strangest overheating issue

[oLemurs]

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]

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]

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]

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]

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]

any leaks or overflow overfilling?

[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

[KoukiMonsta]

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

Then I'll probably try and help.

[oLemurs]

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]

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]

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]

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

[oLemurs]

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]

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]

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]

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]

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]

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]

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]

Unless you're talkin 170 celsius...

[oLemurs]

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]

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]

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]

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]

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

[oLemurs]

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]

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]

Replace the water pump

[oLemurs]

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]

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

[R3b]

Chimming in because I have the same "issue" on my ka-t with koyo rad and mish fan shroud with 50/50 coolant mix.

Crusing from 2nd-3rd mixed driving on any day in florida from cool 64 to high 90s my temp is at 77-86c the highest (too lazy to convert since my gauge is my fan controller and got used to C)

But soon as I drive highway longer than 10mins over 10miles my temps rises like crazy. I have my fans kick on regularly at 66c but on highway my temps on longer drives 20mins + I get all the way up to 97-98c which is dumb hot for KA without AC I would think. I have AC and cruising its low 90s, I cant even put AC on highway because scared of overheating since its built block. I make 467 so I dont want to have do anything else on the car since its a builtproof daily...

Im thinking its my oem Tstat since a local by me similar specs had similar issue but went nismo Tstat and that helped a lot. He has a more serious setup and recently did an oil cooler which ill do eventually since I want to take longer trips in this soon.

Also big thing is im on e85 and obviously keeps the engine a bit cooler and big temp diffs when im pump.

Besides Tstat and going full distilled with water wetter idk what my highway temps are so high, maybe airflow because of AC parts or maybe need switch to mishi racefans?

[R3b]

double post..........

[Fade420sx]

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

I was just wondering where you got the hoses? I’m looking online to fine one specific hose that seems to have a bend right where it connects. got the feeling if I use s flexible hose it might pinch and the coolant won’t flow

[oLemurs]

I was just wondering where you got the hoses? I’m looking online to fine one specific hose that seems to have a bend right where it connects. got the feeling if I use s flexible hose it might pinch and the coolant won’t flow

which one man? heater core hoses need to be 3/4" in diameter and look for non kinking lines, all of the smaller coolant hoses are 5/16 and none of them will kink.

[Kingtal0n]

This is such an easy issue to diagnose.

The way to do this is use
random aluminum radiator
and either well known fans (Altima fans)
Or Mechanical OEM clutch fan and shroud

with good water pump and t-stat it will stay cold with proper engine cruise timing and a/f ratio whether its a stock engine or a 500 horsepower sr20det cruising on the highway makes little difference.

Many fans are no good for our cars. Many fans will block airflow more when they are ON while the car is cruising on the highway. Many OEM systems shut down fans for highway cruise. I think even the clutch fan has some kind of RPM bias that helps it slow down on the highway. Bottom line is if using oem fan or well known fan it won't matter though. What happens is people use junk fans that block airflow and don't work well.

I Put a random chinese $75 radiator with $69 Altima fans and it keeps a 5.3L V8 with turbo crossover tube 2" from the radiator 180*F all day

If you think the engine has some kind of gasket problem then pressure test the system. If its leaking into a cylinder then pressurize the radiator with the engine off and then check each cylinder hole for evidence of liquid water. Also perform compression and leakdown tests. Actually I would skip the leakdown. Just pressurize the radiator and see no water, test compression and done. change the fan. Use 100% distilled water if it doesn't freeze there.