radiator over flowing

[jh76cj5]

Hey, fellow cj gals and guys.I have a problem with my radiator overflowing. Let me start at the beginning. I replaced the water pump due to the bearing being worn out in the old one. I also took the thermostat neck housing off and resealed that also including a new gasket. In the process i replaced all of the hoses. I replaced the thermostat some time back it didn't look bad when i took it out when i had the neck off. Anyway after everything was put back together, i started the old 5 up. She ran great. In a short few minutes i noticed antifreeze leaking out of the little spout that is supposed to have a hose that goes to an overflow bottle ( it has neither ) I am leaning toward the thermostat, but it didn't seem to get hot enough for the thermostat to get to the temp where it should open. ( it doesn't have a temp gauge that works either.) it just ran a few short minutes maybe 5 at the most when it started puking out antifreeze. The radiator was not warm and the valve covers were barely getting warm. The motor is a AMC 304 . does anyone have any suggestions. i would appreciate any advice. Thank J.H.

 

[Torxhead]

You should have an overflow tank on that thing, another possibility could be a weak radiator cap. Air in the cooling system could be another problem, some guys bleed it out by loosening a hose while others just drive it up and down steep hills to get the air out to the top.

 

[jh76cj5]

Thanks for the info,I forgot to mention I put a new radiator cap on it. Its the kind that has the lever on top to relieve pressure. When i lifted it it really squirted antifreeze then. So do you think it might be air in the system?

 

[lutry]

What I had once was that the heat exchanger was clogged, the from
time to time squirting of antifreeze stopped, when I cleaned it with
citric acid until water could freely flow through it. Now there is
nothing any more...

 

[Hedgehog]

What you are experiencing is perfectly normal. I have been amazed at how much fluid the tank will hold. At any one time the tank could be filling or emptying depending on how hot the cooling system really is.

When my 360 was installed the Jeep got all new cooling components. It is almost impossible to find a stock overflow tank for a '75 so with room an issue a stainless steel tank for a hot rod was installed. The it actually is a thing of beauty. Polished Stainless Steel, ~1.75" in diameter and ~15 long, with cap, filler and overflow tube. The point is when the engine is hot the fluid level is at the almost at the top, when the engine is cold it's almost at the bottom about a 7" differance. This concerned me until hot and cold measurements were taken, it turned out that the fluxuation was consistent. Even with the drastic fluxuation fluid was not being lost in the system.

 

[billyballer]

Thanks for the info,I forgot to mention I put a new radiator cap on it. Its the kind that has the lever on top to relieve pressure. When i lifted it it really squirted antifreeze then. So do you think it might be air in the system?

Be sure you have the right cap, both in terms of pressure and depth. I would run it without the cap on to get it up to temperature and let it burp air and excess water out as well.

 

[Hedgehog]

Radiators build pressure when they are hot. Pop the cap on ANY hot motor and radiator fluid will come boiling out with considerable authority. It's a very good way to scald not only your hands, but your face.

 

[GatorBate]

I tucked a antifreeze jug under the battery between the fender and battery tray brace and ran a hose to the radiator for an overflow. Not a pretty as Hedgehog's stainless steel overflow but it seems to work.

Summit Racing has a great section of overflow tanks

 

[Torxhead]

I tucked a antifreeze jug under the battery between the fender and battery tray brace and ran a hose to the radiator for an overflow. Not a pretty as Hedgehog's stainless steel overflow but it seems to work.

Now that is the real Jeepers way.

 

[Hedgehog]

Believe me if I could have gotten a plastic one in the configuration needed I would have.

 

[paparooster]

? Did you burp the system to get all the air out of it ? there usually is an air pocket from draining the antifreeze out of the motor . you need to run motor up to temp and heater on with cap off to purge air out then fill radiator back up when the air is out of system .

 

[mstar]

Sounds like a simple case of letting the system normalize then top of with coolant just like PapaRooster recommended. Overflow bottle keeps the cats out of the anti-freeze.If your not going to run a overflow(wanting to keep original)just let the coolant find it's level and don't top off.Usually about a 1" below top of tank.The initial warmup can be pretty violent.If so just shut off after you think t-stat has opened and let cool down and then add coolant.I run coolant recovery system on my '69 and non on the '67 mike