LS1 TJ

Working on my L92 swap into the Nova.

I hooked up the radiator and heater hoses tonight. Filled the radiator with water and started it up. Ran great. Then it started pushing water out of the radiator filler neck. About the same time the fan which is controlled by the PCM started. Shut it off.

Then I pulled the upper hose off and filled as much as I could. Restarted it and the same thing after a short time. The fan came on and water pushed out of the filler neck.

Thought stuck thermostat. Had another on the shelf. Put it in, same results.

Restarted again and this time put the radiator cap on. It built pressure in the upper hose quickly and somewhat slowly in the lower. After a few minutes I turned it off.

New water pump. New radiator. New heater core. All F body accessories on the 2009 L92.

I filled it up and letting it set over night. Any thoughts anyone. Need help!

This is my fourth LS swap. Never had a problem like this.

-Joseph-

iTrader: (12)

Is it completely full of coolant? I've had to take the coolant sensor out on many cars and let air bleed out before starting to "help" get a good block fill. From that point never had a problem.

One other thing I've been meaning to check on other cars is if you have a heater hose control valve it may not be letting coolant circulate good in the block. Since the thermostat is on the inlet side of the water pump, the only way for hot coolant to reach it is through the heater hose circulation. I may be overlooking an internal thermostat bypass and again I need to confirm that on one of my water pumps, but just a thought that might help point you in the right direction.

LS1 TJ

Thanks for the quick reply. The Nova heater just flows straight thru. No valve in either heater hose line.

Do just pull the temp sensor and fill until water runs out? While the engine is off I assume?

Thanks again.

-Joseph-

iTrader: (12)

That's what I do, take it out before starting. I install a lot of new engines and thermostats at the same time and they need all the help they can get the "first" time opening. Sometimes if I know the cooling system is completely full, I will let the car get to 210F and shut it off and let it sit. That gives it time for the coolant/block to heatsoak a bit and sometimes just sitting opens the thermostat.

You can also take loose the coolant bleed pipe afterwards and that seems to help also, keep filling the radiator until coolant runs out the bleed pipe holes then reinstall the pipe. If you do this, put the coolant bleed pipe bolts back in a few threads so that coolant doesn't fill up the bolt hole.

MikeJTR

You may want to try this part:


You can get it from this link:
http://www.jagsthatrun.com/Pages/Par...ightGlass.html

andrew69_04

iTrader: (148)

sounds like you have a big air pocket somewhere. LS1's can be a pain sometimes to get the air out. usually i will fill the block through the upper hose with the steam line crossover open to let all the air push out the top of the motor. then hook everything up and let it run. works everytime

bozzhawg

If all the other parts are new.... its no big deal bro, you just need to bleed the coolant system... sounds like you got an air pocket


try this bro....... after you fill the block completely...
rock the car a bit.... you may even hear or see a few bubbles...
then fill the radiator...
start the car, with the rad cap off and let it run a bit and get warm...
If the coolant is not running through the radiator... get in the car and rev it slightly, with the cap off, now some coolant may bubble out but that usually works that air pocket out.... now don't rev it through the roof.... and let it run a bit with the cap off until you see coolant running through the radiator.... When it starts running, the coolant level in the radiator probably will drop a bit... when it drops and you have running flow, fill the radiator to the top or the desinated coolant line ....

Also I lay some towels around the filler cap so I don't get coolant on my battery, it will make a little mess but it should get the air pocket out... What some guys do also is stick the funnel in the filler cap location on the radiator and the air pockets bleed and bubble inside the funnel......

remember the air pockets usually always go to th highest point of the system.... I have sat and watch tons of cars when I ve done radiator changes or coolant changes etc... and you would be surprised of the air pockets in the system...

3pedals

iTrader: (3)

my solution was to remove the thermostat, and drill 4, 3/16" holes around the outside of the thermostat, just inside the gasket. this allows some coolant to flow through and prevent airlock. works AWESOME. ABSOLUTELY no more airlock issues.
Barrett

LS1 TJ

I got to say all of you guys are the best!

No really I am the paranoid guy since the whole world is out to get you!

I came home tonight and thought I may have left part of the shipping cover in the lower radiator outlet. Pulled it off and everything was clear.

Pulled the thermostat and thought "drill holes around the edge" and I did.

It worked perfect! Temp came up, fan turned on and the thermostat opened and the cross flow in the radiator was very evident.

Now let's get St.Cloud Guy's oil leak fixed!

Thanks again.