strangest overheating issue - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

oLemurs · 07-07-2018, 08:17 PM

before you say use the search tool trust me ive searched every forum out there and cant find a similar issue.
so im having an issue where anytime i take it on the highway i start to overheat. i can drive it around town all day and no issues but as soon as i hit the highway it gets real hot.
i did notice due to a hot ambient temperature it would overheat more quickly (probably doesnt matter but just thought i should say it). if i pull over and wait like not even 5 minutes itll cool down all the way but as soon as i start driving it again.
i can drive it around town all day but i cant go a constant speed without stops. i also beat on the car a little and have no issues.
i check the coolant cap and so far no whiteness. i also bled the system very well for a solid 20-30 minutes with my coolant funnel.
i have a BRAND new ISR Radiator ISR Fan shroud with fans. and before you ask no they are not wired backwards, i have them behind the radiator pulling air.
so far i replaced the thermostat, and looped the heater core line because i thought the kink caused issues. heres some pictures that might help you help me diagnose the issue. water pump doesnt leak or make strange noises but that is on the list of things to be replaced, along with a coolant flush (even though the coolant is not even a year old and has barely any use on it.)
https://imgur.com/gallery/hxPweOo

unicoder · 07-08-2018, 08:55 AM

If you are going to go through the trouble of telling us not to telll you to search. Do us a favor and list all the important things and their results too.

1. Have you confirmed your fans are working correctly?
2. Have you REALLY bled your cooling system to make sure there is no air? For some people, they have a hard time getting the last bit of air out on these cars.
3. Did you install the thermostat correctly? They are directional and you need the jiggle valve positioned at 12 o'clock.
4. When the car warms up, is the upper radiator hose cool or warm? is the bottom hose cool or warm?
5. Have you replaced the radiator cap?
6. Can you see the coolant flowing when you let your car warm up from idle and remove the radiator cap? (it wont move while cold), to confirm the thermostat is opening?

Use all the questions normally asked in the other threads you searched, to give us info in this thread to help out

oLemurs · 07-08-2018, 09:04 AM

Quote:

Originally Posted by unicoder

If you are going to go through the trouble of telling us not to telll you to search. Do us a favor and list all the important things and their results too.

1. Have you confirmed your fans are working correctly?
2. Have you REALLY bled your cooling system to make sure there is no air? For some people, they have a hard time getting the last bit of air out on these cars.
3. Did you install the thermostat correctly? They are directional and you need the jiggle valve positioned at 12 o'clock.
4. When the car warms up, is the upper radiator hose cool or warm? is the bottom hose cool or warm?
5. Have you replaced the radiator cap?
6. Can you see the coolant flowing when you let your car warm up from idle and remove the radiator cap? (it wont move while cold), to confirm the thermostat is opening?

Use all the questions normally asked in the other threads you searched, to give us info in this thread to help out

yea sorry,
1. they work correctly i shut them off while overheating and it spiked bad. oh yea forgot to mention i have them wired up to a switch on individual relays.
2. ill try to re bleed it and jack up the front end again
3. jiggle valve is directly at the top
4. both of the hoses are very hot
5. i have not but this is the one that came with the radiator. its 1.1 bar
6. i know the thermostat is opening because the same thing happened with my last one and i put the old one in boiling water.

S13project · 07-08-2018, 01:56 PM

Is the cap sealing properly with the radiator? Had same thing happen on another car, but with OEM radiator. The ledge the cap sits on was slightly eroded, so when the pressure would rise up it wouldn't hold and thus not cool properly. Never leaked either which puzzled the crap out of me.

oLemurs · 07-08-2018, 07:41 PM

Quote:

Originally Posted by S13project

Is the cap sealing properly with the radiator? Had same thing happen on another car, but with OEM radiator. The ledge the cap sits on was slightly eroded, so when the pressure would rise up it wouldn't hold and thus not cool properly. Never leaked either which puzzled the crap out of me.

tbh it looks good, radiator and cap are both new and i just pressure tested it. at 1.1 bar itll hold for a pretty long time but slowly let out just like the whole system

rawgarage · 07-09-2018, 04:01 AM

any leaks or overflow overfilling?

