How to bleed coolant system?

[onecrazyfoo4u]

I've been searching and can't find anything related to the sr20 motors. Anyways, I've got a new thermostat and both new coolant temp sensors on the way and I want to install them all the same time I drain and bleed the system. I'm used to just opening the cap at the bottom of the radiator and draining, then refilling. Didn't know you were supposed to bleed the system.

So, how exactly do you do this? Is there a special way to refill with coolant and bleed the air out? Also, is the thermostat located where the bottom radiator hose goes or where the top one goes to? I've never replaced a thermostat before, so any advice would be great. Thanks guys!

[SRPWR]

The thermostat is located where the bottom hose goes on the engine. Also, on the motor where the upper hose goes is a small bleeder screw. Take that out untill coolant starts coming out of it then put it back in. Make sure you have a good radiator cap so that the engine will "burp" properly. Just be patient, it takes a while for the SR's to properly bleed.

[9240sx]

Is it better to remove the bleeder bolt and wait till the water comes out..Cause i always just remove the radiator cap and run the car without it till the air bubbles stop coming up...That seems to work,But will i bleed my system better doing to the other way?

[S13FASTBACKSR]

from personal experience, IMO..the bleeder screw seems to be less messy

[onecrazyfoo4u]

So when filling it up, you fill it from the radiator cap, until coolant comes out of the bleeder screw? Or do you fill it from the bleeder screw? Also, do you do this all while the car is running, or when it's off? Thanks for the help guys!

[gniknave]

This is for a sohc KA, but I believe the procedure is nearly identical. you might find this quoted text and the thread helpful:

Ok I assumed you knew how to bleed the car properly,my mistake.

When filling it before starting it there is a screw on the front of the intake manifold near the temp sensors, usually has a small sticker next to it. has a small brass washer under it. you remove that screw and fill it till a steady stream of coolant comes out that screw hole. Then you put the screw back in and top the radiator. Car is on an incline btw. install the bleeder funnel fill it about half way. Start the car and turn the heater on full heat and full fan speed. let the car idle till it reaches op temp. once it is in that area goose the throttle,let it come back and stabilize at idle,then goose it again,let it idle for a couple mins. Do this for about 10 or 15 mins after it reaches op temp. Just keep repeating the steps. The key here is to let it settle at idle between each goose. Without the radiator cap on the system can't really build up pressure so the goosing of the throttle from idle gives it a bit of pressure by speeding up the pump sharply[going from idle to high rpm instantaniously]. A sastianed high rpm will not achive that same effect. When you goose it you are snaping the throttle to around 4 or 5k rpm. You dont gradually apply the pedal to bring it to that rpm, you romp on it and let off.

Here's the original thread

[S13FASTBACKSR]

i didnt feel like reading that huge quote so i am just going to answer your question by telling you what i do..maybe its the same as that quote..engine off..fill system through radiator (usually less messy with a buddy if....) you have him fill it while you stand ready to install the bleeder screw once you see fluid coming out ( make sure its constant/ continuous fluid if its air bubbly then let it keep coming.) then install screw, radiator cap and your good to go

[Blown240sx]

Stab it with a knife that thing will bleed forever

[FSUDrifter]

- fill with fluid- start engine and run till at operating temp- open bleeder screw- put your face close and look in the hole

don't do that.

[onecrazyfoo4u]

Cool, thanks for the help guys. I'll probably just fill it all up, through the cap and bleed screw then start the car and continually fill it up threw both points for awhile. It'll work good enough at least, since I'm not having too big of problems overheating.

Question for you all though.....my car only overheats when going uphill, whether I'm boosting or not. I can romp the hell out of it in the city in stop and go and it never goes over half way. How can I get rid of this problem? It's only uphill during the day. Does that sound like a bad thermostat, temperature sensor, or something else? Thanks.

[S13FASTBACKSR]

hmm thats wierd..it is a possibility that you just dont have enough coolant in your system for uphill driving. If the thermostat was going bad or any other component it would overheat at all times..just try putting more coolant than normal in your system and see if that fixes it

[gniknave]

Cool, thanks for the help guys. I'll probably just fill it all up, through the cap and bleed screw then start the car and continually fill it up threw both points for awhile. It'll work good enough at least, since I'm not having too big of problems overheating.

Question for you all though.....my car only overheats when going uphill, whether I'm boosting or not. I can romp the hell out of it in the city in stop and go and it never goes over half way. How can I get rid of this problem? It's only uphill during the day. Does that sound like a bad thermostat, temperature sensor, or something else? Thanks.

Bad radiator. Take my word to Vegas.

[onecrazyfoo4u]

You think so? I wish there was a way to test radiators to see if they're flowing enough or not. It's just the stock usdm 240 radiator that came with the car. I'm going to flush the system out and clean it out good. I've got a new thermostat and coolant temp sensor to throw in there. If that doesn't work, it'll be time for a koyo radiator.

And s13fastback, there plenty of coolant in there, always has been. I have had to add any at all, so there's no leaks whatsoever. Don't know what the prob. is but it's getting anyone.

[S13FASTBACKSR]

ya sounds like maybe its time for a koyo

[FSUDrifter]

You think so? I wish there was a way to test radiators to see if they're flowing enough or not.

Yes there is a way to test them. Take it to a radiator shop. Call around using the phone book. There was one where my car was and it's a small town. The pressure and flow test it for pretty cheap. I had my koyo done before I hooked it up to my car because it came with the car used and I wanted to make sure it was safe to use.

Look at the sponsor pages for koyo prices. I swear I saw one for like $269 shipped or something the other day.

[onecrazyfoo4u]

I'll have to go get mine tested then, just to see where I stand. I'm thinking it might just be the gauge, since it's only uphill....even during the night too. Don't see how there's any way for it to overheat on a cold night, when I'm not pushing it hardly at all.

What's the normal operating temps for water temp. gauges? I'm thinking it might be a bad coolant temp sensor, the one for the gauge, not the ecu, any input?

[S13FASTBACKSR]

I was thinking the gauge too but i think the gauge would not work at all times then..your gauge needle can obviously go up and down just fine so its not like its loose and moving up when you go uphill..cuz then if it was loose it would fall down going down a bridge or so on..and the temp sensor for the gauge probably isnt bad either because the gauge works but what you can do is try to locate the power wire and check for voltage and check the ground wire for continuity.

[Steve Lloyd]

you also need to have your heater turned and the front of your car jacked up so you get fluid in the heater core as well. Otherwise, you won't completely fill up your cooling system and this could be why you are getting hotter going uphill.

[oscars13]

hey guys that screw that ur supposed to bleed the system with broke on my s13, any ideas?

[Emperor_Tha]

get a matco spill free funnel $25. its goes on the opening of the radiator just add fluid and let the car run. its automatically let the air out from the opening off the funnel when the car is running. also there is no mess. whatever if left in the funnel just but it in the coolant tank.

[Emperor_Tha]

hey guys that screw that ur supposed to bleed the system with broke on my s13, any ideas?

if its not leaking, then you are good. if you want to bleed your system just get a matco spill-free funnel.

[youngun21a]

Mine broke too and it's leaking a little,any ideas thanks.