Overheating madness

[afox1011]

Searched and searched, couldn't find anyone with the exact same problem. So here's the story
Car is a 95 240sx with a stock ka24. I blew up my radiator recently and went to work replacing stuff. Got a new oem radiator, and a new thermostat (accidentally broke my ac condensor fan as well). I re installed the new parts, I filled the rad up up with coolant and burped the air out (or at least it feels like I did), so I turn my car on and let it run with the rad cap of and the bleeder screw open and the heater on full blast. It took a while but the coolant temp finally went to normal for about a minute then it slowly climbed up high, I thought maybe if I drive it a bit it might go down. Nope, temp goes up higher a lot faster. Temp is reading as high as it will go now. So I pull back in and feel the valve cover and it's burning hot. I let it sit for a day then try again and I try burping again just in case. I let it run for a while and my gauge now won't read anything at all but now my engine is a pretty cool temperature. So after that I go to work and come back the next day to try again and this time the gauge still won't read but after sitting a while it feels really hot. (I checked for leaks and there was a minor leak in the lower rad hose but i fixed it and still same problem) I'm really not sure what's going on whether it's my gauge or my water pump or thermo, etc. or a combo of all of those things. All I know is I'm pissed off at this car right now and I'm tired of searching and searching with no results.
Don't let me down zilvia! I know you guys can help an idiot like me. Thanks in advance and apologies if my grammar/spelling isn't the best it's hard to type while you're mad. Thanks again

[Yellow4g63]

Stock fan clutch? or electric fans? Did you see the coolant start to move through the radiator when the thermostat opened up with the cap off?

[afox1011]

Stock fan clutch? or electric fans? Did you see the coolant start to move through the radiator when the thermostat opened up with the cap off?

Running stock fan clutch, and yes coolant was flowing through just fine when the thermo opened

[cotbu]

When you had the radiator cap off, bleeder screw open, and heater on full blast, did coolant come out the bleeder hole?

also check the single wire thermistor for the gauge, ka24? e or de maybe you have the wrong thermistor, stock engine wrong chassis maybe.

[afox1011]

When you had the radiator cap off, bleeder screw open, and heater on full blast, did coolant come out the bleeder hole?

also check the single wire thermistor for the gauge, ka24? e or de maybe you have the wrong thermistor, stock engine wrong chassis maybe.

Coolant did come out the bleeder screw albeit not a whole lot. Engine is a ka24de btw and I'll have to check on the thermistor

[Yellow4g63]

Did it bubble up into the over flow when the temps got too hot?

[afox1011]

Did it bubble up into the over flow when the temps got too hot?

Not to my knowledge but I'll be honest I wasnt actively looking for that. At the moment though the overflow tank is very close to being empty

[Yellow4g63]

How old is the radiator cap? Sometimes they go bad with age and won't seal up the system.

[afox1011]

How old is the radiator cap? Sometimes they go bad with age and won't seal up the system.

Rad cap I have on now is pretty old. Visibly it looks like it should work fine but I'm going to take your advice and get a new one

[afox1011]

UPDATE - went to check if maybe I put the thermostat in upside down and before I loosened all three bolts holding on my thermo housing, coolant started leaking like out of some place below the water pump. I can't exactly see where the leak is coming from ( I'm assuming from the thermo housing) but it looks like it's coming from somewhere below the housing and below the crank pulley. Doesn't seem right to me at all

[afox1011]

UPDATE #2 - just realized that I'm an idiot and that was totally normal. Carry on

[afox1011]

ANOTHER UPDATE - got a new thermostat just in case and I put it in and filled the car up with the coolant it leaked away, whilst having the rad cap off and bleeder screw open. Took a couple minutes but the coolant temp gauge went right in the middle and stayed there while at idle. But after adding a bit more coolant and waiting a few more minutes, coolant spewed out of the top of the radiator. Not entirely sure what that means but I'm assuming it just meant I added too much coolant (?).
Forgot to mention that the engine still feels pretty hot despite the temp gauge reading. Haven't had this car very long so idk if all 240s run this hot or what but nonetheless, a problem still persists

[snafupossum]

coolant coming out is normal. put the cap back on and report back when the system is pressurized.

[afox1011]

coolant coming out is normal. put the cap back on and report back when the system is pressurized.

Don't want to wake the neighbors haha, I'll have to report back after work tomorrow. Thanks for the feedback

[afox1011]

UPDATE: I'll try to make it short and sweet. Took a minute but engine temp went up to read normal and stayed there. Engine still felt pretty hot though. Drove it around, it felt fine and the temp gauge was looking good. Still a hot engine. After a little while I gave it some throttle love in second gear (sorry, lead foot) and Coolant sprayed from somewhere onto my intake manifold. Looking for the origins of the spraying right now. Still have questions though, is my gauge reading accurate and I'm just paranoid? Or is my gauge wrong and what do I need to do to fix it and the hot engine?

[anti tyler]

You need to post a picture of where your gauge is, normal is half way.

Further more what's making you think it's running hot? simply touching the metal motor in any car is going to be hot to the touch.


diagnose the cooling system problem further (if it's overheating) by taking the thermostat out and seeing if it runs warm immediately.

[afox1011]

You need to post a picture of where your gauge is, normal is half way.

Further more what's making you think it's running hot? simply touching the metal motor in any car is going to be hot to the touch.


diagnose the cooling system problem further (if it's overheating) by taking the thermostat out and seeing if it runs warm immediately.

Gauge is reading smack dab in the middle. The reason I was concerned is because not only can I not afford to replace another radiator but the valve cover and top plastic part on the top of the radiator felt hot. I know the valve cover is going to be hot but is the rad suppose to be just as hot?

[anti tyler]

Your hand isn't going to be able to tell the difference between a 160 degree valve cover and a 120 degree radiator. (Examples)


Radiant heat is going to make everything under the hood hot.


What you need to be concerned with is your dash temp sensor. If that is either reading wacky or broken and not reading at all then you could be overheating and not know it

[afox1011]

Your hand isn't going to be able to tell the difference between a 160 degree valve cover and a 120 degree radiator. (Examples)


Radiant heat is going to make everything under the hood hot.


What you need to be concerned with is your dash temp sensor. If that is either reading wacky or broken and not reading at all then you could be overheating and not know it

Alright I'll turn my attention to the temp sensor. Thanks for the feedback

[Yellow4g63]

If you sprayed coolant I'd start by check all the hoses under the intake manifold. One of them seems to have failed when the system was pressurized.

[anti tyler]

If you sprayed coolant I'd start by check all the hoses under the intake manifold. One of them seems to have failed when the system was pressurized.

Exactly, along with that, remember what I said, The best thing you can do is replace both hoses. Jack the front end into the air when cold, turn the heater on max heat, and bleed the system of air getting all of the bubbles out. Or run a swirl pot which can be had for pretty cheap these days. (It's meant to be a constant bleeder of air so you shouldn't have to bleed air out, but air pockets inside of your cooling system are 9 times out of 10 going to be your cause for overheating since now aday thermostats are mostly made to fail in the open position causing constant cooling.