overheating problem,,,searched.

ONLY for ADVANCED technical discussion about the 240sx!
EviL inside
Posts: 277
Joined: Fri Jul 21, 2006 4:39 pm
Car: 90 240sx

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completed DOHC swap on my S13. ran for a month.

water pump starts leaking from weep hole.replaced.

first time i drive it after new water pump, it starts to run hot,,,i park it and bleed it. twice.

replace thermostat and hoses (yes the little hole on the t-stat is straight up). bleed twice. antifreeze getting expensive.

starts to overheat and pops a hole in the upper tank near coolant inlet,,,no problem, i had a spare radiator from the swap. so i install it. and bleed.

starts to overheat and cracks radiator near coolant inlet. so i park it in my backyard and put a cover over it.

i find it hard to believe that both radiators are bad, the only thing that hasn't been replaced is the cap, which all the seals on it are good, and the spring pressure seems fine. while bleeding, the heater never gets hot, even though it will sit mid-way on the gauge for 20-30mins. as soon as i actually DRIVE it, it starts to heat up. i'm kinda lost here. any help?


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480sx
Posts: 4085
Joined: Sun Nov 12, 2006 5:27 pm
Car: 1996 Pearl White 240sx

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The Ka is a PITA sometimes to get all the air out of the system. Unless you put the thermostat in backwards, it sounds like you still have air in the system.

EviL inside
Posts: 277
Joined: Fri Jul 21, 2006 4:39 pm
Car: 90 240sx

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the thermostat is definitely in the right way, per FSM and the old, factory nissan thermostat.

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2056515
Posts: 99
Joined: Fri Mar 16, 2007 12:44 pm
Car: 240sx

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how exactly r u bleeding the system??

EviL inside
Posts: 277
Joined: Fri Jul 21, 2006 4:39 pm
Car: 90 240sx

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jacking the front up as high as i can get it, remove bleed screw (at coolant outlet on motor) slowly filling with 50/50 antifreeze mix until it starts coming out of the hole. start car, replace bleed screw. run for 20-30 minutes, revving every couple minutes, topping off as needed. heater is on full heat the whole time.

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2056515
Posts: 99
Joined: Fri Mar 16, 2007 12:44 pm
Car: 240sx

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weird....u r doing it perfect. might have something clogging the cooling system??...not too sure. after bleeding my 240...the needle on my temp gauge sits just above the middle. im not even sure if this is normal

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KFL
Posts: 656
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Car: S14
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Trying doing it old school I never had issue and just bleed my system a week ago after a tune-up. Leave the radiator cap off and start car bubbles will eventually rise towards the opening ~some spillage my occur but not a lot. I waited about 10mins..a with Heater on full. (Having front end slightly raised is good). When no more bubbles come up and it gurgles over the opening install cap and then check temp gauge.I have a koyo on my na ka and its reads just over the C, but thats expected running cooler. S13 rads are common to fail seen a few 3,4 in my years crack/fail plastic tanks+old age.

Chukidori
Posts: 828
Joined: Sat Apr 14, 2007 4:19 am

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Im having this same problem...

Changed thermostat Twice

New water pump

New hoses

If i let it idle with the A/C on it will over heat after about 2 minutes (after reaching normal operating temp)

But if it idles normally, its fine (or maybe i just havent let it idle long enough yet)

Im very confused, ive changed everything except the radiator.


EviL inside
Posts: 277
Joined: Fri Jul 21, 2006 4:39 pm
Car: 90 240sx

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so today i did a compression test to rule out a blown headgasket.

warmed it up first.

180psi exactly on all four cylinders.

i've tried using a "plastic weld" epoxy on the radiator that's in the car, but every time i get one leak sealed, another one comes to my attention.

will an S14 radiator fit in an S13? if so i might order an aluminum one on ebay,,,the only cheap KA24DE aluminum radiators i see are listed for S14's.

mwilloughby
Posts: 55
Joined: Tue Dec 26, 2006 1:28 pm

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dono if an s14 will fit into an s13, but heres a link to a good looking radiator w/ same specs as koyo

http://www.turbogoods.com/inde...ID=99

EviL inside
Posts: 277
Joined: Fri Jul 21, 2006 4:39 pm
Car: 90 240sx

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it looks like the lower posts are the same, i'd have to just relocate the top brackets,,,no problem. i can get the s14 aluminum radiator for just under $160.

if the only other choice was to pay nearly $300 for an aluminum one, i'd just stick with an OEM radiator for $100, or a junkyard replacement for $30. it's just a stock KA24DE.

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oneline180
Posts: 62
Joined: Fri Jul 09, 2004 4:30 am
Car: 93 RMS13, 2006 B15 Sentra, 1995 D21 Hardbody Pickup

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have you tried bypassing your heater core? it might be clogged, thats what my problem was. No problems since.

EviL inside
Posts: 277
Joined: Fri Jul 21, 2006 4:39 pm
Car: 90 240sx

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ordered new S14 KA24DE all aluminum radiator friday.

in the meantime, i picked this up today, for $300


Modified by EviL inside at 11:22 PM 6/7/2007

180fan
Posts: 7799
Joined: Sat Dec 14, 2002 12:16 pm
Car: 89 fastback

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lol Nice score. wait, how'd you pick that up for 300? gov't auction or something?

