95 ka24de overheating

[yoinkAzenki]

my s14 started overheating about a month ago and it still does every week or so and i still dont know why. temp gauge starts to rise and idle raises over 1k. overflow tank is also full. i've had overheating problems back then but i fixed it and now its doing it again. heres a list of what i've done the past month:

no coolant leaks anywhere
no blown headgasket, checked oil, no white smoke, compression good
water pump was change less than a year ago and its not leaking
radiator was also changed to an aftermarket aluminum radiator less than a year ago
thought there was air bubbles so i bled the system but it was fine for a week and it overheated again
changed thermostat to nismo thermostat
radiator hoses were change to new ones
temperature sensor was changed but with a used one
radiator cap was changed but with a used one
also found out tonight when i was overheating again that my heater was blowing cold air when i turned it on

so any ideas on why im overheating?

[LA_phantom_240]

Do you have a real gauge or stock? Stock gauge = weaksauce and lies.

[surreybc]

my s14 started overheating about a month ago and it still does every week or so and i still dont know why. temp gauge starts to rise and idle raises over 1k. overflow tank is also full. i've had overheating problems back then but i fixed it and now its doing it again. heres a list of what i've done the past month:

no coolant leaks anywhere
no blown headgasket, checked oil, no white smoke, compression good
water pump was change less than a year ago and its not leaking
radiator was also changed to an aftermarket aluminum radiator less than a year ago
thought there was air bubbles so i bled the system but it was fine for a week and it overheated again
changed thermostat to nismo thermostat
radiator hoses were change to new ones
temperature sensor was changed but with a used one
radiator cap was changed but with a used one
also found out tonight when i was overheating again that my heater was blowing cold air when i turned it on

so any ideas on why im overheating?

faulty /wrong stat or air around the stat. the stat sits in water and opens at set temperature. if your rad was clogged , the water around stat might be cool. too(guessing) . run without the stat and see what happens.

first, though, park car on steep hill and run engine with rad cap off. shake the car by sitting on bumper. heater on.

You can change the thermostat without removing the fan etc but you need a small ratchet wrench with small extension to get the bottom bolt.

http://img341.imageshack.us/img341/4262/thermostat035tw7.jpg
http://img525.imageshack.us/img525/3727/thermostat030md9.jpg

[s13boy89]

take out your thermo it wont overheat

[silpena]

maybe u should put a new cap and try it again. I had the same issues one time. Try it out and see what happens. The cap can be bad.

[yoinkAzenki]

Do you have a real gauge or stock? Stock gauge = weaksauce and lies.
its the stock gauae but it works fine
faulty /wrong stat or air around the stat. the stat sits in water and opens at set temperature. if your rad was clogged , the water around stat might be cool. too(guessing) . run without the stat and see what happens.

first, though, park car on steep hill and run engine with rad cap off. shake the car by sitting on bumper. heater on.

You can change the thermostat without removing the fan etc but you need a small ratchet wrench with small extension to get the bottom bolt.

http://img341.imageshack.us/img341/4262/thermostat035tw7.jpg
http://img525.imageshack.us/img525/3727/thermostat030md9.jpg
i've already done this. everytime i think theres air i bleed it and it will be fine for a week and start to overheat again
take out your thermo it wont overheat
i havent done this but i heard its not a good idea
maybe u should put a new cap and try it again. I had the same issues one time. Try it out and see what happens. The cap can be bad.
the cap was off a new radiator my bro wasnt using but i guess i could buy a new one

[((sr)) kelly]

take out your thermo it wont overheat


NOOOOOOOOOOOOOOOOOOOOOOOOO

why do people do this??? there is a reason the thermo was in there...


the cylinder walls HAVE to warm up before the coolant can get into the water jackets.... if you have coolant constantly in there then youll have the outside of the wall ALOT cooler then the inside of the wall... this warps the cylinder walls and causes you to loose compression.

the iron blocks is probably a little more tolerant, but i wouldnt do it

[ChicagoS14]

YOu sure you have no air coming into the system? And change both temperature sensors to brand new ones, also double check if your fan clutch and fan kick on, perhaps the fan isnt working. Also did you use OEM or some off brand stuff from a parts store? My buddy went through 3 thermostats from a parts store before he found one that worked, could be your culprit. Check the cap as well but Im also curious about your water pump because if its one of those part store brands could be another issue, I never trust that shit, it breaks way too often.

[surreybc]

have you run without the stat?? your interior heater is blowing cold air. thats a pretty specific symptom. the stat is what opens up to allow the hot water to move to heater.