KAT-PWR · 07-09-2018, 08:04 AM

I had something similar, it was a pin hole in a hose under intake manifold. Finally found it. Would only have enough pressure to leak when hot

KoukiMonsta · 07-09-2018, 08:31 AM

utilize the return key once in a while, so I can actually read the post.

Then I'll probably try and help.

oLemurs · 07-09-2018, 10:33 AM

Quote:

Originally Posted by KoukiMonsta

utilize the return key once in a while, so I can actually read the post.

Then I'll probably try and help.

fixed the spacing

oLemurs · 07-09-2018, 10:35 AM

Quote:

Originally Posted by rawgarage

any leaks or overflow overfilling?

no overflow overfilling BUT when i pressurized the system the pressure would slowly let out, i mean real slow but i think im going to pull the intake manifold and delete all the BS lines under there

oLemurs · 07-09-2018, 10:35 AM

Quote:

Originally Posted by KAT-PWR

I had something similar, it was a pin hole in a hose under intake manifold. Finally found it. Would only have enough pressure to leak when hot

good idea, im going to be re doing all the hoses under the intake manifold since some of them are still the original ones.

KoukiMonsta · 07-09-2018, 10:55 AM

you sure water pump is good? I have seen them where the fins are literally gone from years of corrosion.

oLemurs · 07-09-2018, 11:46 AM

Quote:

Originally Posted by KoukiMonsta

you sure water pump is good? I have seen them where the fins are literally gone from years of corrosion.

see thats what i was thinking, but it didnt really make sense to me until you explained it this way

KoukiMonsta · 07-09-2018, 12:59 PM

Quote:

Originally Posted by oLemurs

see thats what i was thinking, but it didnt really make sense to me until you explained it this way

I used to work in one of the big name auto parts stores, I've seen some stuff that is just 'how the fuck did you do this?'

But I'll never forget the waterpump this guy brought in. The fins/blades were paper thin, like tin foil. I mean, was the guy running salt water in the fucking radiator?

I cannot view imgur so idk what that pic is.

what motor you got? SR?

my initial thought, and why I asked if you have actually looked at the pump, is that you aren't flowing enough water.

At higher RPM you generate more heat, and water pump turns faster to compensate. But when you are at higher rpm the engine cant cool quick enough. this makes me think water flow.

Have you flushed the system? old hoses, could have blockage? Fresh new coolant to go with with ur new rad?

KiDyNomiTe · 07-09-2018, 01:44 PM

Define overheat? What temps? Or is this just the stock gauge? How old is the temp sensor?

It kind of sounds like an airflow problem. If I understand, you have beat on it at low speeds and it was fine. As in you've been higher in the RPMs at low speeds, but once you get up to 65+ it starts overheating?

Is there any blockage in front of the radiator, or do you still have an AC condenser.

oLemurs · 07-09-2018, 07:59 PM

Quote:

Originally Posted by KiDyNomiTe

Define overheat? What temps? Or is this just the stock gauge? How old is the temp sensor?

It kind of sounds like an airflow problem. If I understand, you have beat on it at low speeds and it was fine. As in you've been higher in the RPMs at low speeds, but once you get up to 65+ it starts overheating?

Is there any blockage in front of the radiator, or do you still have an AC condenser.

yea about at 60 itll overheat but the faster i go the quicker it overheats. i did notice after it was a little over 170 and i take it off the road going about 35 itll still overheat just slower. i have no AC condensor but i do have a huge intercooler up front wich is very clean.

oLemurs · 07-09-2018, 08:02 PM

Quote:

Originally Posted by KoukiMonsta

I used to work in one of the big name auto parts stores, I've seen some stuff that is just 'how the fuck did you do this?'

But I'll never forget the waterpump this guy brought in. The fins/blades were paper thin, like tin foil. I mean, was the guy running salt water in the fucking radiator?

I cannot view imgur so idk what that pic is.

what motor you got? SR?

my initial thought, and why I asked if you have actually looked at the pump, is that you aren't flowing enough water.

