Jwwesttx

so finally finished my lsx swap, double checked everything, primed the block prior to starting it, it fired right up no leaks , good oil pressure soubded great, i filled the coolant reservoir before firing it up and left to cap off and let it run, im running a 160 thermostat, as the car idled temperature kept rising and coolant was bubbling out of reservoir, i let temps get up to 220 and shut it down, after shutting the car f i heard the fluid making its was down but im thinking mayby the thermostat didnt open?
iv never had this issue usually i just start it let it run with cap off and keep topping it off, any suggestions?

thanks

double06

I usually bleed the system a different way. I take a plews suction gun (look like a big seringe) to the little hose (5/16 or 3/8 id hose) that is on front of your over flow tank and suck the water through that. It sucks the water from the other side of the thermostat you will get air for a while and then boom antifreeze. You just need to keep filling the overflow tank as it sucks the water through system.

Jwwesttx

will that work if my block is brand new and never had coolant in it? will it suck the thermostat open?

1972bluelt1

Is that the hose that goes to the air bleed pipe just under the intake manifold?

double06

No it is the hose that goes to the plastic coolant tank from the radiator it is at the end closer to radiator. About 8 inches from the fill cap toward the bumper.

Jwwesttx

Jwwesttx

do you do it with the engine off?

double06

Yes it should get you there enough so that you can run the motor and let its do it thing. I have done 2 head changes and each time this method gets me within a few ounces of a full fill. It is basically sucking fluid through the system.

double06

Yes that is the hose and do it with engine off. Get the plews gun they are handy for other things too.

Jwwesttx

thanks il give it a shot, i have done 2 head swaps and cam swaps on my car and never had this issue either so hopefully it works if not il change thermostat i have a feeling its stuck not letting coolant through

double06

Don't be surprised if it sucks a gallon or so out of your overflow tank before you actually get antifreeze went you get anti freeze out of the tube you are done. I hold plews gun just above the overflow tank.

Jwwesttx

thanks il try to find one of those guns today and try it out

1972bluelt1

great info. Thanks.

pcguy2u

Getting ready to fire up my restomod project and this is good info...

big_mike_eu

Thank you, very good info. Will come in handy in about a month when I get the new cam and redone heads.

How do you guys know how much water to mix with the coolant? Assuming there's some left in the block. Do you premix a 50/50 solution?

Apocolipse

If u take heads off and drain rad, about 50% coolant capacity is left in the block.

I usually take off the upper rad hose on the radiator, pour water down it so it fills the block/cyl heads, then when thats full I get a funnel and pour remainder into rad. All that is left is a topup in the overflow tank and you are good.

No fear of running engine without coolant.

Jwwesttx

thanks i just tried pulling the upper radiator hose and filling it and pufting it back on, i ran my car with reservoir cap off and still same thing, it starts bubbling and overflowing reservoir but my coolant temp is already at 225 so its like its not cooling the block? any other suggestions?

Jwwesttx

and when i shut the car off the hose going to the upper part of the rad is hot but going to the thermostat is still cold?

Apocolipse

Close the cap...you are boiling the fluid without having pressure. Turn the heat on in ur car...if its blowing warm you are circulating the water.

Jwwesttx

i had the heater on and it was blowing cold but i had the cap off il try it again with the cap on

thanks