Overheating....

[240s_are_the_best]

Okay, my overheating problem that i thought i had fixed.. well i was wrong... i dont have it fixed. Anyways I finally got the KA-T done and i am running 4psi until i get the bugs out. i had planned on running 6-8psi so i have an 8:1 FMU. I have a mishimoto radiator, stock fans, Stant thermostat, Nissan OEM waterpump ($100!! FTW!!), and new radiator hoses. i can leave the car idling all day with out it over heating (not literally all day because that would be stupid), but as i can drive it for like 10 miles and whether i stay off boost or i boost it overheats. i have jacked the front of the car up until the rear bumper hits the ground and slowly poured coolant in, shook the car, started the car and ran the defrost on high until it reaches op and then racing the engine several times, and tried every way of bleeding it i have found. it will heat up to above the H for about 30 seconds and then work its way back down to norm. is there an air bubble i cant get out? oh and there are no bubbles in the radiator, no oil in the water, and no water in the oil, and i have good compression, so im looking for something other than the headgasket as it has been recently replaced.

Thanks, Dakota

[Romeo_rus]

Do u really allow you car to get up to H????and then it works its way to normal - means you thermostat opens slowly/higher temperature - replace it with a NISMO one//

[240s_are_the_best]

only because i know it will go back down and i dont think that it is actually overheating because it goes back to normal way to fast. and ive tested the stat and it open at 180. oh and it does it the whole time im driving. it will say its heating up and then it will go back to norm. when i take the cap off slowly of course it has tons of pressure and a lot of steam and it will be low on coolant. do you think it is working air out of it and it is getting low on coolant and the steam is hitting the sender and causing the gauge to rise?

[ka-t 300]

it may be your heare core ? try by passing it by disconecting both of yout heater hoses and get a piece of cooper pipe and connect the 2 hoses together then run it for a while and see if the problem persist. good luck. i would try a different thermostat first though ive seen brand new ones not work correctly! i second the the one idea. it is a cooler running temp. thats good for boost. im running it in my car and love it.

[240s_are_the_best]

it may be your heare core ? try by passing it by disconecting both of yout heater hoses and get a piece of cooper pipe and connect the 2 hoses together then run it for a while and see if the problem persist. good luck. i would try a different thermostat first though ive seen brand new ones not work correctly! i second the the one idea. it is a cooler running temp. thats good for boost. im running it in my car and love it.

what are the symptoms of a bad heater core and where can i get one of those stats?

[240s_are_the_best]

okay im pretty sure that it is an air bubble or a bad stat... i took it out for a drive tonight and it heated up to inbetween the H and the line before the H then it cooled back down. it never got any hotter than the line before the H after that. it never actually got up to it. i think i have a bubble in the stat housing and in the heater core because the heater didnt heat up until the needle hit inbetween the H and that line and then i fluctuated between HOTTT and warm. Damn KA cooling system.....

[ka-t 300]

what are the symptoms of a bad heater core and where can i get one of those stats?

Well the heater core is like a mini radiator inside your car and it can start cloging up just like a radiator and restrict flow. so if you take your 2 heater hoses that go to it which is hooked 2 your heater core at you fire wall about 1.25 " in dia. and disconect them and find a piece of copper pipe the right diameter and just join them together (heater hoses) you will by pass the heater core and if your symptoms go away then you know its the heaer core. but as i said try a new thermostat first just get another new one from a parts house and try it you can get a bad one. to get a nismo one do a search on google. try looking at some of web sights here on nico. you will prolly have to order one. but for now just figuire out if thats the problem just go get one at the parts and try it out . even with one of those you shouldnt be going above normal operating temprature. keep us posted. it not good for your motor to go into the red (over heat) shut it off before it gets to the red !

[ghx407]

Is the jiggle valve in the thermostat in the 12 o'clock position?

[240s_are_the_best]

Is the jiggle valve in the thermostat in the 12 o'clock position?