At higher RPM you generate more heat, and water pump turns faster to compensate. But when you are at higher rpm the engine cant cool quick enough. this makes me think water flow.

Have you flushed the system? old hoses, could have blockage? Fresh new coolant to go with with ur new rad?

yea SR20 and i have not looked up the pump internally. and what you said about being low rpm with high heats is EXACTLy what i was thinking. i still have some really old hoses which will be looped when i do the water pump.

KoukiMonsta · 07-10-2018, 06:54 AM

Quote:

Originally Posted by oLemurs

a little over 170

Hold the phone.

170 is COLD.

'Define overheat? What temps? Or is this just the stock gauge? How old is the temp sensor? '

KiDyNomiTe · 07-10-2018, 07:28 AM

Quote:

Originally Posted by KoukiMonsta

Hold the phone.

170 is COLD.

'Define overheat? What temps? Or is this just the stock gauge? How old is the temp sensor? '

Ya what? For summer time, especially considering its been the hottest all year that temp is cold. Overheating is around 230.

tuzzio · 07-10-2018, 08:06 AM

Unless you're talkin 170 celsius...

oLemurs · 07-10-2018, 11:33 AM

Quote:

Originally Posted by KiDyNomiTe

Ya what? For summer time, especially considering its been the hottest all year that temp is cold. Overheating is around 230.

no no i was saying 170 as like when even if it starts overheating at all, it gets up to 200 if i dont let it cool down

KoukiMonsta · 07-10-2018, 01:26 PM

some background knowledge for ya, you can find actual science for this shit...here's the concept.

water boils at 212 degrees freedom
water under pressure, such as in a cooling system, boils at some temp above 212
coolant boils at some temp higher than water

therefore - coolant under pressure boils at a temp higher than regular ass water.

under 200 is too cold. 200 is fine. 220 is getting hot. 230 is too hot.

beems240sx · 07-10-2018, 02:45 PM

Shit my 1J spiked at 250 at the track last hot lap event. My last SR never let it past 230 in fear of warping the head. where do you have your aftermarket temp gauge reading from? is the temp sensor properly grounded with NO teflon?

KiDyNomiTe · 07-11-2018, 08:13 AM

Quote:

Originally Posted by oLemurs

no no i was saying 170 as like when even if it starts overheating at all, it gets up to 200 if i dont let it cool down

See how hot it gets, if you hit 230 slow down, and you have a real problem, if it sits around 200 at 70MPH you should be fine.

tuzzio · 07-11-2018, 10:09 AM

If it stays at 200 when its 90* outside...you're doing just fine

oLemurs · 07-12-2018, 05:46 AM

Quote:

Originally Posted by KiDyNomiTe

See how hot it gets, if you hit 230 slow down, and you have a real problem, if it sits around 200 at 70MPH you should be fine.

well it WILL keep going up just very slowly

oLemurs · 07-27-2018, 01:36 PM

ok guys i just installed a new coolant temp sensor. on the short drives it was getting to be about 210 before i pulled over yet the stock temp sensor was just in the middle i really dont know what to believe now also when i went up a giant hill it was hitting almost 220 which and the factory sensor was still sitting in the middle. i really dont know what to believe at this point but if my glow shift gauge is correct than i definately went over 230 degrees and at that point is it even worth rebuilding a stock sr when i can just get a new one for 2600? im afraid the head might have warped. i went through all of the coolant lines and replaced them along with an s15 water neck to run stainless turbo coolant lines.

OutlawLui · 07-27-2018, 02:40 PM

Replace the water pump

oLemurs · 07-27-2018, 04:42 PM

Quote:

Originally Posted by OutlawLui

Replace the water pump

i bought a new one and when i took off the old one it looked brand new so i just re gasketed it

oLemurs · 07-27-2018, 05:30 PM

alright so heres what im thinking, its either a slightly bad headgasket (or warped head), the turbo is burning some of the coolant (would make sense because last owner "rebuilt" it and he wasnt the sharpest tool in the shed) OR the FMIC is blocking alot of the air flow to the radiator. what im going to do is take out the SR and sell it. jk but im going to check for carbon in the coolant, if not that then get a legit koyorad instead of this isr bullshit and if im still having issues im going to jump off a cliff

