air probably in there
Pukes Water
Thread Starter
Intermediate
Joined: Jul 2000
Posts: 40
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From: rochester n y monroe
Pukes Water
Hi Guys. What Causes The Car To Puke Water Out Of The Expantion Tank After The Car Is Shut Down. Water Pump Radiator And Thermostat Appear To Be Ok Because Temp Is Ok When Driving. Only Happens After Car Is Parked. I Have Only A 12lb Pound Cap On Because The Radiator Is Origional Is This The Problem?
Advanced
Joined: Aug 2000
Posts: 75
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From: Hamilton, OH USA
I have had similar problems, and have seen posts on this before. I believe it may be the positioning of your upper radiator hose in relation to your radiator cap. From what I remember from the threads, if the hose is positioned above the radiator cap, a siphon can be created that sucks coolant out of the overflow tube. I have loosened the clamps on my upper radiator hose and rotated it down slightly, and have not experienced the problem lately. Any other members recall this thread?
Instructor
Joined: Jul 2003
Posts: 210
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From: eaton rapids mi
I had this happen to a previous car of mine where it would gurgle into the overflow tank after turning car off and it turned out to be a blown head gasket.
Since you have an original rad then i would assume that the top hose should be at or below the cap. As suggested above make sure that your hose has not somehow arched above the rad cap.
Since you have an original rad then i would assume that the top hose should be at or below the cap. As suggested above make sure that your hose has not somehow arched above the rad cap.
Team Owner
Joined: Jul 1999
Posts: 26,545
Likes: 46
From: Huntersville NC
What year is your vette? First of all, the car is going to get hotter after you shut it off. This is because the fan stops sucking air and the waterpump stops circulating water. Meanwhile, the engine remains hot for a while. The car belching out some excess water could be caused by something as simple as the radiator being overfilled. 
Actually, I used to have this problem all the time. Car was also running a bit hot (210-215...) I did ALL the things we do to make the vette run cooler. I improved things in tiny increments. Meanwhile, I added a plastic overflow can so I wouldnt pish all over the garage floor, or the driveway, or wherever else I happened to stop. I finally figured out I was overfilling - The 68 service manual tells you to fill the radiator only up to 3" below the filler neck... try sticking a ruler down there - 3" is much more space than you would typically give yourself. The plastic can was a great stopgap measure, but now I almost never see any coolant in there at all! The last thing I did that had a major impact on engine temp was to install coated headers. Really cooled down the engine.
Actually, I used to have this problem all the time. Car was also running a bit hot (210-215...) I did ALL the things we do to make the vette run cooler. I improved things in tiny increments. Meanwhile, I added a plastic overflow can so I wouldnt pish all over the garage floor, or the driveway, or wherever else I happened to stop. I finally figured out I was overfilling - The 68 service manual tells you to fill the radiator only up to 3" below the filler neck... try sticking a ruler down there - 3" is much more space than you would typically give yourself. The plastic can was a great stopgap measure, but now I almost never see any coolant in there at all!
The last thing I did that had a major impact on engine temp was to install coated headers. Really cooled down the engine.
Last edited by PRNDL; Aug 18, 2004 at 09:14 PM.
Thread Starter
Intermediate
Joined: Jul 2000
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From: rochester n y monroe
Thanks for the replies. This car is a 72 with the expantion tank the radiator is sealed. My upper hose is definitely above the tank and is not filled with water. I have tried to get it lower than the tank but I havent been successful.Maybe I have the wrong upper hose this one has a "s" type shape. I will give it another go. Thanks for the replies
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
I'll give this one a try. The rad should be an aluminum sealed unit such as:
And the overflow tank should look something like this. I assume the "puking" is via that vertical hose at the neck. I see two reasons for that to happen. The tank is more than 1/2 full when cold. Or the rad cap is not restricting pressure (and coolant) to the entry of that hose. The standard cap is 15 psi. Yours at 12psi may not be enough or the lower rubber gasket on it may not be sealing properly. Hope this helps.
And the overflow tank should look something like this. I assume the "puking" is via that vertical hose at the neck. I see two reasons for that to happen. The tank is more than 1/2 full when cold. Or the rad cap is not restricting pressure (and coolant) to the entry of that hose. The standard cap is 15 psi. Yours at 12psi may not be enough or the lower rubber gasket on it may not be sealing properly. Hope this helps.
Last edited by Paul L; Aug 20, 2004 at 09:07 AM.
Thread Starter
Intermediate
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From: rochester n y monroe
Thanks for the reply Paul. That is a sweet looking ride!!! You are correct this is the same set up. My upper hose is not as straight as yours it has a rather pronounced S shape thus that may be my problem. I know for a fact that it is higher than the tank brcause I tried to back fill thae hose and when I did that it over filled the expantion tank. My guess is that my problem is a combo of 1 air in the system and 2 a very low pressure cap. When I first rebuilt the car I had the heater core let loose so I got freaky about the old origional radiator and went with the low # cap.
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Instructor
Joined: Jun 2004
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Had the same problem with my BB. I was directed to lower the upper hose as low as possible. It seems if the hose is higher than the expansion tank, the tank fills up with fluid and the hose becomes the expansion tank. When the car is shut down it continues to heat up a bit causing the already full expansion tank to relieve pressure out the overflow. My hose is routed differently from yours but rerouting it worked for me.
Le Mans Master
Joined: Jan 2001
Posts: 6,938
Likes: 1
From: San Diego CA
Mine is routed just like Paul's, my car likes the level between low and high. If I try to fill to the hi mark it 'pukes" it out when shut off then I'm fine for another year till it's time to change the coolant. I haven't checked the coolant for months but it's fine. She knows exactly what she needs and i leave it up to the car to determine the level.
Le Mans Master
Joined: Sep 2000
Posts: 5,635
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From: Orlando Floriduh
Air goes to the highest point. If the highest point in the system is anywhere other than the cap, Air, as it expands will force water out of the tank. The cap MUST be the highest point of a closed system or water will vent, MORE air will get in as it cools and then more water will be forced out. A viscious circle has begun an when you add more water the cycle starts over. Physics at work....
Racer
Joined: Dec 2003
Posts: 275
Likes: 6
From: NY
I have a BB. I wrote the posts I think you are referring to titled "Coolant on the Ground". The return hose to the rad has NO clearance. If you twist it, you can get inches of clearance, just like I did. BUT that puts the bend in the hose ABOVE the rad cap. This is an air gap that heats up to syst temps. A gas EXPANDS 1000's of times more than a liquid and a liquid can't be compressed. The radiator cap LOSES and the "Coolant on the Ground" ensues. I got this info from corvette.faq, it would have taken me YEARS to figure out this one on my own. You have to find rad hose clearance some other way.
Thread Starter
Intermediate
Joined: Jul 2000
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From: rochester n y monroe
You guys was right. I had the wrong hose on. Went to local parts store and bought the right one which was much more straight and it seems like I am good to go. Thanks all for the great advise