Eiyse98ls1

finished installing new waterpump and went to flush the rest of the system with water.. now after a couple of minutes water comes quick to the top of radiator (cap off) and just go everywhere (boiling hot). any idea whats happening here? tstat stuck closed? also inlet hosed completly flat like it created a vacum? im using a quick fill raditor funnel doesnt seem that its the problem same thing happens with out the funnel...


thanks

fatjet00

Sounds like you have air in it. Whenever I fill up a radiator I pour the coolant and water in real slow, when it gets to the top of radiator fill neck I stop filling and then squeeze the upper radiator hose to try and purge air out of it. Then I start the engine with rad cap off and top the antifreeze off, then install the rad cap. Go out for a drive, let it cool off then re-check the fluid level. If you try this and it's still boiling out the rad cap, then it's probably you're thermostat stuck closed. Good luck with it.

Cole Train

iTrader: (30)

you NEED to REPLACE your radiator cap. Do it with a GM only one. Others don't seem to seal as good. I had my '96 Z28 do that and replaced the cap and NEVER happened again.~Cole~

Eiyse98ls1

well this it without the radiator cap on.. this is actually happening as im trying to let air out of the system without the radiator cap installed and car on. i fill the radiator, let the cooalnt drop, check for air bubbles coming up top, fill somemore to the top when it level goes down and all of a sudden it comes up and spews everywhere boiling hot.

thanks for the help

Eiyse98ls1

i have a new radiator cap. at the moment im trying to let all the air bubbles out by not putting the cap on.. why would it just boil over? should the level just stay close to the top or drop? if it over flows would that be a sign of stuck closed t-stat?
im using a new waterpump from gm w/ a new tstat already install with the pump, new upper and lower hoses and have the new gm radiator cap.

if i put the cap on wouldnt just fill the resevior and overflow from there.


thanks for the help

Cole Train

iTrader: (30)

Yeah it "should" bubble into the overflow. If it's not then i'm not 100% sure why then. I was reading it, thinking it was bubbling outta the OVERFLOW not the cap. It will bubble out the radiator if you leave if off and all the air is outta it. especially if the overflow tank is full. Put the cap on the radiator, good and tight, and run the car. The system will boil easily if it's not pressurised. With the cap off it will boil very rapidly. I would fill the system to your best ability. Put the cap on the radiator, run for a while and see if the overflow tank is filling up at all or if it's going down. It will work the air out eventually and will keep pulling coolant from the overflow until the system is full. Then just keep adding fluid. I DOUBT highly that the t-stat is bad. That'd be a RARE occasion especially new. but like i said, put all caps on and fill overflow tank to where it's supposed to be cold. Then let the car run and see if it goes up or down. If it goes down then there is air in the system and it will eventually work it's way into the overflow (burp itself) and the coolant level will drop. This may take a while but be patient. These systems need to be pressurized in order to work properly.With the Rad. cap off it can't pressurize and will boil over. Try what i said and see how that goes. If that doesn't work, come back to us~Cole~

Cole Train

iTrader: (30)

Hope that helps by the way. I had a hell of a time figuring out my problem on my '96 Z28 and then i figured it was the Radiator cap and it fixed it right away. I'm just trying to help out a fellow GM hobbiest

Eiyse98ls1

thanks for your help.. im going to try it agian tommorrow after work.. i was on it for 3 hrs and started getting tired and hungry. its just wierd to me because i didnt remember this happening to me when i changed my tstat way back.. i didnt think the cap had to be on and system pressurized.. also im still running just water becuase i want to completly clear the system out..

ponygt65

R U sure the impeller on the water pump is flowing eht right way.

Cap it, top it off like has been suggested...should be good.

chavez885

iTrader: (12)

ponygt,you better take your butt back to the street racing section

Eiyse98ls1

i hope so, the impeller should spin whatever way it has to if installed correctly, right?.

Eiyse98ls1

well just finished up and all is good..

drained radiator, pulled hoses to heater core from wp, pulled lower hose, reattached filled with staight cooalnt since i had mainly water in the system, let her warm up, turned off endine, filled rafitor up agian then cap off and let her run for a while then it started to run hot, turned of let her cool down, added coolant, turned her back on and let her idle for 30mins no issues.

thank s for the help agian.