can't solve my overheating issue

[bobbo]

Are you able to bleed from the bleeder on the top of the engine above the injector harness? Mine was plugged causing an air lock.

[Black BNR32]

thanks dragon and bruizer. any way i can 'pressure flush' the system at home with a garden hose (to check blockages)?

egts - not sure

build has maybe 5k kms? not sure as it was done by the previous owner

tried bleeing with front up and level

bleeding...well...i tried a ton of different things. lets just say:
-fill though rad until collant comes through the bleeder
-lots of squeezing/burping of the rad hoses
-keep the level way above the engine(coke bottle funnel)
-bring it up to temp with the rad cap off and funnel in, pull the bleeder screw a few times, more burping...
-keep in mind i have the heater core bypassed. is there a valve anywhere in the heater system? those hoses are staying cold too.

[Dragon Humper]

If you pulled the thermo and the flow didn't skyrocket then you have a problem with the pump or you have a blockage somewhere. The coolant should look like a fast moving stream when you look through the cap hole and the thermostat is missing.

Fast moving coolant is just as bad, I have had cars overheat in the winter time because there was no thermostat and the water was just moving too fast and not getting a chance to cool off in the rad core.



Jon.

[Bruizer]

What's your EGTs like? How are you bleeding the system? Front end lifted or car level? Fresh rebuild or been driving for w while and it now happens?

[Black BNR32]

Guys, I need a hand with an overheating issue I'm having.

set up:
rb26
new rad cap (13psi)
koyo rad
dual puller fans, on all the time
tried a couple different thermostats
n1 pump
no ac or heater core (bypassed it for testing)
stock oil cooler
50/50ish mix

symptoms:
boiling over approx 5-10 minutes after reaching operating temp
high oil temps (110+, stock gauge though)
lower rad hose stays colder than i think it should be. almost completely cold.

tried so far:
-flushed and drained system - looked good and clean
-pulled rad and flushed it with the garden hose, pretty positive theres no blockages
-replaced rad cap and thermostat
-bled/burped the crap out of it many times with the 'coke bottle on the rad' method. i'm pretty confident in my bleeding, but air in the system is still an outside possibilty
-pressure tested system to 15psi

other thoughts:

I'm not 100% positive I have good water pump flow. The only test I've done is to look for flow in the rad cap hole as the system comes up to temp. i'm just not sure what's normal. Are there any other good tests to measure pump output? It spins freely and doesn't leak...Is it common to damage the wheel/blades on the inside? I tried running with no thermostat with hopes of seeing flow easier, but didn't really help. i'm thinking about pulling the pump next .

i haven't ruled out headgasket, but it seems unlikely as i'm not getting the usual systems like mixing oil and coolant, poor running, lots of bubbles in the coolant, white smoke, etc. i haven't done a leak down test yet.

Could high oil temps be a cause? I assume its just an effect.


thanks!