It has been cut off and the hole enlarged. but yes the hole is at 12 o'clock

[biggie]

Some possibilities.

1. Air Bubble2. Get OEM thermo (all others have had issues)3. Could have a small leak in HG that is presurizing the coolant system under load

[C-Kwik]

An easy but anecdotal test for the heater core is to put the temp up to hot and run the engine with the heater fan on high. If it can sustain heat, it is probably fine. If the temperature drops off and blows cool or lukewarm, then there may be a problem.

it will say its heating up and then it will go back to norm. when i take the cap off slowly of course it has tons of pressure and a lot of steam and it will be low on coolant. do you think it is working air out of it and it is getting low on coolant and the steam is hitting the sender and causing the gauge to rise?

If you are getting a lot of steam when you release pressure, then it is holding some pressure. The steam is the result of the system being under pressure, which raises the boiling temperature of the water/coolant mixture. If the temperature of the coolant/water is at a temperature that is higher than the boiling point at atmospheric pressure, then allowing the pressure to escape allows coolant and water to evaporate very quickly. So the presence of steam is not a necessarily problem in that of itself.

The loss of coolant (low level) may be the result of the water and coolant rapidly evaporating when you release pressure. Hard to say without a way of measuring how much left the system.

A couple of things you might look for. Get the engine up to H and try and get out and open your hood. Is there coolant boiling out of the reservior? If not, that's a pretty good indication that you're not overheating. Try testing your temperature sensor. It could be giving you a false reading. Though it sounds somewhat intermittent which might make it difficult to confirm.

There could still be air in the system. Or as biggie mentioned, a HG failure can cause some issues. Particularly under load as cylinder pressures will be higher than at idle.

i second the the one idea. it is a cooler running temp. thats good for boost. im running it in my car and love it.

Running a cooler temperature thermostat is not necessarily better. There are of course some aspects of running cooler that are good, but bear in mind the internals of the motor were spec'd to run at a certain temperature range. With several major parts that are made of different materials, the rates of expansion are going to be different. Engineers will have carefully determined the best initial tolerances for a given operating temperature. Changing that may increase wear and tear on bearings and contact surfaces. Even oils are going to need to be the correct viscosity at the operating temperature. Lastly, depending on how Nissan set the tune, if it detects the lower temperature as "still not yet warmed up", it could run rich all the time. Depending on how much additional fuel is injected, it could cause some washing out of the cykinder walls. Not to mention, tuning could be a bit off.

Keep in mind this is more of a general statement and not specifically aimed at the KA. There are many variables to consider. But the point here is running a cooler thermostat is not necessarily a good thing.

[240s_are_the_best]

An easy but anecdotal test for the heater core is to put the temp up to hot and run the engine with the heater fan on high. If it can sustain heat, it is probably fine. If the temperature drops off and blows cool or lukewarm, then there may be a problem.

It will sustain a constant heater temp now. so i think there was an air bubble in there some where.

A couple of things you might look for. Get the engine up to H and try and get out and open your hood. Is there coolant boiling out of the reservior? If not, that's a pretty good indication that you're not overheating. Try testing your temperature sensor. It could be giving you a false reading. Though it sounds somewhat intermittent which might make it difficult to confirm.

its a newer sender. and when the gauge rises the heater gets hotter so i know it is heating up.

There could still be air in the system. Or as biggie mentioned, a HG failure can cause some issues. Particularly under load as cylinder pressures will be higher than at idle.

when i was driving it down the highway at about 65-70mph it ran the normal temp for quite a while, but when i got on backroads and was going 45-50mph it heated up but didnt over heat, and when i turned into our neighbor hood the limit is 20 and there are alot of kids so i actually went 20 and it overheated so i cut it off and let it rest a few minutes and drove it home. so do you think it could be the fan clutch or the fact that i dont have a fan shroud? but i dont think it is the shroud because it didnt do this in June when it was 90+ outside and the HG and the fan clutch are the only things i havent replaced.
Modified by 240s_are_the_best at 5:29 AM 3/2/2010

[Lonismos14]

What about this unit its full proof about getting airbubbles out thinking oabout buying one.

