Coolant Spill from Recovery Tank --(Repost with additional info) Any Idea Why?

[cajuncorvette]

What would cause a car to spill coolant from the recovery tank moments after it is started and then turned off? In other words, say you started the car from cold and backed it out the garage -- the car ran for a minute or two tops. Then, after a while of sitting, there is coolant underneath. The car engine never really got warm. Then, you receive a coolant low light when you take the car down the road a few miles. The light flickers on and off.
You add water to top off the recovery tank and proceed to drive for an hour and a half at speeds of 65 to 70 and in bumper-to bumper city traffic. Coolant temps range from 178 to 210 during this trip -- higher in city traffic.
You reach your destination and stop the car for 10 minutes. When you return, there is coolant spillage from the recovery tank. You move the car to another parking place, and after exiting the car, you actually see coolant spurting out in short "gulps" from under the coolant recovery tank area -- perhaps two or three short gulps. Car has never done anything like this before -- seems to have started out of nowhere. Car never overheated and drove fine. Oil stick is clean as new -- so is coolant. What should I ask my mechanic to check?
Thanks for allowing me to repost and clarify the situation. Newbie here
Happy Thanksgiving to you all.

 

[Paul Higg]

Is your radiator cap rusty?

 

[tonylong]

Has anything happened to allow air to enter the system?
Like did you drain the coolant? Replace hoses, etc?
First - do a pressure test, using a proper tool.
Fix any leaks.
then:
"Burp" the system to remove air:
With engine cold
remove cap
fill with coolant
fill overflow tank to mark, or a little above
run engine with cap off until coolant rises and starts to spill over
QUICKLY REPLACE CAP WEAR GLOVES FLUID IS HOTTT
let it cool down
recheck coolant in radiator and overflow tank
repeat until levels are normal in rad and tank
go for drive and observe temp and "Low Coolant" alarm.
You may have to re-burp several times to purge all the air.

 

[JAKE]

TPIS recommends a similiar procedure, they call it "packing".

Have a jug of 50/50 mixture of water/coolant close where you can easily reach. I sit mine in the passenger side headlight well.

First you fire the engine and once a small amount of heat begins to build, as it's idling slowly remove the radiator cap. You'll soon begin to see the coolant begin to move around which'll happen just as the thermostat begins to open.

Once you're sure the stat has opened, reach over with one hand onto the throttle body and bring the RPMs up to around 2000/2500 or so. When you do this the coolant level in the radiator will drop. You'll see it actually disappear.

Now, while continuing to hold the RPMs at 2000/2500 or so, grab your coolant jug and begin pouring it into the radiator until it reaches the top and just begins to over-flow. BE CAREFUL NOT TO LET THE RPMS DROP OR YOU'LL GET A HOT COOLANT BATH.

Once the radiator takes all the coolant it can, and while still holding the R's up, replace the radiator cap and make sure the little arrows on the cap point at the over-flow hose.

Release the TB lever and let the RPMs return to idle and you're done. Any coolant that's too much will automatically be forced into the over-flow resevoir.

TPIS also recommends drilling two small holes in the thermostat. Those greatly help in getting all the air out of the system. I'll bet that just "packing" the system will solve your problem, unless you actually have a leak somewhere.

Hope this helps.

Jake