Puking overflow

[wetdog]

Getting the bugs out of my build everything ok except for one nagging problem , when I stop overflow pukes coolant ..engine runs at 185 195 deg. cap was changed to a 16# one ,put car on angle and removed temp sensor from intake to bleed air . Every time i pull in from a run it dumps coolant , the overflow is a zirgo unit that holds just less than a qt. could this be too small? has anyone had this problem ? I am all ears to a solution..WD

[wetdog]

Now Iam thinking I have a stubborn air pocket somewhere I have read about drilling 1/8 in hole in the thermostat to help bleed system has anyone done this?

[vector1]

lot of people put a hole in the thermostat. usually one, maybe two 180 deg. apart, up and down as installed, 3/32" is what stewart puts in theirs. if your cap is on the pressure side or outlet from the waterpump you have to hold the pressure of the water from the water pump plus the pressure from the heat buildup, i wouldn't be afraid to use a 20-24# cap myself if everything is in good working order.

[Double Venom]

WD,
Just a thought-if you have a heater core, not one Heater Core company that I am familiar with will warranty any of their cores over 16lbs.! 16lb. plus will normally blow a core-been there.........
DV

[wetdog]

I just came in from garage and jacked up car nose first and added about 2 qts of coolant , by adding slowly and squeezing hoses I was able to burp alot of air. I am going to give it more time and hopefully that will do it ..thanks for the help all ...WD

[kitcarbp]

Dont increase the pressure cap rating, keep it in the 10-12 psi range. Do you have the cooling system designed to have a large enough expansion tank volume? The over flow tank should not really be used as your expansion tank. If you have trapped air after the initial fill, you will notice the overflow tank liquid volume will drop after a few heat-cool cycles if the cooling system is desiged properly to vent entrapped air. Then you top-up the overflow tank to ensure there is always a minimum liquid level. Yes adding the small hole to the thermostat helps during initial fill and intial start-up to help move air to your surge tank/expansion tank so it can be purged to the overflow tank. I installed a thumb screw bleed valve at the highest point of my system (therm outlet neck) to aid in getting air out during the filling process.

[wetdog]

Well I have learned that I had a rather large steam bubble that was somewhere in the engine, my procedure filling the coolant in with the car at an angle worked ! it took a while but I got it full .I then put an inch of coolant in the tank and ran it no puking and 185/ 195 all day after it cools I will check level in tank and add if need be . I also went to the 13 # cap again with no problem ..Thanks again guys WD