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Water leak

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L

LLAngus

Jedi Knight
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My 73 B GT has become a daily runner. I travel back and forth to work, some on the freeway. I noticed every once in a while the temp guage would go just past half way and I would add some water to the radiator and the guage would go back to normal. Tonight I went out to do chores and had to use a flash light to see. I found a water spot under the GT, so I crawled under the front end to see where the water came from. It was coming from the overflow tube and dripping on the driveway. I now know I need to change the radiator cap. /ubbthreads/images/graemlins/lol.gif /ubbthreads/images/graemlins/driving.gif
 
No you don't. You're overfilling the radiator and it is rightly expelling from the overflow tube. The cap is working fine. The temp gauge going "just past half way" isn't a problem at all.
 
How much coolant are you adding? How often? The radiator cap can be tested with the same tool that is used to pressure test the cooling system.
 
The water goes down below the cooling fins. This is too much to be safe. I am going to get an overflow bottle from the Midget (one that is extra) and put it on the GT.
 
I let the water go down so I could see how much is pushed out. It took over 3/4 gal to refill the radiator. (I bought a gallon of Geyser Spring so I could measure and it took almost the whole jug. I bought a radiator cap at the local NAPA parts store. It will be in tomorrow. I am still going to put in an overflow tank. So far, I'm into the B GT less than $300 and the enjoyment factor is way over that. /ubbthreads/images/graemlins/driving.gif
 
Get a 15lb cap when you get one.
 
Tony, Teh parts house sent a 9 # cap and said it was the right one. After replacing the old one, I drove to Willits and back. Tonight when I got home from work it sounded like girgling in the water system and the water is at least a half gallon low again. I think it is still coming out the overflow tube but it is raining here and I can't see any water on the ground vs the rain. Why did you say to use a 15# cap? /ubbthreads/images/graemlins/crazyeyes.gif
 
I've an old original owners manual for GHN4 & GHN5 cars. Its ays:

"The system is pressurized to 10lb./sq. in. when hot."

I may be wrong - & don't want to put out bad info - but IMHO a 10lb cap would maintain that pressure in an entirely new system...as things get older, I think increasing the cap pressure would ensure 10lbs....maybe not...but, I have 15lb caps on several of my cars & haven't had problems
 
The girgling bothers me, it stops after putting in h2o but I still don't like it. Would a overflow tank help??
 
You don't have one? Oh, wait, I'm sorry - your car didn't have one....I've got a dumb question...is your heater control all the way closed?
 
No, great warmth in the cabin and defrost works. I looked at the heater valve and it is definitely open.
 
Found the apparent problem. There is a problem with the head gasket. After going sown the driveway I turned around to check and fill the radiator. When I took off the cap a rush of air came out. There should have not been any pressure build up that soon. Check with my favorite radiator shop and he told me that it is most likely a bad head gasket. There is now moisture coming out of the tail pipe(steam) if I start up the GT right after (less than 5 minutes) shutting down. Am I on the right track?? /ubbthreads/images/graemlins/cryin.gif
 
Been there a few times. Sounds like typical head gasket. In that short a drive I believe it must be a blown gasket but you should have the radiator guy pressure check to be sure. Me, I'd just pull the head and do the change, but I may have a bit more experience. FWIW,
Guinn
 
I've got a shop full of tools from drag racing days. Just have to move the wood working machines out of the way to get the GT in the garage. I think it should be an easy days job--two coffee pots--since I don't drink. /ubbthreads/images/graemlins/computer.gif
 
Four hours tops, if you plan the mission well. Still a "two pot" job tho /ubbthreads/images/graemlins/wink.gif
 
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