over heating ford bronco

1976 ford bronco with 302 rebuilt .30 mild. put new high-flow aluminum water pump and new thermostat as well as a new 3 core radiator. yet it still keeps overhaeting. my timming is at 12 degrees.i have a new holley truck avenger 470 carb. this has been going on for a while with no luck.

When is it running hot? Driving in town or on the freeway? Is the oil clean? Is the fan shroud in place? Is the fan clutch good? Have you check the coolant level? Did you bleed the cooling system? Is the thermstat opening and closing when it should? Is the thermostat installed correctly?

it is running hot just sitting at idle also when running in city and highway.oil is new. fan shroud is in place and i have no clutch fan it is an automatic.as far as bleeding the cooling system i have opened the highest points as well as letting it get up to temp with radiator cap off.the thermostat is opening at 180 degrees and is installed correctly.had a friend double check my progress.

What kind of mixture antifreeze do you use?

I'd put in an electric fan on it, anyway. (It's worth looking into.)

Feel both the top and bottom radiator hoses are they hot. For some reason you are not getting circulation. Check the belt and pulley for the water pump. Will the heater work properly it may be air locked. Was the pulley size changed when you repaired the engine. Did you install new equipment and get the pump rotation backwards. The easiest way this could happen is to install a serpentine belt so the side which drives the water pump is on the wrong side of the water pump pulley. A simple mixup which can cause problems.

A simple mixup

Speaking of which, getting the thermo in backwards doesn't do anyone any good. Did that once? Say 'Aye'.


Aye.

thermastat is in correctly i do have an electric fan but no help. both hoses are getting hot and with the cap off it looks as to be circulating. also performed a pressure test and past with no leaks and held presuure.i am so lost on this its keeps me up at night. please keep up with the questions any little bit will help and yes my antifreeze is a 50/50 mixture.

Make sure you check rotation on your water pump as the impeller has to be rotating the correct way. You should be able to observe when the thermostat opens and see a good flow. You are at the point that I would pull the pump and check if the impeller is loose or slipping. If you go this far I would pull the thermostat and bottom hose and stick a hose in the top and check for good flow. The machine shops either heat up the block and burn all oil and sludge or use a hot vat. They may have left something in the block pieces of old gasket and ect. You could have a bad sending unit if the radiator cap never blowed.
Hopefully you used good hoses with a metal spring to prevent collapse. Especially the lower hose.

thanks for the tips will try tonight while eating candy. ive got good new hoses with the all important springs. ill try the water hose and see. someone else said that there could be combustion from the heads leaking into the water chambers? do you know if this is true? ive done a pressure test and held well. what are your thoughts?
thanks
trick or treat (i already have the trick)
alex

You said you have an electric fan, is it blowing air through the radiator in the correct direction? Is it turning on?

Whenever I had a leaking head gasket that was bad I put on the pressure gage while running. If you have a leak it will bounce the gage at the leaking cylinder.
What happens to a bottom hose without a spring is that it will collapse as if a vacuum is applied to the inside of the hose when the thermostat opens.

I think that I would check the radiator with a pressure tester to see what kind of pressure that thing it getting to. If you are getting exaust leaking through the head gasket, the pressure will go up pretty fast. Also how long does it take to overheat? If it's overheating fairly fast, It may be the head gasket. Exaust pouring into the cooling system will feel like a scorching heat really fast. Or as someone else has stated, you may have the wrong water pump and the impeller is turning the wrong way. Make sure the polarity of the fan is correct also, so that the fan would turn the right direction.
Hope this helps..

The only other thing I have found after all your work is on my first job as a helper in a man brought in a 1956 chevy that was overheating. The old car would sit and idle for an hour in the garage. Take it out for a test drive it would overheat. He had hit something and all air flow was shut off to the radiator. The old mechanic brought me a sledge hammer and said to make a big opening for airflow. The cars used heavier metal at that time. This fixed the problem. Running through the mud can plug the condenser stopping air flow. This would also block airflow to the radiator. I noticed you have a Bronco a lot of people use them in the mud. In certain areas bugs will also stop airflow at the condenser.

my electric fan works great it comes on at exactly 170 degrees and is pulling air through great. did not get to perform waterhose test yet kids were to exited last night. when at idle it gets to 180 at normal rate then just keeps on going. doesnt matter if im at idle or cruising around. i did spray out my radiator and held light behind it and every thing looks good. the water pump is going in the right direction and is showing some flow. i did a temp test on the hoses when temp hit 200 degrees and top hose was at 135 degrees and bottom hose was at 155 degrees. i know that is not right.should be other way around.i will try the temp test tonight before i pull the water pump to see how long it takes to get hot.ill have time kids are with grandma. wife wont be happy. but the truck comes first.
thanks for the suggestions
keep them comming. if going to get new water pump any suggestions? ive researched and i like the flow cooler. has high out pumt at idle. being a mud runner thats important.
hope every body gets fat off that candy like me.

I don't think your new pump is the problem. This is a dumb question but the new radiator or new pump didn't have plastic shipping plugs to keep out dirt and you didn't see it or forgot to remove them? The new hoses with spring didn't help.

What did you find it might help somebody else.