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Hello,

I posted earlier this week about my coolant puking out the overflow bag and all over my engine compartment and that's with the temp needle on 1/2, so I was wondering about exhaust gasses getting into the cooling system. Someone said to check the thermostat first so I did.

I did the test today, I drained the coolant and poured hot water into the top rad hose and angled it down and the water all poured out the bottom after a few seconds. So I know the thermostst is working fine.

What is the next move? With everything else eliminated how do I check for a blown head gasket and what are the signes of a blown head gasket.

Thanks, Greg.
 

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A blown head gasket would have coolant in the oil and oil in the coolant systems. Lot's of white smoke out the tailpipe when running, and in my experience the inability to cool the engine at all. My temp guage was pegged.
 

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Best thing to do now is to pull the spark plugs.....inspect them for proper operation residue color.

ALSO very important, check timing and check for vacuum leaks at the carb base or where the intake mounting surfaces meet the heads. False
lean conditions will also make your engine run hotter than normal.

if all else is well, then check your radiator, does it have a fan shroud? Is the radiator flowing well? How old is it? As time passes, we use tap water an the sediments in the tap water accumulate via electrolysis and create flow obstructions, thus affecting cooling capacity. I'd look into an aluminum radiator....(this fixed it for my Bronco)

Good advice on the head gasket but.....sometimes, when installing the heads, the gasket coolant passages won't line up so it is an important detail to ponder....

good luck and let us know what you find
 

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with the temp needle on 1/2
Assuming your temp gauge is accurate, you're NOT overheating. I suspect you're filling the radiator as full as you can, and the car is "puking" the excess coolant until it reaches a 'comfortable' coolant level for your car.

This is normal . . . if I fill my Mustang radiator to the top, it pukes out until the coolant level goes down to the top of the rows (about an inch from the top).

When the car is cold, open the radiator cap and drain about 1" of coolant until you can just see the top of the rows. Try running your car, watch the temp. gauge, and I'll bet it stops overflowing.

Just my $0.02, and I hope I'm right.

Rick
 

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quote from Rick: When the car is cold, open the radiator cap and drain about 1" of coolant until you can just see the top of the rows. Try running your car, watch the temp. gauge, and I'll bet it stops overflowing.

Just my $0.02, and I hope I'm right.

I'd try this too! One inch bellow the neck of the radiator will do the trick.
Of course my last trick was to put the thermostat in backwards.... ::Yep i got the Jackass award for the day.
 
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my previous 289 had this problem. I changed the head gaskets to no effect.Tried everything else too. The new owner has put a 4 row rad on and it runs great now. nice and cool.

cheers
shaun
 

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I did the test today, I drained the coolant and poured hot water into the top rad hose and angled it down and the water all poured out the bottom after a few seconds. So I know the thermostst is working fine.
Pouring hot water on the TOP of the thermostat shouldn't open it in a few seconds. Sounds like you may have it in upside down. Have never tried this particular method, so am not sure. The heat spring on the thermostat should be facing the engine. Another way to check the stat is to just start it up cold with the cap off the radiator. Observe it, and when the engine warms up, you should see a flow of fluid across the top of the radiator.

I posted earlier this week about my coolant puking out the overflow bag and all over my engine compartment and that's with the temp needle on 1/2...
With the gauge at 1/2, your engine is not running hot. A head gasket should blow enough coolant out that it won't have enough left to cool the engine. If you doubt the gauge reading, check with another one.

Entirely possible that the others suggestions about the radiator being overfilled is right on. Your radiator will never be full after cooling off. Each time it heats up, the coolant expands and forces unnecesary fluid out the overflow under the cap. So, when warm, the radiator is full to the top. When it cools off, the fluid contracts. So, when you check the fluid level when cool, it will be just above the radiator cores, or approximately 1" down in the tank. If you fill it at this point, it will just puke it out the next time you run it. When you park it, the residual heat from the engine will force more fluid out after shutting the engine off, before the fluid cools and contracts.

Hope this all makes sense. Good Luck.
 

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Here is the easiest way to test for a blown head gasket .

Fill your cooling system up so it's (as said above) below the neck of the radiator cap port . Fire the engine up with the cap off and watch it run . When the thermostat opens you will see water flowing around the top of the radiator at a good speed . If no water is flowing around the top of the radiator , stop the test here and replace the thermostat . Once the stat is replaced , do the above instructions again and retest for flow . If the coolant is not flowing at this time , stop and replace the water pump . If it is flowing then wait for the engine to "burp" if it's been refilled with coolant (if drained or very low) . If no burp is needed , and the engine has arrived at hot ( coolant flowing through radiator and gauge showing normal temps) replace the radiator cap .
Now take your vent hose from the radiator cap and slip it off the bag (if it won't come off the bag get a piece of tube from the store or apre stuff ) . Take the open end of the tube , other end attached to the radiator still , and place it in a glass of water . The water can be cool tap water too .
Now wait a minute and watch for bubbles . If the engine overheats during this there will be bubbles too , but if it is running normal temp and is warmed up there bubbles should be very little to none flowing from the vent tube . If it has a steady stream of bubbles blowingout the line then you could have a blown gasket or crack in something .
Also remember your radiator cap itself can be bad . If the cap is bad it will allow the coolant to boil at a lower temp and shoot right out of the engine . So replacing the cap might be a good option also . The cap should be replaced with the same rating as factory (or what your old cap is) . Replacing the cap with a higher pound cap will result in ruptured radiators/hoses/heater cores .
Most times if a engine has lost a head gasket the heater hoses and bypass hoses suffer failures for no reason . Good luck .
 
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