[240s_are_the_best]

What about this unit its full proof about getting airbubbles out thinking oabout buying one.

WTF is it??? haha

[Lonismos14]

Its a breather resevior i found it on frsport. cause i have to change my headgasket.

I also think that might be your problem faulty headgasket, my car rode fine till i put a turbo on then pop went the headgasket. I think i messed up on the torqueing pattern.

[240s_are_the_best]

i dont think mine is a hg cause it cools back down and doesnt have any signs of a blown hg. but i have to rebuild my oil pump so i have to battle the air in the coolant system yet again.

[wa-chiss]

have you tried changing the radiator cap? Start with the easiest and cheapest fixes first.

[240s_are_the_best]

The only things i havent changed are the headgasket and the and the radiator hoses but they arent clogged... i replaced the fan clutch and i am going to try it out in a little while.

[Romeo_rus]

What radiator do u have? do you have e-fans?If you have a stock radiator - get electric fans with a controller and set you e-fans to turn on at lower temperature. (e-fans are pretty cheap 2x10'' fans are $40 shipped and a controller $25 at autozone) it might solve your problem...

[C-Kwik]

It will sustain a constant heater temp now. so i think there was an air bubble in there some where.

Unlikely your heater core is clogged then.

its a newer sender. and when the gauge rises the heater gets hotter so i know it is heating up.

Don't make assumptions. I've had brand new sensors that weren't working. Test it according to the FSM to make sure.

when i was driving it down the highway at about 65-70mph it ran the normal temp for quite a while, but when i got on backroads and was going 45-50mph it heated up but didnt over heat, and when i turned into our neighbor hood the limit is 20 and there are alot of kids so i actually went 20 and it overheated so i cut it off and let it rest a few minutes and drove it home. so do you think it could be the fan clutch or the fact that i dont have a fan shroud? but i dont think it is the shroud because it didnt do this in June when it was 90+ outside and the HG and the fan clutch are the only things i havent replaced.

As stupid as this sounds, make sure you don't have a plastic bag or something blocking the front of the radiator or condensor. Even if your fans weren't there, the radiator should get enough airflow at even 20 mph to cool the radiator. As it seems that there is some change with speed, you could just have a blocked radiator. Worth a check if you have't made sure already.

[240s_are_the_best]

As stupid as this sounds, make sure you don't have a plastic bag or something blocking the front of the radiator or condensor. Even if your fans weren't there, the radiator should get enough airflow at even 20 mph to cool the radiator. As it seems that there is some change with speed, you could just have a blocked radiator. Worth a check if you have't made sure already.

humm never thought of that... i put maxima electric fans on with my fan clutch and it didnt change anything... how could i check for a crack in the hg? ive got to take the front cover off and rebuild the oil pump and if it is the hg can i reuse the head bolts?

[C-Kwik]

humm never thought of that... i put maxima electric fans on with my fan clutch and it didnt change anything... how could i check for a crack in the hg? ive got to take the front cover off and rebuild the oil pump and if it is the hg can i reuse the head bolts?

Most of the time, it can be pretty obvious (perhaps with a little testing as well). Oil or coolant burning in the combustion chamber. Oil and coolanty mixing. In some instances though, you get a crack whose effects are only apparent at high temperature and/or high pressures. It may be sealing well enough at times, but then with heat expansion, the crack grows slightly and/or the pressure overcomes the narrow passageway. You can try to test for a headgasket that leaks with heat by doing compression or leakdown tests with the engine fully warmed up (which you should be doing anyways). With the high pressure leaks, I'm not as sure how to detect it.

