can't solve my overheating issue

[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!

[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?

[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.

[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.

[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]

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.

-fill though rad until collant comes through the bleeder

......

[Bossman]

-keep in mind i have the heater core bypassed. is there a valve anywhere in the heater system? those hoses are staying cold too.

Did the over heating occurred after you did the heater core bypass or you did the bypass trying to solve the problem? I haven't looked at how the cooling system works but I was watching one episode of Canadian Rally on TSN and one of the cars in the race had to pull out due to overheating, it turned out the problem was that the team had the engine replaced the night before and the heater hoses for the heater core was reversed. Perhaps someone can explain this better.

[Black BNR32]

It occured before. there are 2 hoses that go through the firewall for feed and return, and i connected them. i did it to be sure i wasn't hitting a blockage in the heater core.

[dustyGTR]

I work at a Ford dealership we have a special tool that we dust off once in awhile for strange overheating concerns, it is made out of clear plastic and is installed inline with the upper rad hose it has a built in flow guage,pressure guage and temperature guage and obviously you can see the flow as well since it is clear. When did this concern first occur, was it after you had the cooling system apart? Airlocks are a major concern and can be difficult to get rid of on some cars the vacuum filling tools are one of the best ways to reduce airlocks several companies make these you hook up an airline and suck all the air out pull a vacuum and let it draw the coolant in. Certain vehicles the impeller can come loose off of the water pump shaft or the impeller falls apart (so no flow) this happens more often on pumps with plastic impellers, have not heard of it on an RB. You also mentioned bypassing the A/C did you change belt routing at all? I have also seen people convert motors from v-belt to serpentine systems etc or changing belt routing and spinning the pump backwards, water pumps generally are designed to spin in one direction only. My car is not with me you also mentioned a new 13 psi rad cap(is that what are cars normally run?) this seems low 16psi is quite common on many cars and the lower the pressure the lower the boiling point. As far as headgasket goes there are chemicals you can put in the coolant that change colour in the presence of combustion gasses (I have never used) or you can just hold a gas analizer over the open rad cap or resevoir.

Good luck let us know what you find!!
Marcus

[Bossman]

It occured before. there are 2 hoses that go through the firewall for feed and return, and i connected them. i did it to be sure i wasn't hitting a blockage in the heater core.

I guess you can rule out the by-pass. Did you say you replaced the radiator? My wife's CRX was overheating on idle and it was the radiator. From the engine side all the fins were in place and looked fine but after I took the radiator out the fins on the front side of the car were half gone. I know it was the radiator because when I had the heater on hot the temperature went down, and I also had a new thermostat replaced before I replaced the rad. Another someone personal experience is to make sure you have the new thermostat placed in the correct direction. I remember my dad had a overheating problem and it was worst after he replaced the thermostat, after he flipped the thing than it was fixed.

[Black BNR32]

the rad is fine, the thermostat only fits in one direction

[Black BNR32]

I work at a Ford dealership we have a special tool that we dust off once in awhile for strange overheating concerns, it is made out of clear plastic and is installed inline with the upper rad hose it has a built in flow guage,pressure guage and temperature guage and obviously you can see the flow as well since it is clear. When did this concern first occur, was it after you had the cooling system apart? Airlocks are a major concern and can be difficult to get rid of on some cars the vacuum filling tools are one of the best ways to reduce airlocks several companies make these you hook up an airline and suck all the air out pull a vacuum and let it draw the coolant in. Certain vehicles the impeller can come loose off of the water pump shaft or the impeller falls apart (so no flow) this happens more often on pumps with plastic impellers, have not heard of it on an RB. You also mentioned bypassing the A/C did you change belt routing at all? I have also seen people convert motors from v-belt to serpentine systems etc or changing belt routing and spinning the pump backwards, water pumps generally are designed to spin in one direction only. My car is not with me you also mentioned a new 13 psi rad cap(is that what are cars normally run?) this seems low 16psi is quite common on many cars and the lower the pressure the lower the boiling point. As far as headgasket goes there are chemicals you can put in the coolant that change colour in the presence of combustion gasses (I have never used) or you can just hold a gas analizer over the open rad cap or resevoir.

Good luck let us know what you find!!
Marcus

thanks dusty

this first occurred after it came out of storage this winter (no opening of the system). and it had been damn cold. i was a little worried that i had freezing in the system, but as i understand the rad and heater core are the most vulnerable to freezing damage and they check out fine.

i've seen those vacuum filling tools in action and they are slick.

the impeller coming loose or being damaged is a possibility, but i'd like to think its unlikely.

the ac has been removed

i will double check belt routing

13psi rad cap is standard

i plan on checking for blockages once more and then pulling the pump

[Black BNR32]

pretty sure the pump aint supposed to do this

http://s102.photobucket.com/albums/m109/bryn1123/?action=view&current=49377f33.mp4

chalk one up for an N1 impeller failure

[cortexx]

Sounds like a seeping head gasket (cylinder to water jacket) to me , although , how long did you have the rad hoses off for during your build ? might have a mouse in there i have seen that before too . Mouse carcass is very bad for coolant flow...

[cortexx]

ooops posted just after you

That N1 pump looks different to my N1 pump

I got one from one of the vendors on here , ill post a pic when i get home.

pretty sure the pump aint supposed to do this

http://s102.photobucket.com/albums/m109/bryn1123/?action=view&current=49377f33.mp4

chalk one up for an N1 impeller failure