Chukidori
Posts: 828
Joined: Sat Apr 14, 2007 4:19 am

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Oh i hate you.

i used to own a 3000GT.

Wonderful fun little Luxury *** haulers they are.....not too high on the handling spectrum tho....

EviL inside
Posts: 277
Joined: Fri Jul 21, 2006 4:39 pm
Car: 90 240sx

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it's a katrina flood car. not sure how high the water got. not a new orleans car, the water went right back down. this is my 4th flood car project.

EviL inside
Posts: 277
Joined: Fri Jul 21, 2006 4:39 pm
Car: 90 240sx

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$160 aluminum S14 KA radiator arrived today.

fits s13 just fine. only had to relocate upper mounts.

EviL inside
Posts: 277
Joined: Fri Jul 21, 2006 4:39 pm
Car: 90 240sx

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UPDATE.

new radiator, new hoses, new water pump, new thermostat, 50/50 antifreeze mix, bled for 20 mins., heater works, compression test 180psi across the board.

still overheats under load. this thing is driving me nuts.

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aradapilot
Posts: 32
Joined: Sun Mar 04, 2007 10:32 am
Car: 1990 240sx se

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you got the cluch fan or electrics? if the fan clutch wears out you'd be amazed how fast they overheat. Check to make sure the fan stops spinning right after shutting off a hot engine, if it spins after the crankshaft stops when its hot that means it's worn. Something people rarely check - I went through this a couple years ago and it ended up being $40 for a new fan clutch and a quick install.

Chukidori
Posts: 828
Joined: Sat Apr 14, 2007 4:19 am

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Run it without the thermostat.

It fixed my problem. Check to make sure the radiator is actually flowing, open the cap and watch it a few minutes after it reaches operating temp, it should flow like a river ^_^.

Check ur hoses too, does your top one get hot but bottom one stays cold? i had this problem.

EviL inside
Posts: 277
Joined: Fri Jul 21, 2006 4:39 pm
Car: 90 240sx

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electric fan

the lower hose will get hot, but nowhere near what the upper hose is, naturally. it's not ice cold, and only gets warm after the car has had more than enough time to reach normal temp.

gonna change the water pump again, might be the impeller slipping on the shaft.

Chukidori
Posts: 828
Joined: Sat Apr 14, 2007 4:19 am

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Ah...my hose would stay ice cold...because there was no circulation.

slowfkncar
Posts: 22
Joined: Sun May 27, 2007 1:34 pm
Car: 93 fastback

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there is a coolant hose by the firewall just behind the intake manifold.

its supposed to be a "U" shaped hose.

check if its leaking or pinched

EviL inside
Posts: 277
Joined: Fri Jul 21, 2006 4:39 pm
Car: 90 240sx

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there's actually 2 hoses there, they are both for the heater core. it's not clogged. i pulled the hoses and stuck an air line in it. the heater core flows. the lines to the heater core are good. no other leaks. i have a warranty on the water pump, so if i'm gonna pull anything AGAIN,,,i'll just exchange the pump.

EviL inside
Posts: 277
Joined: Fri Jul 21, 2006 4:39 pm
Car: 90 240sx

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thought i'd post this for the benefit of later searches, if anyone else has this problem also.

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youngun21a
Posts: 293
Joined: Mon Mar 13, 2006 7:55 am
Car: 240sx 1993 Automatic

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Had the same proablem, spinner came out of new water pump after engine rebuild,put in a new one ,a month later, hose from the back of the block that goes to the heater core,had a leak on it,put in a new one ,it started to overheat, let it idel for 45min,it was fine, drove for half a block, overheat all the way to H!!, Let it cool, came back home, bottom hose cold, remove the Termastat, runs fine now, 3 week later it's started to overheat again only with ac on,turn the heater on back to normal,think is the clutch fan, or somthing is clog condenser fan,running out of ideas1!

1993, 240sx stock,engine rebuid everything new

EviL inside
Posts: 277
Joined: Fri Jul 21, 2006 4:39 pm
Car: 90 240sx

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when you completely remove the thermostat, you are shortening the time the water is in the radiator cooling down.

when the a/c is on, the condensor is adding heat to the air going to the radiator, and you are getting heat soak.

put a new thermostat back in, or at least a restrictor.

Chukidori
Posts: 828
Joined: Sat Apr 14, 2007 4:19 am

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I learned about an ingenious way of installing a thermostat from a nissan technician.

Mechanicaly force the valve open...and jam it with several aspirin to keep it pried open.

Then install and fill normally...this way its much easier to make sure theres no air trapped to lock the t-stat and cause problems. and the aspirin will naturally dissolve.

pr240sx
Posts: 1005
Joined: Mon Mar 03, 2003 7:43 am

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Chukidori wrote:I learned about an ingenious way of installing a thermostat from a nissan technician.

Mechanicaly force the valve open...and jam it with several aspirin to keep it pried open.

Then install and fill normally...this way its much easier to make sure theres no air trapped to lock the t-stat and cause problems. and the aspirin will naturally dissolve.
I also fill thru the upper rad hose until coolant flow out of the radiator. DOing that, you are forcing the air to escape to the radiator instead the engine.Removing yout thermostat will resolve a overheat condition but not an overheat situation. YOu will overheat at one point latter on.

Those are the new clutch water impellers!! they will turn when needed!!


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