New Rebuilt KA overheats!?!?

[Forum_Lurker]

Okay so i have done a rebuild on my KA. New water pump, thermostat, new koyo aluminum rad. I caped off the heater hoses on the intake manifold that goes to the back and the other heater hose that runs up from the thermostat to the top on the intake manifold.

I made sure the engine was bled properly, even took out the thermostat to make sure it was on right. Rad. is not clooged either... New e-fan set up, works fine....

It overheated on me a few times but i always shut off the engine as soon as it did.... I have even gone as far as replacing the temp sensor thinking that was screwed up.

Anybody have problems capping off those heater hoses on the intake manifold?

Any ideas? Thanks for reading....

[gunluvS14]

i have a feeling you probably still have a huge air pocket in the cooling system

[Forum_Lurker]

I used this and i have bleed the coolant a few times making sure there is no air.... These bad boys are the best to get air out of a cooling system...

[nissanfanatic]

I guess the only things that would cause this are not turning the heater on fully or a headgasket sealing issue? I actually just connected the two heater core hoses together to bypass my heater core all together. It didn't work anyways. Now I need to go in there and remove the core itself for weight savings.

[alan-n]

Are water temps climbing way beyond normal, or is it being pressurized? Its possible thermostat can be bad but if the water temps are normal than you have your answer, leaking HG.

[Forum_Lurker]

The temp climbs beyond normal... I am using a new rad. cap as well thats higher pressure...

When i pulled the thermostat to make sure it was on right(which it was), I replaced it with another OEM one that i had laying around. I bled it again with the heater on, and the bleed funnel.

I just do not see oil in the coolant vice versa..... Oil is not mixing with coolant when i look at the oil, no signs of mud or milk shake.

I do not understand how it could still be an HG...

I think best way to make sure HG is leaking is a coolant system vacuum test.. see if it holds pressure over night....

BAH!

any other ideas guys?

Thanks for everybody's help! =)

[BILLFISHER21]

the best way to test the hg is with a block tester and it will tell you if you have exhaust gas present in the cooling system. Co2 in cooling system mean leaky hg or cracked head/block.

[knate]

If you capped off all those lines maybe the water just isn't flowing everywhere. Maybe it needs to be looped instead?

[hernameissilvia]

I'm having the same problem, but with my SR. I've eliminated the heater core all together (removed), and installed a greddy style intake manifold. The engine was bought from Mazworx and they installed the Apexi MHG, ARP studs and HKS cams before I picked it up. The engine has been in the car for probably a 1.5yrs now (mostly due to no funding for the project) and I can't figure out why it overheats. It seems to be fine when at idle, but as soon as it's driven, the temps shoot up and coolant boils out of the overflow. I've flushed the radiator and block to make sure there was no blockage. Brand new thermostat and it's good (Ive stove tested it). New radiator cap was tried. Compression test its good, right around 147-150 for all cylinders. I've tried draining and refilling the coolant multiple times to make sure the air is out. Is it possible the hoses are collapsing when heated? I did a block test awhile back and it came back negative, but maybe I'll try it again.

Forum_Lurker, did you ever find a solution?

[240dragon]

Possible that the electric fan is grounding or shorting out, My fan relay was shorting out because of bad placement causing me to over heat. just a suggestion.

[S14eva1]

raise the car or put it in a steep incline,top of the radiator,leave cap off....squeeze the top hose while engine is runnin and watch the bubbles rise up.It may take up to 10-20min. before all bubbles are gone

[hernameissilvia]

The OP is over a year old, I was just wondering if he ever found a solution.