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Need help diagnosing why my 351c is running hot. It does alright cruising on flat but going up a long hill i will see temps over 210. The engine is a fresh rebuild with a RV cam and edelbrock 1406 carb. Confirmed thermostat opens and just installed a champion aluminum radiator with 2 big electric fans. I have tried 6,8,10 and 12 deg advance timing. Any ideas would be greatly appreciated!
I use a flushing "T" into a heater hose .
it has a cap that you unscrew , and fill the radiator, until coolant comes out of the t with no air . Then replace the cap and start the engine .
Fill the overflow to the max cold line as well.
First off, is it actually a Cleveland that was swapped in? If not then it's likely an M engine and not a C engine.
What is the rating on the thermostat?
What gauge are you using to determine temps?
Originally Posted by Davidmartin
It does alright cruising on flat but going up a long hill i will see temps over 210.
Nothing to worry about, unless it keeps creeping up. That 210 is actually a normal operating temperature for a modern engine. Your C or M might actually like 190-200 degrees. Though I agree that if running for example a 180 thermostat, you should reasonably expect the engine to stay near that temp.
Originally Posted by Davidmartin
The engine is a fresh rebuild with a RV cam and edelbrock 1406 carb.
What exact cam is in there. The RV description covers a wide range. Got specs, or maybe a cam card you can share the numbers from?
A fresh rebuild might run a tiny bit hot in the beginning anyway, but not for too long after it's started to break-in.
Was it bored? If so, how much over is it? The more you go, the more an engine tends to run hotter. Depends on the individual engine though. Were the cylinder walls sonic checked before boring?
Originally Posted by Davidmartin
Confirmed thermostat opens and just installed a champion aluminum radiator with 2 big electric fans. I have tried 6,8,10 and 12 deg advance timing.
What is the rating on the t-stat?
Good to advance the timing. Try some even more advanced just to see how it runs. Might not like more than 12, but it's worth a quick experiment.
The radiator is probably fine, but not sure about the electric fans at highway speeds or high loads. What size fans are they exactly. What CFM rating at how many inches of water (if the manufacturer gives that spec)?
Is the truck lifted? Bigger tires too? If so then aerodynamics might be coming into play.
At speed a higher truck has more high-pressure air build up underneath, which blocks some of the air trying to get through the radiator. Sometimes electric fans are just not up to the task. But having duals is a bonus unless they're just too small.
I use a flushing "T" into a heater hose .
it has a cap that you unscrew , and fill the radiator, until coolant comes out of the t with no air . Then replace the cap and start the engine .
Fill the overflow to the max cold line as well.
Are you running a correct 351C style Thermostat and was the coolant by-pass restrictor-plate replaced after the rebuild?
No kidding, the restrictor plate is critical. There is also no parts store thermostats that function correctly. The correct thermostat and the original style can be found here https://www.flowkoolerwaterpumps.com...brass-bypass-1
First off, is it actually a Cleveland that was swapped in? If not then it's likely an M engine and not a C engine.
What is the rating on the thermostat?
What gauge are you using to determine temps?
Nothing to worry about, unless it keeps creeping up. That 210 is actually a normal operating temperature for a modern engine. Your C or M might actually like 190-200 degrees. Though I agree that if running for example a 180 thermostat, you should reasonably expect the engine to stay near that temp.
What exact cam is in there. The RV description covers a wide range. Got specs, or maybe a cam card you can share the numbers from?
A fresh rebuild might run a tiny bit hot in the beginning anyway, but not for too long after it's started to break-in.
Was it bored? If so, how much over is it? The more you go, the more an engine tends to run hotter. Depends on the individual engine though. Were the cylinder walls sonic checked before boring?
What is the rating on the t-stat?
Good to advance the timing. Try some even more advanced just to see how it runs. Might not like more than 12, but it's worth a quick experiment.
The radiator is probably fine, but not sure about the electric fans at highway speeds or high loads. What size fans are they exactly. What CFM rating at how many inches of water (if the manufacturer gives that spec)?
Is the truck lifted? Bigger tires too? If so then aerodynamics might be coming into play.
At speed a higher truck has more high-pressure air build up underneath, which blocks some of the air trying to get through the radiator. Sometimes electric fans are just not up to the task. But having duals is a bonus unless they're just too small.
Good luck.
Paul
I swapped the motor. I do belive it to be the clevland not the Windsor or m. Im using an autometer sport comp gauge and a thermal temp gun. The temp does creep above 210 mostly when im going up a dirt trail slow or on the throttle alot. I'll post the cam specs and rebuild data tonight. T stat is 180 deg. I can try more advance, but thought it made it run hotter? The fans are 12" and move approx 1500cfm each. The truck is lifted with 35" tires but doesn't have much heat issue when cruising at speed, mostly at slow speeds. Thank you for the help!!!
No kidding, the restrictor plate is critical. There is also no parts store thermostats that function correctly. The correct thermostat and the original style can be found here https://www.flowkoolerwaterpumps.com...brass-bypass-1
No kidding, the restrictor plate is critical. There is also no parts store thermostats that function correctly. The correct thermostat and the original style can be found here https://www.flowkoolerwaterpumps.com...brass-bypass-1
Not true at all. The late 4.0L SOHC uses the same style stat and interchanges.
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