Weird Overheating Issue

dburkett8 · May 21, 2017

Hello

i have a 383 thats keeps overheating. Lets start from the beginning

I had a valve that needed to be lapped. I drained the coolant and removed both heads. Changed the head gaskets and the heads bolts and torqued everything down as per the manual. I also changed out the intake manifold and put on an new edelbrook 4bbl electric choke carb. I changed the engine oil and refilled the Coolant. I timed the engine to 2.5 degrees BTDC and set the idle RPM to around 700. The top hose out of the radiator gets extremely hot.

Everytime i start the engine, within 3 minutes my gauge shows the temp is above 220. I checked my Thermostat and its opening up when its supposed to, I changed the sender and same thing, i also checked my gauge and its good as well. I ran the engine with the radiator cap off and verified the system is purged of air, i used a compressor and blew air into the radiator through the overfill hose with the radiator cap on and the system held the pressure, i verified the radiator is full , i put a block tester on the radiator and with the engine on for 8 min the fluid remained blue indicating there is not a leak through the head gasket. The only thing i can think of is the pump.. anybody have any method of checking it without taking it out? or how to resolve this issue?

dane

Dennis H · May 21, 2017

Most here know more than me. Sounds like you are doing the right stuff. Shroud? Laser temp gun to be sure of correct reading. 3 minutes seems quick. Visible flow? Green coolant?

dburkett8 · May 21, 2017

Dennis H said:
Most here know more than me. Sounds like you are doing the right stuff. Shroud? Laser temp gun to be sure of correct reading. 3 minutes seems quick. Visible flow? Green coolant?

I have a laser gun coming tomorrow. The guage is showing that in 3 min. By the way its an aftermarket guage. But i checked it with some hot water and eveything work correctly. I put my hand on the rubber pipe but im a cant tell the difference between the vibration of the engine and the coolant flow. Whats the way you visually check? o and the shourd is good and the fan is spinning.

Dennis H · May 21, 2017

Look into the radiator with the cap off? I had a thermal fan clutch failure that was hard to diagnose. Spun it cold, then hot and could not tell the difference. Caused a temp spike at idle. Does it cool down when moving?

dburkett8 · May 21, 2017

Dennis H said:
Look into the radiator with the cap off? I had a thermal fan clutch failure that was hard to diagnose. Spun it cold, then hot and could not tell the difference. Caused a temp spike at idle. Does it cool down when moving?

Its up on jacks as i just finished putting it all back together. At idle the fan spins and the engine is getting airflow. Its just keeps overheating

Dennis H · May 21, 2017

Time for others to chime in. My fan turned too, just not fast enough at what was supposed to be full lock-up.

727 · May 21, 2017

Pump is easy to remove.

Ski 61701 · May 21, 2017

Try bumping your timing up some more.

gtxno1 · May 21, 2017

Thermostat upside down? head gaskets upside down?

Bruzilla · May 21, 2017

Are there any secondary signs of an overheat? Pinging? Dieseling? Smoke? Steam from the radiator cap?

Dennis H · May 21, 2017

When rebuilt, mine spiked on initial run.

dburkett8 · May 21, 2017

gtxno1 said:
Thermostat upside down? head gaskets upside down?

Thermostat is good and the head gaskets were the universal application from fellow pro. No up or down either way on is good

dburkett8 · May 21, 2017

Bruzilla said:
Are there any secondary signs of an overheat? Pinging? Dieseling? Smoke? Steam from the radiator cap?

If I let I sit for long enough it will start to ses smoke exit the valve cover which I belive I'd the coolant

dburkett8 · May 21, 2017

Dennis H said:
When rebuilt, mine spiked on initial run.

For hoe long?

Dennis H · May 21, 2017

dburkett8 said:
For hoe long?

Don't remember. Long enough to scare the crap out of me. I think the third run was normal. Let it set overnight after the second episode.

jimt1971rr · May 21, 2017

When you get you infrared reader, check the radiator in multiple places to check that the coolant is being cooled properly. I am thinking you might have a blockage in your core.

