at the rad outlet with the aux fan on and off. Everything measured about the temperatures I would be expecting for their respective positions (the koyorad 48mm aluminum radiator seemed to be doing it's job! with the aux fan on for only 10 seconds, I read 130F at the rad outlet). Didn't read a temp over 205F at any point even while the car was sitting in 90F heat idling for about 10 mins... the aux fan cycling on and off appropriately.

So I guess everything was probably working from the beginning. Never thought the aux gauge was reading high. Now off to troubleshoot that!

Thanks for the help