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How do I bleed the cooling system?



coolone said:
Well, we know an engine doesn't overheat that fast, unless completely dry... So the assumptions must be made.

1. There is coolant in the system.
2. The thermostat is working correctly.
3. The water pump is circulating the coolant.
4. Air has been removed from the system.

Is all it takes... So if your temp gauge is climbing immediately like that and the other assumptions are not probed false then you just move on to the next hypothesis.

1. The temp sensor is bad.
2. The wiring is bad (sensor to pcm).

None of this means the engine is actually running hot, but if sensor is reporting it as such, will cause the pcm to put engine into limp mode.

Check the sensors, I'd have to look it up to check resistance value. And replacing it doesn't mean the second one is good either... Lol. But shotgunning parts at a problem sucks too. Are you sure when you broke the sensor, you didn't do damage to the wiring at the plug/wire which attaches to the sensor? Can't be running hot like that unless you left something in there blocking coolant flow. When you filled coolant and started engine with radiator cap open (thermostat removed), water was moving?
Click to expand...

I moved the pigtail from my gt to the GTP with the same results too. The lim was off and my father was trying to bang it on the table a little to knock any crud out and he didn't realize the sensor was on there and broke the plastic clip and such.

I put the coolant o-rings to the supercharger on and then the supercharger gasket itself, don't know what could be blocking anything.
 
Brammer said:
The old one was thrown away. Just removed the new one and got a replacement, same results on this one too...

Any other good ideas? Removing the thermostat and running it without one it did the same thing.
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could you actually see the coolant circulating ?
 
its got to be the sensor or its wires. see if the t stat housing is even hot when the needle hits the red, i bet its ice cold still.

and are the fans coming on? cause the sensor has two parts, one signal to your dash, the other to the pcm. if it was that hot the fans would be on.
 


ScottyDoggs said:
open rad cap, rev engine. you'll see the coolant move, maybe even drop then come back up when you let off the rpm's.
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Yeah, not seeing any movement at all. Also on the other post you're correc, rad cap and all hoses stay cool and fans never turn on.
 
3 rd times a charm on the temp sensor replacement for most who change it. after market sensors suck that much.

maybe get a delco one if possible.

id just let it idle till the fans come on, check the temp of the upper hose it should get warm by the time the fans come on. once the fans are on the t stat is wide open, you should see coolant flow in the rad when reved.
 


It was the crappy BWD sensor. The guy at advance used an ohm meter to get a base read and then hit it with a lighter to see how it changed, he then looked up an ohm graph for it and sure enough both BWD sensors I had were reading in celcius.
 
Yeah, your engine would not overheat in 20 seconds, even if there wasn't any coolant in it. But glad we figured out the problem.
 
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Brammer said:
It was the crappy BWD sensor'S. The guy at advance used an ohm meter to get a base read and then hit it with a lighter to see how it changed, he then looked up an ohm graph for it and sure enough both BWD sensors I had were reading in celcius.
Click to expand...

fixed it. ...see what you get for doubting scottydoggs ? :th_biggrin2:
 


All is well for the most part! The temperature still does a little 'hunting' around at times, but I figure it just needs some further cooling, probably still has air in the lines somewhere. I might go ahead and grab a flush and fill kit and knock it out and put in anycolor or something as I noticed lots of sparkly tiny gold glitter in the coolant which most likely means the PO tried to use one of those Stop Leak products for the LIM.
 
yep , i'd do the flush. here's the official ScottyDoggs flush instructions.

how to flush coolant.


remove the t stat, put the t stat housing back on, take the upper hose off the radiator, then push it down to the ground to a bucket or let it fly.


get your garden hose out, put it in the rad turn it on, then fire up the car, let it run till clear water pumps out the top hose.


then turn the hose off, run the car till no more water comes out the upper hose. then turn it off.


put your t stat back in, with new gasket, the upper hose back on.





now take 1 gallon of full strength green antifreeze, not the 50/50 crap. ( parts store cheap green is fine to use) dump the whole gallon in the radiator, fire up the car, fill the rad with hose water till its full. top as needed till its ready to be bled of air. it will burp and take coolant as the water in the block warms up the t stat opens up for a few seconds till cold coolant hits it and it shuts again.


now to bleed the air out, let it idle rad cap off till the fans turn on, (when the fans are on the temp is over 195 deg, the t stat is wide open) then open the bleeder screw on top the t stat housing a few turns till a steady stream of coolant comes out the hole, shut the screw, top off the rad. cap it.


done.
 
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