Photon440 · May 21, 2017

Could it be your head gaskets? Some, like P/N 3614824 have smaller coolant holes and have been thought to cause overheat problems.

mopar 3 B · May 21, 2017

dburkett8 said:
If I let I sit for long enough it will start to ses smoke exit the valve cover which I belive I'd the coolant

Smoke coming from the valve cover is not a good sign. Does it smell like burnt oil or is it steam and smell like coolant?
Check the oil and make sure it is not foaming or turning a yek gray color.
I am think a cracked or warped head.

Al Zangenberg · May 22, 2017

dburkett8, As GTX1 mentioned: "Thermostat upside down?" Have you visually checked to see that it is properly installed? If it is upside down, it will cause quick overheating (as you describe). You wrote: "Every time i start the engine, within 3 minutes my gauge shows the temp is above 220. I checked my Thermostat and its opening up when its supposed to, I changed the sender and same thing, i also checked my gauge and its good as well." Not faulting your description (nor anything else), how do you know it's opening? Remove it, and at room temp, place it in a pot of water, & heat up the water. Put a thermometer in, so you can check what temp it opens at...

Try a 160 degree thermostat. That in, and of itself, won't make the engine run cooler, but when the thermostat opens (at 160), the temp should decrease. at least showing it is functioning. The rest depends on all the other variables being normal.

A four-bolt easy removal, & R&R water pump. Buy a hi-flow water pump with better impeller blades...

If the engine turns over easy & readily, after reaching 220 - then your initial timing is way-too-far retarded. Advance the distributor, until the engine doesn't turn over as quickly as before...

You may have a collapsing radiator hose, or restricted radiator tubes...

You definitely have a non-normal overheating problem - with, or without a shroud. Don't use too much antifreeze, No more than 50/50, and even a bit less anti freeze. I had a new '65 383 Satellite, that had no shroud. Never ran hot in south Florida heat. I rebuilt the engine in 1969, (same steel fan, no shroud), and no overheating...ever!

Use a Brand Name radiator cap. (Not more than 13-15 psi).

Try temporarily removing the thermostat. if the engine doesn't run hot, install a name brand new 160 unit. Both radiator hoses should be near the same temp, when the thermostat opens...

Just my $0.02...
I wish you well!
AL

dburkett8 · May 22, 2017

gtxno1 said:
Thermostat upside down? head gaskets upside down?

Al Zangenberg said:
dburkett8, As GTX1 mentioned: "Thermostat upside down?" Have you visually checked to see that it is properly installed? If it is upside down, it will cause quick overheating (as you describe). You wrote: "Every time i start the engine, within 3 minutes my gauge shows the temp is above 220. I checked my Thermostat and its opening up when its supposed to, I changed the sender and same thing, i also checked my gauge and its good as well." Not faulting your description (nor anything else), how do you know it's opening? Remove it, and at room temp, place it in a pot of water, & heat up the water. Put a thermometer in, so you can check what temp it opens at...

Try a 160 degree thermostat. That in, and of itself, won't make the engine run cooler, but when the thermostat opens (at 160), the temp should decrease. at least showing it is functioning. The rest depends on all the other variables being normal.

A four-bolt easy removal, & R&R water pump. Buy a hi-flow water pump with better impeller blades...

If the engine turns over easy & readily, after reaching 220 - then your initial timing is way-too-far retarded. Advance the distributor, until the engine doesn't turn over as quickly as before...

You may have a collapsing radiator hose, or restricted radiator tubes...

You definitely have a non-normal overheating problem - with, or without a shroud. Don't use too much antifreeze, No more than 50/50, and even a bit less anti freeze. I had a new '65 383 Satellite, that had no shroud. Never ran hot in south Florida heat. I rebuilt the engine in 1969, (same steel fan, no shroud), and no overheating...ever!

Use a Brand Name radiator cap. (Not more than 13-15 psi).

Try temporarily removing the thermostat. if the engine doesn't run hot, install a name brand new 160 unit. Both radiator hoses should be near the same temp, when the thermostat opens...

Just my $0.02...
I wish you well!
AL

I appreciate it. I already took out the thermostat and put in hot water. It worked. So i am going to remove the pump and see how it looks. Thanks for the input

Weird Overheating Issue

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