STILL overheating...any advice?

[mother_of_a_drifter]

My son has an 89 240 KA, a couple of weeks ago it started overheating. We live in Phoenix, and being that I have been a Phoenician nearly all of my life I am not unfamiliar with the interworkings of the average cooling system on a car.

Here is what we have done, and what I'm looking for are suggestions, of any kind.

Replaced:
Fan cluth
thermostat
upper and lower hoses
thermostat sending unit
radiator
(flushed cooling system prior to installing new item)
70/30 ratio on the antifreeze
burped the cooling system - ran the car with the heater and defroster on, unscrewed the bolt on the top of the block and waited for the bubbles to come out, opened the radiator cap and added water until the antifreeze came out the small hole.

The water is flowing, the fan is on a switch and it is always on. Changed the oil it is real clear, not milky.

This happens with our without the a/c running, day or night. To say that I am frustrated would be the understatement of the century. My son starts school again next week and we can't have him breaking down.

So, lemme hear it...I'm all ears.
oh, and thanks in advance.

[AZ89two4Tsx]

Have you tried just running without the thermostat?

Is the fan shroud in place?

How do you know it's overheating? If you're just going by the gauge, I would invest in an aftermarket temp gauge. The oem ones are notorious for being inaccurate and usually by the time it overheats, it's too late.

If you're running a fan clutch, what is being run by a switch?

...Btw, the car you guys have doesn't happen to be a gray sil80 does it? J/w, I can never find the owner of my old car.....

[Razi]

Here's a good post from PAHC.

If it worked without the T-Stat it tell me the pump is working you should.

Replace the T-stat again, installed facing the correct way with the bleed vent on the top. I actually prefer a 1/4 hole drilled in the top. But do this only once you verify that it is working. (put in a pt of water and heat it up and make sure it opens (should happen right before boiling)).

Then pressure test the system for 30 min at 1.3bar and make sure its holding pressure.

Fill and bleed

Check radiator cap (store can do it)
Pressure test the systems
Then bleed it.

Coolant bleeding

Jack the front of the car up front tires off the ground 4-6 inches.
Take off radiator cap
Take a 2 liter pepsi bottle cut it in half and use some black electrical tape and wrap the bottle neck a little, or get a cooling funnel
Flip it around and place the bottle neck were the radiator cap was at. Pinch off over flow line if not using the funnel.
Now start filling it with coolant about half way
Remove bleeder screw
Close bleed screw after you get a nice even stream of coolant
Squeeze the upper, and lower lined and burp out the air
Add antifreeze until you over fill the rad by a quart
Turn the heat on full blast
Start the engine and let the engine run after 3-10 minutes the thermostat will open and suck in the excess antifreeze (ambient temp affects time)
Fill it again but with about a half of quart.
Let it run until no more bubbles come out. Squeeze hosed time to time.
Replace cap, unclamp overflow hose and then shut off the engine, fill over flow 1/2 to 3/4

Coolant funnel (best to have)

[mother_of_a_drifter]

I thought about pulling the thermostat, but we just got it all back together.

The belt driven fan cluth is the one we replaced. There is an aftermaket fan he installed in front of the a/c condensor that is run to a manual switch in the dash.

The shroud is intact (even has the side pieces) and clears the fan blade without any problems.

We did buy an oil and h2o gauge to mount on the column inside the car, my husband wanted after market for those too, but they have yet to be installed. Maybe it is just the cluster gauge...there doesn't seem to be any other symptoms of overheating (smell, pinging, steam...)

Thanks for the suggestion, have a great night.

This car is spray painted white, has a sun roofand the kid we bought it from was in Utah originally.

[Mercury_Hg]

Check the temp sensor with a multimeter. Check it after start up as well as after warming up fully. Report back on findings.
1991-1994-240sx-coolant-temperature-sen ... 54375.html

Check the timing too, make sure you're not running ridiculously advanced.
1991-1998-240sx-timing-light-tutorial-t358264.html

[mother_of_a_drifter]

thanks, we will try that tomorrow. I know the timing is okay, we checked that the other day, and I forgot to mention that the radiator cap was new also. Thank you for the great suggestions, we will see where we at tomorrow night.

[JKL1031]

i just got mines to run with a tstat. What i did exactly. First off i did a boil off with my tstat and a new one from the store they both opened and closed at the same times. prior to this, i drilled 4 tiny holes around the tstat. I put it in, jacked the car ran it with the RAD cap off, didnt use the bleeder. Rev'd it till it got to op temp, at 170F, (I have a water gauge.) Id day go a min. after the OEM gauge reaches op temp. U can feel if ur bottom hose is heating up, it shud and its then circulating.

[mother_of_a_drifter]

Thanks for all of the advice, I will update tonight after we check everything ONE MORE TIME.....8th time is a charm

[mother_of_a_drifter]

Took out the tstat, no overheating....the jiggle hole was about "2" oclock instead of 12 - but we just pulled it for now....we can't get it to over heat.

Plus we lifted the front end after re-assembling and burped it with the front end elevated. thanks everyone!

[JKL1031]

u dont have to burp without a tstat. how long did it take to overheat with the tstat?

U shud go ahead and drill 3 more holes around it the size of the jiggle valve. it might help you.