Upper Rad Hose Problem
Thread Starter
Intermediate
Joined: Jun 2004
Posts: 34
Likes: 0
From: Raleigh NC
Upper Rad Hose Problem
My 76 will blow the upper radiator hose off if i dont keep an eye on it. It comes loose at the neck not the radiator. The hose is building up a ton of pressure. How firm is the hose suppose to be? Its like a rock. I have tried to double clamp it, run with the rad cap off to get the air out.... I dont know what to do, any suggestions?
Le Mans Master
Joined: Apr 2004
Posts: 7,106
Likes: 38
From: Newark DE
the rubber of the entire hose is hard as a rock? Replace it!
the hose should be relatively soft and pliable and easily squeezed. Most likely that's why it won't hold at the clamp either.
They aren't expensive, get a new one.
the hose should be relatively soft and pliable and easily squeezed. Most likely that's why it won't hold at the clamp either.
They aren't expensive, get a new one.
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
Is the car actually overheating?
A new hose is a good place to start. What kind of shape is the neck in? I have seen a few that corroded to a point that a hose wouldn't stay on.
If the t-stat was stuck closed he would not get pressure on that hose enough to blow it off. Look for the water flow thru the radiator to be a possible problem, if its blocked you will get back pressure enough to blow the hose. The radiator should flow good enough that there should be very little back pressure on the top hose and only during the transition when the t-stat opens and shifts the water into the radiator.
A new hose is a good place to start. What kind of shape is the neck in? I have seen a few that corroded to a point that a hose wouldn't stay on.
If the t-stat was stuck closed he would not get pressure on that hose enough to blow it off. Look for the water flow thru the radiator to be a possible problem, if its blocked you will get back pressure enough to blow the hose. The radiator should flow good enough that there should be very little back pressure on the top hose and only during the transition when the t-stat opens and shifts the water into the radiator.
Thread Starter
Intermediate
Joined: Jun 2004
Posts: 34
Likes: 0
From: Raleigh NC
sorry i wasn't clear. The hose is new, it is as hard as a rock when the car has ran for a while. The t stat is new and not stuck bc the water does flow when the cap is of and the engine is hot enough. The engine is not overheating, the gauge says 175-180 but never higher. The lower hose has the spiral wire in it, so it is not collapsing...
Pro
Joined: Nov 2004
Posts: 607
Likes: 0
From: North Alabama
Originally Posted by ngbrinkl
sorry i wasn't clear. The hose is new, it is as hard as a rock when the car has ran for a while. The t stat is new and not stuck bc the water does flow when the cap is of and the engine is hot enough. The engine is not overheating, the gauge says 175-180 but never higher. The lower hose has the spiral wire in it, so it is not collapsing...
I have had a hose blow too...turned out to be the radiator cap...it didnt release the pressure after 16lbs. Thats were I would look first. You can hook a tester up to the cap to test when it releases the pressure.
Melting Slicks
Joined: Dec 2004
Posts: 2,101
Likes: 3
From: Cruising somewhere in St. Louis, Missouri
burp the system? air pressure maybe?
How to Burp Your Car's Cooling System
--------------------------------------------------------------------------------
"Burping" the cooling system allows trapped pockets of air to escape: Air pockets can cause overheating because there will not be enough coolant in the cooling system, even if the radiator and coolant reservoir look full.
Steps:
1. Add a mixture of one-half water and one-half antifreeze to the radiator. Fill it right up to the top.
2. Fill the overflow/coolant reservoir with the same 50/50 mixture.
3. Leave the radiator cap off, turn the engine on and let it run until the radiator "burps": You will see the coolant level drop and may see or hear a large air bubble come to the top as the system burps.
4. Keep an eye on the temperature gauge throughout this process.
5. Refill the radiator to the top and coolant reservoir as needed.
6. Put the radiator cap back on.
7. Note that if the engine runs hot after this procedure there may have been another pocket of air that "burped." Let the engine cool down and then add more coolant to both the radiator and the coolant reservoir.
How to Burp Your Car's Cooling System
--------------------------------------------------------------------------------
"Burping" the cooling system allows trapped pockets of air to escape: Air pockets can cause overheating because there will not be enough coolant in the cooling system, even if the radiator and coolant reservoir look full.
