340 coolant trouble

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67ragtop

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I fired up my motor tonight and ran into some trouble. Any help would be appreciated. The motor has been completely rebuilt at a local shop. Ran fine at the shop for long periods of time. Brought motor home installed it and now the problems start. Does not seem like the coolant is circulating at all. I removed the thermostat. Heater core hoses are hot. Radiator cap removed. Top radiator hose is hot. Lower radiator hose is cold. Fluid seems to be moving slow in radiator. I am thinking propellar busted or new water pump shot? Any ideas????
 
What temp is it running? If the top hose is hot and the bottom is cold that's normal. The top hose can't get hot unless the coolant is circulating. The top hose is the inlet to the radiator from the engine so naturally it's the hotter running hose. The bottom hose is the outlet to the engine so it's coolant that's ran through the radiator which has been cooled.

The coolant moves slow through the radiator on my Cuda also but it never even somes close to overheating.
 
No guages so far. Sorry, it took me so long to reply. Blew the top hose but it was old. Put a new hose on and it overheated and bubbled up through the uncapped radiator. Pulled the new thermostat and put another new one in just in case. Still bubbled up through the uncapped radiator. Pulled the thermostat to see if the radiator would show some flow. Burned the coating off my brand new 700.00 dollar tti headers.
 
67ragtop said:
No guages so far. Sorry, it took me so long to reply. Blew the top hose but it was old. Put a new hose on and it overheated and bubbled up through the uncapped radiator. Pulled the new thermostat and put another new one in just in case. Still bubbled up through the uncapped radiator. Pulled the thermostat to see if the radiator would show some flow. Burned the coating off my brand new 700.00 dollar tti headers.
Click to expand...

Bummer. Good thing it didn't get you. That could have been real bad. When their hot it'll puke it out like that when you pop the cap. You need to try to run it with the cap off and get all the air out of the system and see how it does. It won't build up pressure like that with the cap off either. Unless something is really bad wrong with it.

Do you have a coolant system pressure tester or know someone that has one you can borrow? If you get one you can pressurize the system cold and see if it's bleeding down internally. That would indicate a cracked block, head or blown/leaky head gasket. If it pressurizes OK you probably just have a stubborn air pocket in it you need to get bled out.
 
Before you do much more with it.

Tell us about the cooling system, has the radiator been recored, how big is it, are you using a shroud, clutch fan ? what is the initial timing, how hot is it getting, take a thermometer and stick it in the radiator to get a measurement. You mentioned your upper hose blew apart. Does the lower hose get collapsed, is it an old hose as well ? Is the lower hose new with a spring inside it ? What kind of water pump did you put on it, is this an AC car ?

Let us know, we can guide you better that way.
 
If you burned the coating off the headers, that tells me you are running LEAN. Lean is HOT. I would richen the mixture, and your water and engine temps will go down.
The bubbles are air bubbles, and needs to happen. The bubbles are also a result of boiling, in the heads, probably near the exhaust valves. This is common, and once the majority of the air is out of the system, and the rad cap is on, the bubbling will be stopped by the pressure of the system.
 
I'm not entirely sure about compatibility between the old engines and the newer stuff (bolt holes, etc.) but I'm wondering if the pump is a reverse rotation piece for a serpentine drive setup. I've seen it happen as a result of parts store clerks grabbing the wrong part. It makes a person crazy. However, this wouldn't explain how it didn't kick into 'puke coolant' mode in the shop.

As someone else mentioned, a massive air pocket will wreak havoc. Years ago, I had a 455 Trans Am that was notorious for air pockets after a cooling system drain. I eventually tired of this and whipped up a MacGyver-looking vacuum bottle contraption that did a nice job of pulling the air out of the system. Much torment was avoided from then on.
 
yeah, im willing to bet its air in the system....they make a little funnel that will seal ontop of your radiator where your cap would go.....fill your system up and let it run...make sure the heat is off....and wait till their are no bubbles left...be sure to watch the coolant level.....while burping the system it can fill that funnel up and overflow...
 
Is the radiator a stock unit placed in the stock location? Would the elevation of the inlet of the radiator vs the outlet on the motor be relative. You said the coolant was moving? We're thinking.........
 
Thanks for everyone's help. I think my problem is that I do not get to work on my car as much as I like(with work) and forget where I left off sometimes. The temps just got in to the 40's where I live and once again will have some time to work on the car. I flushed the coolant, retightened the belts, adjusted the timing and replaced the top hose. Ran the motor, let it burp (still no guages) I am still working on that problem. Finally, it started to circulate and did not overheat. I have been working on this car on and off since 1988 my junior year in highschool. Between college, military and crappy jobs I finally am at a place in my life where I can afford to give the car what it needs. When I get burned out at the lack of progress I stop and work on other things around the house. You guys keep me going from time to time and it is getting close. I am not on the site nor reply to it as much as I would like but one thing is for certain I will never sell my car! I will try to get some pics on the site soon. Thanks again!!
 
i've been working on my car since i could hold a wrench my older bro bought it when i was about 3 and spent countless hours helping with all those tight spaces, i think i was the only 5 year old who could do spark plugs faster that an adult, but anyways great story, i love hearing about long time resto's and car history, good luck on the build, cant wait to see pics:read2:
 
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