so what is the deal with the cooling syste. i have been reading about getting air trapped in the system, and i am getting a little concerned. i had already filled the radiator through the fill cap when i discovered the issue, should i be removing the upper hose now? also read that the engine can run for 5 minutes or so with no coolant at all, and i haven't really run it much longer than that yet. how can i be sure there is no air trapped though? will the pump circulation be enough to pull out all the air as long as i keep an eye on the levels in the radiator itself?

 

If you look inside the radiator, where the line coming from the TB is hooked up, when you see a steady stream of water coming from this line, you have all the air out of it.

At least that's how my I did my '98 when I changed the water pump.

 

I drilled a small hole in my thermostat to make sure water was getting circulated.

 

I wouldnt go 5 mins without any coolant. LSx engines heat up REALLY fast

Steam line needs to be attached to part of the pressurized system in order to function

 

yeah i didn't actually run i tthat way, just read somewhere on tech that guys have. my temp gauge is hooked up and it didn't move at all, then when i looked into the rad there was nothing coming out of the steam gauge. i hope its just that the stat was closed still. only ran it for probably 3 minutes.

 

You may already know this but since the LS engines circulates differently once you fill the radiator, take the upper hose off and prop it up and fill the engine until it spills out. If you do this you KNOW that even if there is an air pocket there is enough coolant in the engine to prevent damage.

As the others have said use the steam lines, don't cap them like some say. The pump will never pull out the trapped air but the hot/cold cycling and the steam lines will keep it in check. If you fill the engine and the radiator (while its cold), monitor the levels, you will be fine.

 

When you say your temp gauge is hooked up, do you mean the stock one in the dash? Don't go off of that gauge, mine is wired in and at operating temp it still doesn't move any. The motor could be getting warm and you'd never know if you're basing it off the stock gauge. I bought an aeroforce interceptor gauge that reads off the oBDII port, and one of the parameters I constantly have it set to is water temp.

It's hard to say if the thermostat would actually kick in and start pushing water through the system after only 3 minutes of letting it run. If you DO have air in the system, it will warm up much faster than normal. And depending on the outside air temp, it could take less time as well.

Do you know that your fans work, and at what temp? You could wait for the fan(s) to kick on and then do the feel test in the water pump hoses to make sure the coolant is circulating, and to check for a stuck thermostat.

As for filling the system, yes, take the upper hose off he radiator and fill the water pump as much as you can. Then with the car running, leave the radiator cap off and keep filling the radiator until it's full and the car is at operating temp (t stat would be kicked on).

 

ok, i will fill through the upper hose and then top off the rad while running tonight or tomorrow. should there be water constantly circulating from the steam lines then, right?

i need to check the fans situation, i can ground the relay and they kick on, but i don't think the pcm is doing it for me. its a truck pcm, and i asked the tuner to turn them on, but i'm not certain that actually happened. unfortunately i don't have a tuner yet, so i'm not sure what i'll be doing there.

 

Under the stock settings, the fans won't kick on until after the coolant starts circulating, about 5-10* hotter than when it circulates actually. So depending on what thermostat you have, it may be an even longer gap, for example if you put a 160* t stat in there, it will take longer from the time the coolant starts circulating till when the fans kick on. The stock t stats are usually a 180 or 195.

 

The 99+ LS1s temp gauge just gives a ballpark of where the temp is, the '97-'98 is the only one that gives actual water temp on the gauge.

Are you using a 4th gen rad or a 3rd gen?