Problems with Bleeding the Cooling System

[hamsterball]

Hello,

This is on a KA24E, Nissan 240SX 1990. I am using the bleeder screw hole that is on the intake manifold in front of the connection of the upper radiator hose of course.

My bleed procedure:- Car is completely cold

- Take radiator cap off and unscrew bleeder screw.

- Turn car on.

- Car heater is on hot all the way.

And when I used to bleed it before I installed a new thermostat, it used to go like this:

First the radiator cap hole overflows, so I put the radiator cap back on.

Then after a couple minutes, I see coolant spit out of the bleeder hole, and then I put the screw back on.And it wouldn't overheat.

At the current moment that is not happening.

As soon as the car starts (this is on level ground btw, I tried doing it on my slanted driveway, but the same thing happens)..

The radiator fluid doesn't start overflowing.

The bleeder screw starts overflowing and you can see bubbles in the fluid.And coolant just keeps spitting and flying and flowing out of the hole until there isn't enough fluid to flow out of it.

Then I plug the bleeder valve when I see that, and top off the radiator.Then the radiator starst overflowing so I cap the radiator.

And then you think you're all done, but it still overheats after driving.

Every single time I do it, it's the same scenario..

Notes on car:- Fan clutch is fine, but doesn't have too much resistance.

- New radiator, new thermostat, new upper and lower hoses (upper hose a few montsh ago, lower hose a year ago)

- No leaking. Shroud is cracked but on securely

Why is the air not bleeding? Why does the coolant start overflowing out of the bleeder hole before the radiator cap hole?

Please help me out. Thanks

[s13sr20chris]

heres how i do it.

attach burp funnel or other device.

jack up front end.

unscrew bleeder.

fill with coolant.

screw bleeder.

more coolant.

unscrew bleeder untill straight coolant comes out and tighten.

start up with heat on full blast.

occassionally rev and hold.

[hamsterball]

I see.This technician at work (Master Heavy Line Tech at Ford) told me to (with the car off) take off the bleeder screw and radiator cap.then to fill the radiator cap until coolant spills out of the bleeder screw hole.Then plug the bleeder hole back with the screw, and then to top off radiator and close the radiator cap.(same thing you said)

he said it should be fine right after that.That is what I did and it doesn't seem to be overheating after a light 5 min. drive around town like before, but I'm sensing that the engine is running hot.Because, usually when the car overheats, the idle will shoot up gradually up to around 1200RPM.

Is that normal for KA's? The idle shoots up while overheating to spin the fan clutch faster right?(I know on most cars with electric fans, the idle goes down when the engine gets hotter).

Also, he said not to turn the car on, that I don't need to.He mentioned that keeping the cap and screw out while the car is running just circulates air through the system more.

Can anybody else confirm this?

*EDIT*

I re-read your post and realized that you only have ONE *passageway for air* open (which is your radiator cap hole with a funnel).

My car has been sitting after the 5 min drive for 15 min.it is not overheating because the temp gauge reads a TINY TINY bit before the half way mark, but now the idle is at 1000RPM (I bet if I drive it hard now it will overheat. )

I'm going to try your method when the car cools down if it overheats after a "test drive"
Modified by hamsterball at 9:44 PM 11/3/2005

[hamsterball]

Okay well I tried the big funnel acting as overflow tank method, exactly as you typed.

The coolant started flowing up the funnel, then the thermostat opened and it went down.It did this a few times before the coolant in the funnel started boiling.

I think I need some more instructions because it got kind of out of control and started spitting everywhere and all over the engine..And then the engine started overheating.

I turned it off and as soon as the water went down the funnel I capped the radiator.

Turned the car back on a minute later, wasn't overheating, and it's been on for 3 min.

Not overheating.

Please, more instructions lol.

what do you do when the coolant in the funnel starts boiling?

[hamsterball]

Okay I tried the funnel method again when the car was cold.

And some bubbles came up, and then it started steaming and getting hot.

I had to rev the car to make it go down and then capped the radiator.

I drove the car around, and it started running hot on the freeway!Then when I came to a stop, of course the gauge went up.

drove it home overheating for 3 min.Got home and held the gas to 2000RPM.

To my surprise, the temp gauge was going down!After that, it stayed at like 4-5 notches.

I revved it to 3000RPM, and held it.It then went down some more, it was like 3/4 of a notch away from being at normal temperature!

As soon as i let off the gas, the gauge started going up again gradually.

Is it alright to guess that this brand new thermostat is not opening?It's the OEM 170 degree thermostat.

[s13sr20chris]

bro that does sound like a sticking thermostat. i would try another thermostat. oem means dealer right?

[jdm_master_X]

thermostat was placed in the right way correct?

well, test the thermostat by putting it in a pot of boiling water, and if it expands its good.

my method of bleeding the air is everything listed above, but i occasionally squeeze the upper hose to let the hard to escape bubbles out, i let it sit and i squeeze every now and then. the air bubbles disappear for me after 3-6 minutes. then i shut the car off. thats how it worked for me.

good luck!

oh...im assuming ur cooling system isnt infested with "cancer".

[hamsterball]

OEM means Kragen $12 thermostat bought for internet price of $7.

Dealership thermostat, no

I still have my old one, I replaced it because I thought it was the cause of my intermittent overheating.(It turns out my thermostat housing had a crack in it, I replaced that too.That could have been teh cause of my overheating since our cars like to trap air)

I'll check my old one in a pot of boiling water.

It's at my dealership right now, I'll probably take a stab at the car when there aren't any customers around.

Thanks for the thermostat confirmation.