And I thought about it further and its also possible that an internal blockage in the radiator can cause similar effects to having the face of the radiator partially blocked. If a good number of the passages in the radiator are blocked, those channels will not get as much flow and so there would be little to no heat rejection occuring in those passages. At lower vehicles speeds, the airflow through the core may not be sufficient so that the fluid on the ooutput and might not be cool enough to absorb enough heat to keep the engine temperature at normal operating temp. As vehicle speed increases, airflow might become great enough to cool the fluid sufficiently within the channels that are flowing correctly. Just another possibility to check out.

[Razi]

What about this unit its full proof about getting airbubbles out thinking oabout buying one.

I use one of these, they work very well.

OP, if you think the air bubbles might be getting stuck at the thermostat, prop the thermostat open with two asprin pills, they'll let the air bubbles get through while you're bleeding the coolant.Then they'll melt away later, and hopefully this overheating headache as well.

[Lonismos14]

So razi with this unit do you still have to bleed the lines to get the air bubbles out or what.

How do you install it cause im buying one tonight.

[240s_are_the_best]

Most of the time, it can be pretty obvious (perhaps with a little testing as well). Oil or coolant burning in the combustion chamber. Oil and coolanty mixing. In some instances though, you get a crack whose effects are only apparent at high temperature and/or high pressures. It may be sealing well enough at times, but then with heat expansion, the crack grows slightly and/or the pressure overcomes the narrow passageway. You can try to test for a headgasket that leaks with heat by doing compression or leakdown tests with the engine fully warmed up (which you should be doing anyways). With the high pressure leaks, I'm not as sure how to detect it.

And I thought about it further and its also possible that an internal blockage in the radiator can cause similar effects to having the face of the radiator partially blocked. If a good number of the passages in the radiator are blocked, those channels will not get as much flow and so there would be little to no heat rejection occuring in those passages. At lower vehicles speeds, the airflow through the core may not be sufficient so that the fluid on the ooutput and might not be cool enough to absorb enough heat to keep the engine temperature at normal operating temp. As vehicle speed increases, airflow might become great enough to cool the fluid sufficiently within the channels that are flowing correctly. Just another possibility to check out.

okay well ive got a headgasket in the shop and im about ready to melt damn thing down and get a new ka, so i think im just going to bite the bullet and replace the hg. Can i reuse the head bolts? im 15 and i am trying to get her up and running so i can drive it when i turn 16 in 4 months... but it has 211000 miles on it and if i dont figure it out and put a headgasket on it in the next few weeks ill probably pull the engine and do a full rebuild with possible .20 over 8.8:1 dometops and I-beam rods and main and rod bearings... may do a head port also. if i drove it till it warms up and do a leak down test will that show if i have a crack in the hg? (i.e. pull the radiator cap and watch for bubbles or the coolant to overflow) oh and when i installed the radiator i took it to a local radiator shop and had it tested for flow and leaks and all was well so i am trusting his word and saying thats not the problem.

I use one of these, they work very well.

OP, if you think the air bubbles might be getting stuck at the thermostat, prop the thermostat open with two asprin pills, they'll let the air bubbles get through while you're bleeding the coolant.Then they'll melt away later, and hopefully this overheating headache as well.

haha WAIT!! ONE DETAIL I FORGOT!!! SOMETIMES THE LOVER RAD HOSE IT COLD!! that means its not circulating.. right?? could it have an air bubble around the stat and keeping it from opening up all the way?? because it doesn't run hot hot it goes almost to the line before the H. sometimes there is coolant bubbling out of the over flow sometimes the over flow is low... THIS HAS ME STUMPED!! I REALLY APPRECIATE ALL OF YOUR HELP!!! THANKS ALOT!!

[240s_are_the_best]

What radiator do u have? do you have e-fans?If you have a stock radiator - get electric fans with a controller and set you e-fans to turn on at lower temperature. (e-fans are pretty cheap 2x10'' fans are $40 shipped and a controller $25 at autozone) it might solve your problem...