Steps:
1. Add a mixture of one-half water and one-half antifreeze to the radiator. Fill it right up to the top.
2. Fill the overflow/coolant reservoir with the same 50/50 mixture.
3. Leave the radiator cap off, turn the engine on and let it run until the radiator "burps": You will see the coolant level drop and may see or hear a large air bubble come to the top as the system burps.
4. Keep an eye on the temperature gauge throughout this process.
5. Refill the radiator to the top and coolant reservoir as needed.
6. Put the radiator cap back on.
7. Note that if the engine runs hot after this procedure there may have been another pocket of air that "burped." Let the engine cool down and then add more coolant to both the radiator and the coolant reservoir.
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Melting Slicks
Joined: Oct 2004
Posts: 2,662
Likes: 8
From: Knoxville Tennessee
Put a pressure gauge on the radiator and see how much pressure you are building. It sounds like either the t-stat is not opening (remove it and see if that cures the problem) or you have a cracked head or blown head gasket; pressure from the engine is getting into the cooling system. Any good service center has a guage they install where the rad cap goes on to check ther amount of pressure you have.
Bernie
Bernie
Pro
Joined: Nov 2004
Posts: 607
Likes: 0
From: North Alabama
Originally Posted by BerniesVette
Put a pressure gauge on the radiator and see how much pressure you are building. It sounds like either the t-stat is not opening (remove it and see if that cures the problem) or you have a cracked head or blown head gasket; pressure from the engine is getting into the cooling system. Any good service center has a guage they install where the rad cap goes on to check ther amount of pressure you have.
Bernie
Bernie
Melting Slicks
Joined: Oct 2004
Posts: 2,662
Likes: 8
From: Knoxville Tennessee
The cap is designed to hold the pressure in the 12 to 15 PSI range. This raises the boiling point of the coolant. The pressure created inside a cylinder when the gas is ignited and blows the piston back down the cylinder is tremendous. The cap could never compensate for that. Have you installed a new cap to make sure it is working properly? Again, it sounds as if you are building tremendous pressure and the pressure cap and guage a shop has will tell you if you have a more serious problem. Another way to tell if you are getting pressure from the engine is to remove the cap and let the engine warm up. As the coolant starts to flow, it should flow smooth; if there is large amounts of bubbles appearing in the coolant you have a blown gasket or a cracked head or block. These are some the ways we troubleshoot larger engines where I work.
Bernie
Bernie
Melting Slicks
Joined: Oct 2004
Posts: 2,662
Likes: 8
From: Knoxville Tennessee
No bubbles is a good sign! I hope it is the cap. Don't buy a cheap one buy a good one and be safe. Again, if you can find a shop that has the pressure tester for the radiator and let them pressure check your rad.
Bernie
Bernie
Thread Starter
Intermediate
Joined: Jun 2004
Posts: 34
Likes: 0
From: Raleigh NC
well i went out and got a new rad cap rated 13 psi instead of 16. I ran the car hard today for while and there was pressure in the hose but not like before. So that looks alright. That was the good news...now the bad news...This morning the ups man showed up with my new headers, i couldn't wait, so i started pulling off the old ones. On the drivers side, when i took the header off, at the exit from the moter, and the entrance to the valve there was a lot of black crap, like burnt oil and stuff. Does this mean that I have a blown gasket or cracked head??? None of the other 7 exits in the motor had this crap. How can I figure out whats going on...?
Melting Slicks
Joined: Oct 2004
Posts: 2,662
Likes: 8
From: Knoxville Tennessee
Do you have a lot of white smoke from the exhaust. If coolant is going thru the cylinders it will cause a white vapor thru the exhaust. If it were me, I would pull the heads and intake to be safe.
Bernie
Bernie
Thread Starter
Intermediate
Joined: Jun 2004
Posts: 34
Likes: 0
From: Raleigh NC
No white smoke. When i cranked it without the headers on black smoke came from the same cylinder. Oil is getting down there, i just dont know how. If the seal rings around the valve are bad wont that let oil down in?
Burning Brakes
Joined: Aug 2005
Posts: 1,126
Likes: 0
From: Hudson Falls, N.Y. 76 Vette Modified L-48
Originally Posted by ngbrinkl
No white smoke. When i cranked it without the headers on black smoke came from the same cylinder. Oil is getting down there, i just dont know how. If the seal rings around the valve are bad wont that let oil down in?