Rebuilt slant 6 overheating

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Kevinmatt

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I had my slant six from my 67 dodge dart rebuilt , I had the original old radiator cleaned and roded out . After five minutes of running on idle, the temperature reads at 195°-210° degrees. What is the operating temperature for a slant six? is that considered a little too warm or overheating? I read that timing could actually cause overheating !? Help! I need advice .
 
make sure you don't have an air pocket in the coolant system....happened to me on a rebuilt 318

If it was rebuilt then the engine had to be bone dry so an air pocket might still be in the engine somewhere causing the overheat. Might run the engine without a radiator cap to purge the air.
 
make sure you don't have an air pocket in the coolant system....happened to me on a rebuilt 318

If it was rebuilt then the engine had to be bone dry so an air pocket might still be in the engine somewhere causing the overheat. Might run the engine without a radiator cap to purge the air.
Ok for sure I'll try that , thank you .
Do you know the average operating temperature for a Slant 6 ?
 
depends on what thermostat you install ...I always use a 195 thermostat and it stays on the low side of the temp gauge
 
When it starts to overheat, try running a garden hose on/through the radiator and see what temp it cools the engine down to... If it cools down a significant amount, you are either not getting enough airflow through the radiator or not enough water flow through the radiator may need a recore... (assuming that the engine side of the cooling system is good - water pump etc...) A recore does not recondition a radiator, it just cleans it out...

The engine temp should run where the thermostat is rated...

If it's a timing issue, try advancing the timing a bit and make sure that it doesn't spark knock/ping... Retarded timing may cause it to run hot...
 
After five minutes of running on idle, the temperature reads at 195°-210° degrees.

What does it read while driving down the road with air flowing past the radiator? This is a rebuilt engine and will likely run a little hotter until things settle in. I would drive it for 500 miles at varying speeds and rpm's and see where the temps are after you drain the break in oil out of it?
 
hi and hello:

did you ever solve your high operating temp in your slant-6??
You
What does it read while driving down the road with air flowing past the radiator? This is a rebuilt engine and will likely run a little hotter until things settle in. I would drive it for 500 miles at varying speeds and rpm's and see where the temps are after you drain the break in oil out of it?
I will drive it tomorrow morning and I get back at you with the temperature it's reading.
 
When it starts to overheat, try running a garden hose on/through the radiator and see what temp it cools the engine down to... If it cools down a significant amount, you are either not getting enough airflow through the radiator or not enough water flow through the radiator may need a recore... (assuming that the engine side of the cooling system is good - water pump etc...) A recore does not recondition a radiator, it just cleans it out...

The engine temp should run where the thermostat is rated...

If it's a timing issue, try advancing the timing a bit and make sure that it doesn't spark knock/ping... Retarded timing may cause it to run hot...
Thank you for the advice and I will let you know where it's reading tomorrow morning.
 
And here it is a month later and no response yet. Nice, real nice!

Sorry !!!
, So here it is
I ran my dart for a couple weeks now. I have been letting my radiator purge while running in idle . One big factor was the timing . To find out my time time chain is completely off . I had to modify my distributor to get the dart running fine . My distributor actually points at number six, so I'm tricking the motor on thinking it's fring on number one with the modification. So yes my motor's number 1 position is number 6 position .I bought a glow shift temperature gage and is now reading at 195° to 200 ° and that's runing the dart for 30 minutes on the street in 95° degree weather. Hell yeah!! Summer nights here I come !!! That's everyone !
 
You might want to take it back the shop that rebuilt the engine and have them fix their screw up. If the timing is really that far off. They have some explaining to do.
 
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