boiling over???
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boiling over???
i dont use this forum much because my truck never really gives me any problems. but one has come up and im hoping someone can help me out.
i have a 1978 f-250 with a 460 and auto. recently the radiator has been boiling over, the temp gauge shows normal though. i installed a new thermostat first (cheapest and easiest thing to do) when i lifted out the old one it was as if i opened a can of soda. large rush of air in the engine. i filled up the rad and let the truck idle of awhile, this is usually all it takes to get it to start boiling over. well it was fine. i put the rad. cap on and let it run longer and it boiled over. i took the cap off, filled it back up and let her run quite awhile. no boiling over with cap off. i shut off the truck and it burped out a large gush of water. (no cap). im not a mechanic, just a basics kind of guy. can any of you guys give me some ideas here?
thanks, CG
i have a 1978 f-250 with a 460 and auto. recently the radiator has been boiling over, the temp gauge shows normal though. i installed a new thermostat first (cheapest and easiest thing to do) when i lifted out the old one it was as if i opened a can of soda. large rush of air in the engine. i filled up the rad and let the truck idle of awhile, this is usually all it takes to get it to start boiling over. well it was fine. i put the rad. cap on and let it run longer and it boiled over. i took the cap off, filled it back up and let her run quite awhile. no boiling over with cap off. i shut off the truck and it burped out a large gush of water. (no cap). im not a mechanic, just a basics kind of guy. can any of you guys give me some ideas here?
thanks, CG
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Between an air lock & people putting TOO MUCH coolant in the rad this can happen,.
The level of the coolant should be about 1" lower than the Rad Cap Lower Rim.
Filled any higher than that, coolant will come blowing out.
The level of the coolant should be about 1" lower than the Rad Cap Lower Rim.
Filled any higher than that, coolant will come blowing out.
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i had forgotten about that hole in the thermostat trick. im not sure how it would have gotten air locked in the first place though. someone told me it may be sucking air through a bad head gasket which would be a bummer. this truck is no beauty queen, she is my work horse do everything rig. i dont know if i can justify putting alot of cash into the engine. well thanks for the info guys its much appreciated.
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Sounds more like a bad head gasket, -sorry. Good thermostats usually have a small air bleed hole usually with a jiggle pin in it. I often remove the pin tho and let a tiny amount of water circulate. Compression and firing pressure actually pushes gases past a bad head gasket into the cooling system. It can build pressure rapidly in the system if it is closed up.
Last edited by Torque1st; Mar 5, 2006 at 09:33 PM.
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I wouldn't be so quick to condemn the head gasket, it's real easy to get them airlocked. It's also possible the water pump crapped out also and isn't pumping any water.
IF the waterpump is NG you'd have very poor or no heat in the heater, so make sure the heat is working good. An airlock can also keep it from giving heat, so poke a hole in the t-stat and try again.
What I generally do on a stubborn truck is warm it up at idle until it's hot, then cap it and shut it off, let it cool a bit and open it up, if it's low on fluid fill it back up and do it again. You may have to do that 2 or 3 times until it stays full.
IF the waterpump is NG you'd have very poor or no heat in the heater, so make sure the heat is working good. An airlock can also keep it from giving heat, so poke a hole in the t-stat and try again.
What I generally do on a stubborn truck is warm it up at idle until it's hot, then cap it and shut it off, let it cool a bit and open it up, if it's low on fluid fill it back up and do it again. You may have to do that 2 or 3 times until it stays full.
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People talk about these "air locks" but I have literally done thousands of coolant changes on older vehicles like these back in the late 60's thru 70's and have never once had an "air lock" problem.
Maybe I am just super super super lucky tho, -NOT a chance. I have changed hundreds of water pumps and only one of those was for an impeller that had come loose and did not pump. The only way the coolant will not circulate is if the radiator or cooling passages are plugged up with scale.
Maybe I am just super super super lucky tho, -NOT a chance. I have changed hundreds of water pumps and only one of those was for an impeller that had come loose and did not pump. The only way the coolant will not circulate is if the radiator or cooling passages are plugged up with scale.
Last edited by Torque1st; Mar 6, 2006 at 01:01 PM.
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Originally Posted by Torque1st
People talk about these "air locks" but I have literally done thousands of coolant changes on older vehicles like these back in the late 60's thru 70's and have never once had an "air lock" problem. Maybe I am just super super super lucky tho, -NOT a chance. I have changed hundreds of water pumps and only one of those was for an impeller that had come loose and did not pump. The only way the coolant will not circulate is if the radiator or cooling passages are plugged up with scale.
Maybe I am just super super super lucky tho, -NOT a chance. I have changed hundreds of water pumps and only one of those was for an impeller that had come loose and did not pump. The only way the coolant will not circulate is if the radiator or cooling passages are plugged up with scale.
and I've seen quite a few that wouldn't burp, and I've had water pumps with rotted off impellers as well as impellers that spun on the shafts. Also seen a lot of t-stats put in upside down that cause the same problem or leaves jambed between the rad and condenser blocking the air flow.I just can't see condemning a head gasket without checking out the easy stuff first. I've always hated spending money
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Eric, I have to concur with Eric on this one 
I too have seen my share of engine cooling systems that WON't Burp properly.
My Buick 403 for instance.
It took 2 days to get all the air out of the cooling system after the coolant was drained to R & R a water pump.
Therefore, IMO, I have to rule out a Head Gasket until all the other possibilites have been used up.
Most head gasket problems I have seen show LOTS of Bubbling at the Rad Cap hole.
I too have seen my share of engine cooling systems that WON't Burp properly.
My Buick 403 for instance.
It took 2 days to get all the air out of the cooling system after the coolant was drained to R & R a water pump.
Therefore, IMO, I have to rule out a Head Gasket until all the other possibilites have been used up.
Most head gasket problems I have seen show LOTS of Bubbling at the Rad Cap hole.
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Originally Posted by yield2s
The engine temp is NORMAL guys. Just change the radiator cap and let me know what I win
mark
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Originally Posted by C G
lol, i had to reread my post to make sure i didnt make any promises. ok lets see, the heater fan barely works but the cab does warm up so im assuming (yes i know, never assume) the water is circulating fine. the thermostat is installed correctly. the over flow tube and bottle are long gone so i will get one from an auto parts store and replace, along with a rad cap and take it from there using some of the ideas ive read so far. if i have to replace head gaskets im afraid it will be time to retire this old truck. =(
mark
mark
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Quote : the over flow tube and bottle are long gone so i will get one from an auto parts store and replace,
~~~~~~~~~~~~~~~~~
No such thing on these trucks.
You have to add your own and make sure you get the correct cap after you do
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No such thing on these trucks.
You have to add your own and make sure you get the correct cap after you do