Mishimoto and i have tried the stock clutch fan with the stock electric fan... dual maxima fans.. and dual maxima fans and the clutch fan. I have the fans hooked to a toggle switch (temporary) till i get it to stop over heating and then ill get thermostatic switch

[C-Kwik]

if i drove it till it warms up and do a leak down test will that show if i have a crack in the hg? (i.e. pull the radiator cap and watch for bubbles or the coolant to overflow) oh and when i installed the radiator i took it to a local radiator shop and had it tested for flow and leaks and all was well so i am trusting his word and saying thats not the problem.

Maybe. If its a situation where a certain pressure needs to be reached, then it might not. But its worth a shot. Depending on where the leak actually escapes to, you'll either see bubbles in your coolant, hear air coming from the crankcase/valve cover or air escaping from between the block and head.

haha WAIT!! ONE DETAIL I FORGOT!!! SOMETIMES THE LOVER RAD HOSE IT COLD!! that means its not circulating.. right?? could it have an air bubble around the stat and keeping it from opening up all the way?? because it doesn't run hot hot it goes almost to the line before the H. sometimes there is coolant bubbling out of the over flow sometimes the over flow is low... THIS HAS ME STUMPED!!

The lower radiator hose is supposed to be cold. At least relative to the upper hose temp. The question is how cold. If you want to check flow, just open the radiator cap with the engine cold. Start it up and let it run. Once it reaches the correct temp to open the thermostat, you should see the coolant running fairly rapidly across the upper endtank when you look down the hole.

Is the occassional bubbling in the overflow tank the coolant boiling? If so, then its definitely getting too hot.

[Razi]

So razi with this unit do you still have to bleed the lines to get the air bubbles out or what.

How do you install it cause im buying one tonight.

http://www.gtfactory.jp/cms/page.php?11Scroll to the way bottom, they got two diagrams there and helped me figure it out.Good diagram from PoweredByMax!I also bought my swirl/breather tank from them.The one that says "Highest point on engine" I just capped.I also bought their radiator hose adapter, to tee into the lower radiator hose.I'm not sure if your tank comes with a dummy radiator cap, but you need one for your radiator. That allows the air bubbles to move out of the radiator and into the tank.

haha WAIT!! ONE DETAIL I FORGOT!!! SOMETIMES THE LOVER RAD HOSE IT COLD!! that means its not circulating.. right?? could it have an air bubble around the stat and keeping it from opening up all the way?? because it doesn't run hot hot it goes almost to the line before the H. sometimes there is coolant bubbling out of the over flow sometimes the over flow is low... THIS HAS ME STUMPED!! I REALLY APPRECIATE ALL OF YOUR HELP!!! THANKS ALOT!!

Do what I said about propping the thermostat open with two pills of asprin, that should let the coolant and air bubbles circulate and get bled easier.

[240s_are_the_best]

Maybe. If its a situation where a certain pressure needs to be reached, then it might not. But its worth a shot. Depending on where the leak actually escapes to, you'll either see bubbles in your coolant, hear air coming from the crankcase/valve cover or air escaping from between the block and head.

The lower radiator hose is supposed to be cold. At least relative to the upper hose temp. The question is how cold. If you want to check flow, just open the radiator cap with the engine cold. Start it up and let it run. Once it reaches the correct temp to open the thermostat, you should see the coolant running fairly rapidly across the upper endtank when you look down the hole.

Is the occassional bubbling in the overflow tank the coolant boiling? If so, then its definitely getting too hot.

okay. and it is like really cold like its not circulating. so i think the stat is not opening up all the way. and no its not boiling its the pressure release cap opening up and letting all the stem and coolant go to the overflow and bubbling. when it was heating all the way up to the H i could hear and feel the coolant boiling in the upper radiator hose and the top tank was extremely hot and the bottom was cool

[biggie]

OEM thermo been purchased and put in yet?