07-07-2018, 08:17 PM	#1
oLemurs Zilvia Member Join Date: Aug 2017 Location: MO Posts: 196 Trader Rating: (0) Feedback Score: 0 reviews	strangest overheating issue before you say use the search tool trust me ive searched every forum out there and cant find a similar issue. so im having an issue where anytime i take it on the highway i start to overheat. i can drive it around town all day and no issues but as soon as i hit the highway it gets real hot. i did notice due to a hot ambient temperature it would overheat more quickly (probably doesnt matter but just thought i should say it). if i pull over and wait like not even 5 minutes itll cool down all the way but as soon as i start driving it again. i can drive it around town all day but i cant go a constant speed without stops. i also beat on the car a little and have no issues. i check the coolant cap and so far no whiteness. i also bled the system very well for a solid 20-30 minutes with my coolant funnel. i have a BRAND new ISR Radiator ISR Fan shroud with fans. and before you ask no they are not wired backwards, i have them behind the radiator pulling air. so far i replaced the thermostat, and looped the heater core line because i thought the kink caused issues. heres some pictures that might help you help me diagnose the issue. water pump doesnt leak or make strange noises but that is on the list of things to be replaced, along with a coolant flush (even though the coolant is not even a year old and has barely any use on it.) https://imgur.com/gallery/hxPweOo Last edited by oLemurs; 07-09-2018 at 10:33 AM..

07-08-2018, 08:55 AM	#2
unicoder Zilvia Member Join Date: Apr 2017 Location: Alabama Posts: 160 Trader Rating: (2) Feedback Score: 2 reviews	If you are going to go through the trouble of telling us not to telll you to search. Do us a favor and list all the important things and their results too. 1. Have you confirmed your fans are working correctly? 2. Have you REALLY bled your cooling system to make sure there is no air? For some people, they have a hard time getting the last bit of air out on these cars. 3. Did you install the thermostat correctly? They are directional and you need the jiggle valve positioned at 12 o'clock. 4. When the car warms up, is the upper radiator hose cool or warm? is the bottom hose cool or warm? 5. Have you replaced the radiator cap? 6. Can you see the coolant flowing when you let your car warm up from idle and remove the radiator cap? (it wont move while cold), to confirm the thermostat is opening? Use all the questions normally asked in the other threads you searched, to give us info in this thread to help out __________________ 5.3 V8 Swap w/ Nitrous

07-08-2018, 01:56 PM	#4
S13project Zilvia Junkie Join Date: Mar 2006 Location: dirtysouth Posts: 530 Trader Rating: (7) Feedback Score: 7 reviews	Is the cap sealing properly with the radiator? Had same thing happen on another car, but with OEM radiator. The ledge the cap sits on was slightly eroded, so when the pressure would rise up it wouldn't hold and thus not cool properly. Never leaked either which puzzled the crap out of me. __________________

07-09-2018, 08:04 AM	#7
KAT-PWR Nissanaholic! Join Date: Dec 2011 Location: US Posts: 2,040 Trader Rating: (11) Rides Gallery: KAT-PWR Feedback Score: 11 reviews	I had something similar, it was a pin hole in a hose under intake manifold. Finally found it. Would only have enough pressure to leak when hot __________________ MRP Manufacturing

07-09-2018, 08:31 AM	#8
KoukiMonsta Nissanaholic! Join Date: Mar 2009 Location: NC Posts: 1,969 Trader Rating: (23) Feedback Score: 23 reviews	utilize the return key once in a while, so I can actually read the post. Then I'll probably try and help. __________________ @UpshiftEngineering

07-09-2018, 04:01 AM	#6
rawgarage Banned from the Marketplace Join Date: Oct 2007 Location: h o u s t o n Age: 35 Posts: 5,986 Trader Rating: (75) Feedback Score: 75 reviews	any leaks or overflow overfilling?