[projectRDM]

First off, always use an OE thermostat. The OTC stuff aren't the same size spring or valve. Next, clip the jiggle valve off with a pair of wire cutters, then drill the opening out an extra 1/16". That allows for more air passage without increasing water flow through the unit when closed. Now bleed it again.

The cold air inside is a definite sign that the thermostat is closed, you can also grab the lower radiator hose, if it's cold at the engine side then it's not opening. I've done cars that were fine for a few days then got hot again, and some that bled once and never had a problem again, every car is different. Running without a thermostat though is stupid, the engine has to reach operating temperature to achieve the correct tolerances. And trusting the OE gauge is stupid, there is no common point where it registers too hot until the engine has already sustained damage.

[Indolent]

didn't see you mention anything about your clutch fan, make sure that has resistance/working properly too

Bleed system, jack car up high, heater full blast, use funnel..put a little extra coolant/distilled water so while you're squeezing the upper/lower radiator hoses it doesn't spill out and helps getting more air out the system

don't forget about that bleeder screw on the intake manifold (ka24de)

I found my problem of overheating was having no thermostat (just bought the car/found out it didn't have one after overheating problems), put a nismo thermostat on there, no problems so far, but i just put it on a few days ago

[surreybc]

I say bleed it properly. Make sure heater is on when you bleed it. maybe get it pressure tested for leaks.

[yoinkAzenki]

YOu sure you have no air coming into the system? And change both temperature sensors to brand new ones, also double check if your fan clutch and fan kick on, perhaps the fan isnt working. Also did you use OEM or some off brand stuff from a parts store? My buddy went through 3 thermostats from a parts store before he found one that worked, could be your culprit. Check the cap as well but Im also curious about your water pump because if its one of those part store brands could be another issue, I never trust that shit, it breaks way too often.
both sensors work but when i get money ill buy new ones
both fans also work
i have a nismo thermostat and the car runs a lot cooler when its not overheating
water pump was bought from autozone i think its duralast brand
have you run without the stat?? your interior heater is blowing cold air. thats a pretty specific symptom. the stat is what opens up to allow the hot water to move to heater.
never ran without thermostat and dont plan to
First off, always use an OE thermostat. The OTC stuff aren't the same size spring or valve. Next, clip the jiggle valve off with a pair of wire cutters, then drill the opening out an extra 1/16". That allows for more air passage without increasing water flow through the unit when closed. Now bleed it again.

The cold air inside is a definite sign that the thermostat is closed, you can also grab the lower radiator hose, if it's cold at the engine side then it's not opening. I've done cars that were fine for a few days then got hot again, and some that bled once and never had a problem again, every car is different. Running without a thermostat though is stupid, the engine has to reach operating temperature to achieve the correct tolerances. And trusting the OE gauge is stupid, there is no common point where it registers too hot until the engine has already sustained damage.
im using a nismo thermostat. as far as clipping and drilling ill try it
every time it overheats i check the hoses. most of the time the top hose is really hot and the bottom hose is warm/cool so i bleed for air bubbles
didn't see you mention anything about your clutch fan, make sure that has resistance/working properly too

Bleed system, jack car up high, heater full blast, use funnel..put a little extra coolant/distilled water so while you're squeezing the upper/lower radiator hoses it doesn't spill out and helps getting more air out the system

don't forget about that bleeder screw on the intake manifold (ka24de)

I found my problem of overheating was having no thermostat (just bought the car/found out it didn't have one after overheating problems), put a nismo thermostat on there, no problems so far, but i just put it on a few days ago
both fans work. also did the whole bleeding system thing just like that everytime it overheats. its fine for a week and overheats again. also using a nismo thermostat
I say bleed it properly. Make sure heater is on when you bleed it. maybe get it pressure tested for leaks.
bled the system numerous times the proper way. have yet to get it pressure tested but definitely no visible leaks

[Bigsyke]

have you run without the stat?? your interior heater is blowing cold air. thats a pretty specific symptom. the stat is what opens up to allow the hot water to move to heater.


Thats 100% wrong. The coolant moves from the engine to the heater then routes back into the engine if thermo is closed. If your heating isnt getting heat then inspect the linkage that controls the heater.

[surreybc]

Thats 100% wrong. The coolant moves from the engine to the heater then routes back into the engine if thermo is closed. If your heating isnt getting heat then inspect the linkage that controls the heater.

I was thinking of my old car. this is the 240sx manual

http://i36.photobucket.com/albums/e25/vancouverbc_2008/jjjl004.jpg