Why do I keep overheating? even with tuarus fan - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

driftkid316 · 08-09-2006, 12:55 AM

i put a whole jug of 50/50 premixed antifreeze coolant in and filled the rest with water. have a tuarus fan on high speed at all times. but the damn thing still overheats, not so much on the freeway cause so much air. but when city driving and obviously parked, it over heats pretty fast. i know the guage isnt messed up cause when i pop the hood i can hear it boiling. the radiator seems to be ok, not too much rust. what could it be?

Xren17 · 08-09-2006, 01:43 AM

Did you jack it up and bleed it through the bleeder valve? I had the same problem and it was fix after bleeding it.

driftkid316 · 08-09-2006, 01:57 AM

im sorry, i dont know how to bleed it. how do i go about doing that? btw, i have a 90 s13 sohc

daryl337 · 08-09-2006, 02:09 AM

There are many things that can cause an over-heating problem... but just by saying that your fan actually turns on eliminates about 50% of them.

Try a new thermostat... 80% of the time that is the problem. If it isnt that, look for soft hoses, as well as flush your entire system a few times to make sure that there isnt rust in the BLOCK that is blocking anything. If it is not that, then look into the water pump cavitating.

BTW.. bleeder valves USUALLY are on the intake manifold or the head (forgot where it is on the ka24e)... In any situation, it is going to be up high.

blu808 · 08-09-2006, 02:24 AM

What most peeps dont realize is that when the rad cap is off, and you fill it up, it is just filling up the rad. One way to think of it is if your thermostat is a plug in you radiator. and when it finally opens after about 15 mins of idle, then it starts circulating coolant through the engine water jackets. I would recc that you start the motor completely cold. with the rad cap off, then keep feeding it water for 30 mins. after letting it run for 15 mins the thermo will open and suck up the water. Just keep feeding it, until there are no more air bubbles. Air is the main cause of overheating. Just think of air as your bin lauden. Get it all out. then before it starts gushing out cap it.

make sure before this you have your coolant res filled. that way it wont suck up any bin lauden air.

If that doesnt work. you may try changing your t stat. then your water pump. if that fails. do a leak down test and see if you have a blown cyl, or h gask.

Poo FTW.

driftkid316 · 08-09-2006, 02:24 AM

if it is the thermostat, wouldnt it just make my guage read wrong and the car would still not really overheat?

blu808 · 08-09-2006, 02:26 AM

no. your coolant temp sensor is in the water neck after the t stat. so if it failed it wouldnt even be close.

KA, sr, rb, vg same stuff.

daryl337 · 08-09-2006, 02:48 AM

Well, basically think of it like this. Your water pump is pumping away like the little pump it is... and from there... the water can go to two places... 1) it goes to your radiator where it is cooled... or two... it goes out your coolant bypass line and recirculates throughout the motor. When the thermostat is closed, no cool water comes from your radiator... and to prevent any pressure from building up in the radiator... the water is recirculated in the block. As the recirculated water heats up.. the thermostat opens up.. and lets the cooled water come in.

Now... what does this mean for you? A sticky thermostat keeps your radiator from giving you cool water. =D But like I said.. also check for collapsing hoses... and do a good flush just to make sure you are getting proper flow.

08-09-2006, 12:55 AM	#1
driftkid316 Zilvia Member Join Date: Apr 2005 Location: corona, ca Posts: 198 Trader Rating: (2) Feedback Score: 2 reviews	Why do I keep overheating? even with tuarus fan i put a whole jug of 50/50 premixed antifreeze coolant in and filled the rest with water. have a tuarus fan on high speed at all times. but the damn thing still overheats, not so much on the freeway cause so much air. but when city driving and obviously parked, it over heats pretty fast. i know the guage isnt messed up cause when i pop the hood i can hear it boiling. the radiator seems to be ok, not too much rust. what could it be?

08-09-2006, 02:24 AM	#5
blu808 Post Whore! Join Date: Dec 2002 Location: Campbell, Ca Age: 42 Posts: 5,010 Trader Rating: (3) Feedback Score: 3 reviews	What most peeps dont realize is that when the rad cap is off, and you fill it up, it is just filling up the rad. One way to think of it is if your thermostat is a plug in you radiator. and when it finally opens after about 15 mins of idle, then it starts circulating coolant through the engine water jackets. I would recc that you start the motor completely cold. with the rad cap off, then keep feeding it water for 30 mins. after letting it run for 15 mins the thermo will open and suck up the water. Just keep feeding it, until there are no more air bubbles. Air is the main cause of overheating. Just think of air as your bin lauden. Get it all out. then before it starts gushing out cap it. make sure before this you have your coolant res filled. that way it wont suck up any bin lauden air. If that doesnt work. you may try changing your t stat. then your water pump. if that fails. do a leak down test and see if you have a blown cyl, or h gask. Poo FTW. __________________

08-09-2006, 02:26 AM	#7
blu808 Post Whore! Join Date: Dec 2002 Location: Campbell, Ca Age: 42 Posts: 5,010 Trader Rating: (3) Feedback Score: 3 reviews	no. your coolant temp sensor is in the water neck after the t stat. so if it failed it wouldnt even be close. KA, sr, rb, vg same stuff. __________________

08-09-2006, 01:43 AM	#2
Xren17 Zilvia Junkie Join Date: Jul 2003 Location: San Diego / Cerritos Posts: 341 Trader Rating: (4) Feedback Score: 4 reviews	Did you jack it up and bleed it through the bleeder valve? I had the same problem and it was fix after bleeding it.

08-09-2006, 01:57 AM	#3
driftkid316 Zilvia Member Join Date: Apr 2005 Location: corona, ca Posts: 198 Trader Rating: (2) Feedback Score: 2 reviews	im sorry, i dont know how to bleed it. how do i go about doing that? btw, i have a 90 s13 sohc

08-09-2006, 02:09 AM	#4
daryl337 Zilvia Junkie Join Date: Aug 2005 Location: Pac NW Age: 39 Posts: 589 Trader Rating: (1) Feedback Score: 1 reviews	There are many things that can cause an over-heating problem... but just by saying that your fan actually turns on eliminates about 50% of them. Try a new thermostat... 80% of the time that is the problem. If it isnt that, look for soft hoses, as well as flush your entire system a few times to make sure that there isnt rust in the BLOCK that is blocking anything. If it is not that, then look into the water pump cavitating. BTW.. bleeder valves USUALLY are on the intake manifold or the head (forgot where it is on the ka24e)... In any situation, it is going to be up high.

08-09-2006, 02:48 AM	#8
daryl337 Zilvia Junkie Join Date: Aug 2005 Location: Pac NW Age: 39 Posts: 589 Trader Rating: (1) Feedback Score: 1 reviews	Well, basically think of it like this. Your water pump is pumping away like the little pump it is... and from there... the water can go to two places... 1) it goes to your radiator where it is cooled... or two... it goes out your coolant bypass line and recirculates throughout the motor. When the thermostat is closed, no cool water comes from your radiator... and to prevent any pressure from building up in the radiator... the water is recirculated in the block. As the recirculated water heats up.. the thermostat opens up.. and lets the cooled water come in. Now... what does this mean for you? A sticky thermostat keeps your radiator from giving you cool water. =D But like I said.. also check for collapsing hoses... and do a good flush just to make sure you are getting proper flow.