07-09-2018, 10:55 AM	#12
KoukiMonsta Nissanaholic! Join Date: Mar 2009 Location: NC Posts: 1,969 Trader Rating: (23) Feedback Score: 23 reviews	you sure water pump is good? I have seen them where the fins are literally gone from years of corrosion. __________________ @UpshiftEngineering

07-09-2018, 01:44 PM	#15
KiDyNomiTe Post Whore! Join Date: Mar 2002 Location: Chicago Age: 37 Posts: 6,296 Trader Rating: (0) Rides Gallery: KiDyNomiTe Feedback Score: 0 reviews	Define overheat? What temps? Or is this just the stock gauge? How old is the temp sensor? It kind of sounds like an airflow problem. If I understand, you have beat on it at low speeds and it was fine. As in you've been higher in the RPMs at low speeds, but once you get up to 65+ it starts overheating? Is there any blockage in front of the radiator, or do you still have an AC condenser. __________________ PROCEED Grip Gambler

07-10-2018, 08:06 AM	#20
tuzzio Post Whore! Join Date: Oct 2013 Location: Western Mass. Posts: 2,604 Trader Rating: (3) Feedback Score: 3 reviews	Unless you're talkin 170 celsius...

07-10-2018, 01:26 PM	#22
KoukiMonsta Nissanaholic! Join Date: Mar 2009 Location: NC Posts: 1,969 Trader Rating: (23) Feedback Score: 23 reviews	some background knowledge for ya, you can find actual science for this shit...here's the concept. water boils at 212 degrees freedom water under pressure, such as in a cooling system, boils at some temp above 212 coolant boils at some temp higher than water therefore - coolant under pressure boils at a temp higher than regular ass water. under 200 is too cold. 200 is fine. 220 is getting hot. 230 is too hot. __________________ @UpshiftEngineering

07-10-2018, 02:45 PM	#23
beems240sx Zilvia FREAK! Join Date: Jun 2008 Location: Phoenix Posts: 1,135 Trader Rating: (10) Feedback Score: 10 reviews	Shit my 1J spiked at 250 at the track last hot lap event. My last SR never let it past 230 in fear of warping the head. where do you have your aftermarket temp gauge reading from? is the temp sensor properly grounded with NO teflon? __________________

07-11-2018, 10:09 AM	#25
tuzzio Post Whore! Join Date: Oct 2013 Location: Western Mass. Posts: 2,604 Trader Rating: (3) Feedback Score: 3 reviews	If it stays at 200 when its 90* outside...you're doing just fine

07-27-2018, 01:36 PM	#27
oLemurs Zilvia Member Join Date: Aug 2017 Location: MO Posts: 196 Trader Rating: (0) Feedback Score: 0 reviews	ok guys i just installed a new coolant temp sensor. on the short drives it was getting to be about 210 before i pulled over yet the stock temp sensor was just in the middle i really dont know what to believe now also when i went up a giant hill it was hitting almost 220 which and the factory sensor was still sitting in the middle. i really dont know what to believe at this point but if my glow shift gauge is correct than i definately went over 230 degrees and at that point is it even worth rebuilding a stock sr when i can just get a new one for 2600? im afraid the head might have warped. i went through all of the coolant lines and replaced them along with an s15 water neck to run stainless turbo coolant lines.

07-27-2018, 02:40 PM	#28
OutlawLui Zilvia FREAK! Join Date: Apr 2011 Location: Anaheim CA Age: 37 Posts: 1,491 Trader Rating: (19) Feedback Score: 19 reviews	Replace the water pump __________________ .

07-27-2018, 05:30 PM	#30
oLemurs Zilvia Member Join Date: Aug 2017 Location: MO Posts: 196 Trader Rating: (0) Feedback Score: 0 reviews	alright so heres what im thinking, its either a slightly bad headgasket (or warped head), the turbo is burning some of the coolant (would make sense because last owner "rebuilt" it and he wasnt the sharpest tool in the shed) OR the FMIC is blocking alot of the air flow to the radiator. what im going to do is take out the SR and sell it. jk but im going to check for carbon in the coolant, if not that then get a legit koyorad instead of this isr bullshit and if im still having issues im going to jump off a cliff