SR, Weird overheating problem...help!?

[MandTPhotography]

Alrighty, first off, the motor is an S13 SR, stock T25, injectors, etc;...

I've got a Koyo Radiator, and two e-fans.


It's about 50-60 degrees during the day, and my car won't stop overheating. It'll be fine driving around highway speed or while it's moving, but when it's idling, the temp needle just keeps rising.

First off, we wired up another fan (Used to be 1.), flushed the radiator, and changed the thermostat, but the problem still persists.

I have no idea whether it's the gauge itself, the waterpump or maybe a leak in the headgasket.

There is a small coolant disappearing act, but I'm not leaking it, I suppose just burning it off. It's a small leak though, so I'm not exactly sure what's up.


Anyone have any idea? I have a new waterpump and we'll be replacing that tomorrow to see if that's what the problem is.



tl;dr - Car overheats after driving, while idling. Flushed coolant, replaced thermostat, wired up an extra e-fan, to no avail. Need ideas.

[jackal264]

coolant disapearing + no leak = hg = overheating

[fliprayzin240sx]

If you have a leak, you could be letting air into the system. Air does not cool the engine.

[sidetrack9]

^ could be either one...also if your heater core is bad or clogged it will also cause your car to over heat.The only way to fix it is to fix the heater box or to recirculate the heater hose to the engine only...but u should check to c if u have a blown hg first if the water pump thing does not work...gl

[MandTPhotography]

This sounds ridiculous, but while in a parking deck today, I noticed my e-fans were cutting off randomly. I didn't realize my e-fans were cutting off because I can't hear them while I'm driving/idling.

My fans only cut off while the car is driving, not while idling. Maybe the wires are rubbing something and shorting, who knows. I'll check it out in a few, I'm off to put new tires on the car. =]

[MandTPhotography]

So of course it turns out to be something ridiculous...


The switch for my e-fans was shorting out somehow, and the wires were melted together and barely making contact. Fixed that, but now the wires are coming loose so I just have to re-wrap them or rewire where they are or something.

[MandTPhotography]

^ That was definitely not the problem.

Car was still overheating, so we took the thermostat out again to see if the car still overheated. It doesn't...hooray.

[Ceepo]

yeah not good to run your car without a thermostat...

[wangan_cruiser]

pressurize your coolant. see if theres any minor leak. when you leave and drive off do you see any drip leaks?

my sr currently leaks overnights because the hose i found seals up when its warm but when its cold it is leaking. but i dont overheat when i drive it.

[clark]

if you overheated that many times, you probably warped your head...it's aluminum...

nowhere did you mention in your post that you properly bled your system of air...have you done this?

do you have a shroud? also, do you have a wiring diagram of your fan/switch/relay wiring?

[wangan_cruiser]

or you can do a leakdown test.

start it up let it warm up
turn off the engine let it sit and cools down
then take off sparkplugs
then if you have a compressor pressurize the combustion chamber with air
then open up oil filer cap and radiator cap.

listen to any hiss coming from

intake - intake valves not sitting properly or leaking from gaskets
exhaust - exhaust valves not sitting properly or leaking from any places
oil filler cap - cracked head?
bubbles in radiator - headgasket is slowly deteriorating
hissing from dipstick? - rings are on their way out.

[steve shadows]

everyone on this forum should be running a swirl pot by now

[MandTPhotography]

pressurize your coolant. see if theres any minor leak. when you leave and drive off do you see any drip leaks?

my sr currently leaks overnights because the hose i found seals up when its warm but when its cold it is leaking. but i dont overheat when i drive it.

My car doesn't leak at all, unfortunately.

if you overheated that many times, you probably warped your head...it's aluminum...

nowhere did you mention in your post that you properly bled your system of air...have you done this?

do you have a shroud? also, do you have a wiring diagram of your fan/switch/relay wiring?

It hasn't like..overheated to the point of cutting off or anything, just ran hot. Not all the way to the H either, just way hotter than I'd like.

Everytime we lost any coolant, we got out all the air bubbles in the system and let it recirculate and whatnot.
or you can do a leakdown test.

start it up let it warm up
turn off the engine let it sit and cools down
then take off sparkplugs
then if you have a compressor pressurize the combustion chamber with air
then open up oil filer cap and radiator cap.

listen to any hiss coming from

intake - intake valves not sitting properly or leaking from gaskets
exhaust - exhaust valves not sitting properly or leaking from any places
oil filler cap - cracked head?
bubbles in radiator - headgasket is slowly deteriorating
hissing from dipstick? - rings are on their way out.


Very useful...Will definitely do this shortly in the future. Bought a DD this week so I'll have time to fix the 240.

Thanks everyone!
:hsdance: