weird overheating problems

[midnight_rex]

well this is happening in a s14 with a redtop SR.

i was using some renky-dink cooling fan for a good while. i used to have a serious overheating problem when i had a oem thermostat in the motor. i took it out and ran without one for a good while. the motor stayed at cool temperatures as i was surprised at this.

now that its getting hotter down here in tx ive noticed that my car overheats while im on freeway drives. i invested in a nismo thermostat and installed it. i bled the system for ait pockets for a good while. i then test the car out to see how it performs with the new thermostat. At idle it tends to heat up quick at start up which i thought was weird. so i let it get at warm operating temps. after 15 mins of letting it sit, temp started to climb slowly. i then drive the car and it cooled down due to increased air flow. now that i have my AC installed, i think the condenser decreases airflow to my radiator. on top of that i have my intercooler in the way also. my car starts to overheat after 10 mins of highway driving.

i then invest in 2 universal fans from the auto parts store. one is a 14'' that pushes 1200 CFM and the other is a 12'' that pushes 800 CFM. i mount them both used as pullers. i flush the radiator out and bleed the system again. testing the car out, again the car warms up quit fast and i let it warm up. i drive around for a good while and the temps seem to stay cooler. when im sitting still temps dont seem to climb at all. when i start driving temps drop back down but climb a lil after 10 mins of driving and never get too hot.

i thought it was weird how the car warms up quit fast so i thought that i needed to change out the coolant temp sensor. i dont know if the previoud owner swapped it out for a KA one or not so i decided to swap it out anyway. now that i have the new temp sensor in, the gauge seems to be a lil more accurate.

my car still tends to reach higher temperatures for some reason. what could this be? what else more can i do to keep the system on colder temps? i bled the system as good as i could but one thing i want to ask amd make sure, when no more bubbles are running out of the radiator from the cap that means there is no more air in the system right?

ps. - what are the differences between the KA temp sensor and the SR? is there a way to determine weather i had a SR or KA by looking at it?

[mad-ass]

KA and SR Temp sensors are same. I'd suggest getting an aftermarket water temp sensor as it's more accurate and reads way more wide range of temp then the OEM gauge does. and by the time it gets hot on your OEM temp gauge, it's already too late. Your temp water temp should be around 180F as a normal temp while driving around in city/HW. when I'm drifting at the track, the temp shoots up to about 200~210F, and after i finish up, I let it cool down with the e-Fan or driving the car around at low RPM at about 30mph or so.

How are you bleeding your system? are you using the bleeder screw at all? you should have the front of the car jacked up as high as possible when you are doing a coolant flush. or park in a steep hill.

I've had that mystrious over heating problem before on my KA, I replaced my thermostat/water pump/radiator cap/cooling panel/raised hood and problem went away for ever.

also, how does your belts look? if they are old and riggidy/cracking, you should change them out as old belts just put more stress on the pullies/motor then it should. and having a proper tension on the belts is crucial to a good operation.[proper tension on the belts you ask? when it's tight, it should have about 1/8th of inch of play in tension when you press it down with your fingers]

seems like you aren't doing a proper bleeding on the cooling system. at cool temp, open the radiator cap and the bleeder screw[located on the intake manifold on #1 intake chamber], and fill the radiator with coolant/distilled water untill you see a steady stream of coolant/water coming out.[it would be good to have two people doing this actually]. have your friend/dad/girlfriend pour in the coolant/water into the radiator while you re-bolt the bleeder screw. and after that...

turn the car on, and keep filling as needed. you may have to repeat this process couple of times to ensure of good bled cooling system.


and if it still happends and you don't have any coolant system leak that's visible? then you have bigger problems[I.E. Blown head gasket]

Hope my long essay helps.

[midnight_rex]

well a blown headgasket would be noticeable through exhaust or low coolant. i never have low coolant problems and there is no smoke what so ever coming out of the exhaust.

ill try that bleeding process tomorrow. ill update tomorrow on how the car reacts during the day when its hotter outside. thanks for the info mad-ass. no i didnt use the bleeder screw. my friend helped me bleed the system. he works at toyota so i was showing me how to bleed it.

ive read about jacking the car up but i never tried it. i also read that the SR and KA sensors are not the same.

[shmit001]

SR and KA sensors are the same. Same part#. I broke my SR one when I was taking it out, so I swap in the KA one. When I put my KA back in, I took the sensor out of the SR and put it back in the KA.

[midnight_rex]

well at night the car stays cool and when im driving on hwy or freeway during the day the temp shoots up close to hot but not all the way hot. i dont get it. there shouldnt be so many things to change out to keep the motor from overheating. maybe its cause im using straight water and no 50/50 antifreeze? im gonna get a temp gauge and see what it will tell me. driving down the freeway should be cooling the motor down with more air flowing thru and not overheating. the stock gauge has to be wrong. also, when i start the car and let it warm up from 8 hours of sitting the temp gauge tells me its warmed up from letting it idle for 1 minute. the temp gauge climps to normal operating temps from 1 minute of warming up.

[mad-ass]

oh shit..straight water? you need to run water wetter from redline if you are planning on running straight water man! keep your system lubricated so they don't over rust up with straight water.

[midnight_rex]

*******UPDATE*******
today while i was driving to go to work temperatures seemed to be ok driving on small roads at cruising speeds. after about 10 mins of driving thru small streets to work i get on the freeway. i noticed the temp started to climb while getting on the freeway and kept climbing as i was accelerating. when i got to work i popped the hood to check the level in the radiator and my resarvoir. low and behold! all the water that was in the resarvoir was gone and the radiator seemed to be a lil low on coolant.

well tonight i drained the water out of my radiator and planned to use 50/50 with water wetter. mad-ass i couldnt locate the bleeder screw for the coolant on the #1 intake runner. i did see one on the water neck outlet near the turbo manifold.

i drained all water out of the radiator and filled it up with coolant then water. i had the car running and kept filling the radiator with water and was squeezing the hoses to get any air out. while doing this i had the car jacked up in the air from the front. i also had the bleeder screw open until a smooth stream of water was coming out. i kept the car running for a good hour with the heater on and the cap off the radiator.

the temperature gauge needle was in the middle the whole time. it never moved any hotter or colder while i was bleeding the coolant system.

i decided to take the car for a test drive. going 30 mph down a small street for 3 miles, the car temperature seemed to raise at 2k rpm. i was just cruising first. so i decide to speed up to see if it will raise. as im speeding up the temperature drops immediately to cool temps.

i got on to a hwy going 50 mph at 3.5k rpm and the temperature gauge was giving cool readings. when i was stopped at a light the temp would raise just a small bit. while driving off from the light and rmp starts to rise higher in each gear the temperature drops instantly to normal temperature.

i reach freeway road and decide to drive around houston, tx for 15 miles in 5th gear at 4k rmp cruising. the temp gauge needle stayed right in the middle. i picked up speed and rmp raises higher while the temp goes higher and higher. it almost reached the "H" line so i slowed down and was cruising at 3k rmp. temps droped down to normal cool temps.

back on a major street, i cruise back home. the temperature kept cool all the way home. what could have caused the system to suck all the water out of the resarvoir? i looked for leaks all over the motor and see nothing!! no smoke coming out of the exhaust and no milky color to the oil. this is really getting on my nerves that the temp is reading wierd in different daily driving conditions. could my gauge be reading wrong? im going to get a aftermarket temp gauge soon so that is out of the question. the only thing left to replace is my water pump. WHAT COULD IT BE!!!!!!!!!!????

[johngriff]

The stock "gauge" is a 3 position thermoswitch. Cold, warm, fucked (hot).

Throw it away.

Sounds to me like a mechanical problem. I would do a leak down, and pressure test the coolant system.

[midnight_rex]

The stock "gauge" is a 3 position thermoswitch. Cold, warm, fucked (hot).

Throw it away.

Sounds to me like a mechanical problem. I would do a leak down, and pressure test the coolant system.
so ur saying to get a aftermarket temp gauge. will do!

mechanical problem as in water pump? and how would i do a leak down and pressure test for the coolant system?

[mad-ass]

yeah, deff. install after market gauge. I have Prosports gauge in my S14 and Autometer in my S13. they both work great, only difference is that Prosports are LED lit with red needle and have reading from 140F~240F in 3/4th of a circie, and autometer reads from 140F~220F with old school red metal needle. and just back lit. But reguardless, they both work like they are suposed to and both are cheap! you can get either one for under $50 shipped.

and it really sounds like you have a coolant leak somewhere.

Oh, one more thing, when you installed the thermostat, did you install the jiggle valve on top Top Dead Center or else where? because if you don't have the jiggle valve on the top[which is designed for the air bubbles to pass through allowing a full air-proff cooling system], your engine will most likely over heat. or it could just be that you have a leak.

good luck!

[midnight_rex]

yeah, deff. install after market gauge. I have Prosports gauge in my S14 and Autometer in my S13. they both work great, only difference is that Prosports are LED lit with red needle and have reading from 140F~240F in 3/4th of a circie, and autometer reads from 140F~220F with old school red metal needle. and just back lit. But reguardless, they both work like they are suposed to and both are cheap! you can get either one for under $50 shipped.

and it really sounds like you have a coolant leak somewhere.

Oh, one more thing, when you installed the thermostat, did you install the jiggle valve on top Top Dead Center or else where? because if you don't have the jiggle valve on the top[which is designed for the air bubbles to pass through allowing a full air-proff cooling system], your engine will most likely over heat. or it could just be that you have a leak.

good luck!
i dont remember if i installed it on top dead center. i hope that is not the case.

[Headsick]

My s13 did the same thing right before the radiator cracked, and again after I replaced it. So it could be a possible small leak, as mentioned, or there could still be an air bubble in the system.

[godzilla_753]

i would def take a look at the water pump, having very similar problems myself right now, im changing the water pump, ill let you know if it fixed it.

[midnight_rex]

i would def take a look at the water pump, having very similar problems myself right now, im changing the water pump, ill let you know if it fixed it.
yea please let me know how it goes. i wont be able to get a new water pump until next week.

[midnight_rex]

well i just found out tonight that my water pump is leaking. i was driving on the freeway for a while and then i was stopped at a light. i smelled coolant coming from outside so i pulled over and popped the hood open. i look down at the water pump and see coolant seeping from the water pump onto the block.

i guess when i had straight water in the system, when it seeped out onto the block the water evaporated immediately. thats why i didnt notice it before. im going to replace with a s14 SR water pump rather than a s13 cause i read that the s14 flows better and acts as a upgrade for the s13 SR. only one mounting hole doesnt bolt up. but people say it still seals and works perfect. has anyone else done this?

does the seal go out and cause a leak? an does it cause the pump to have a poor water flow? im trying to understand whats going on with the pump. can someone explain?

[fliprayzin240sx]

To alleviate the confusion in this thread. Gauge water temp sensor ARE NOT ALL THE SAME. It can cross reference between KA and SRs but the catch is you have to use the water temp sensor for the chassis, not the engine. So if you have an S13 SR into an S14 chassis, you'd need an S14 sensor either off your stock S14 KA or an S14 SR.

[midnight_rex]

yea i already have a new KA temp sesnsor in.

can someone comfirm the s14 SR water pump on a s13 redtop?

what about the water pump failure? can someone explain why it fails to flow poorly when the seal is gone? mine hasnt siezed up its just leaking.

[Banegraphix]

The S14 water pump can be used on a redtop just one of the lower bolt holes aren't used on the pump