Gearing down on hills 2 keep temp down

Lugging the engine generates more heat, if you have an EGT gauge you will see the exhaust temperatures rise like crazy running it floored in a gear that is too high while trying to maintain speed. The engine is working less if you drop a gear or two and let the transmission do the work albeit at a slower ground speed. Airflow across the radiator does slow with a drop in speed, but you should be OK, a diesel engine actually cools off at idle, this is why I always idle until my EGT drops below 300°F before shutting down, in other words I don't climb a long grade and then shut off with the engine heat soaked at the top.

An EGT readout also shows how much relative energy is required running into a headwind or increasing speed, I don't know if it is still true on the EGR engines, BUT way back when Mr. Cummins discovered best fuel economy running around 600°F (might of been 650°F) on some of his early diesel trials, so if you normally run those temperatures at say 62 MPH and then you see a 200°F increase to maintain the same speed you are either running into the wind or pulling a grade or both, by the same token if running on the flat with no headwind you can see what happens when road speed increases, the EGT goes up, thus indicating more energy used, more heat generated out the exhaust, etc.

TS

 

Your engine does not have to work as hard when you drop a gear. That's why we have gears.
High RPMs do not necessarily mean high temps.
Also, higher RPMs increase fan speed. The vehicle speed does not influence the amount of air passing through the rad as much as fan speed does.
Drop a gear or two. It will not make your trip all that much longer and might give your engine a break.

Having said that; I am wondering why your engine is behaving differently from previously. If the same conditions are producing different results perhaps you need to investigate other options. It may not be your rad that needs upgrading. I think you should describe your symptoms to a skilled mechanic and see if they can troubleshoot for you.

 

wait till summer kicks in. you won't be going full bore then. and if you do. you can probably kiss your job good bye if your truck doesn't have a shutdown. you'll burn up the motor.

good idea to just flip the switch and keep her on up the hill. and down the hil to so it cools down faster.

and if your running your air conditioner. that's that much more heat going through the radiator. which means you'll either be going SLOWER. or shutting off the a/c till you've hit the top.

 

When you can climb the grade without pegging the boost you'll know you've dropped enoughgears.

 

It sounds like you have cooling problems. I would get it ready for summer.

Is the radiator clean?
Is there scale build up on the inside? A dirty block/radiator will reduce the transfer of heat. A flush might be needed.
The thermostat might be wore.
Is the fan clutch performing properly?

 

Like the others have said, dropping gears reduces the load on the engine. Also when you increase RPM you increase the air flow through the engine. The more air you can move through the engine, the more heat will be expelled through the exhaust. Your air to air needs to be checked for leaks if it hasn't been already.

 

I had a bird nest between condensor and radiator and would only heat up on long hills like the one on 68 in Md.
Think the birds built nest while I was on a 6 week vacation in 10.

 

Did you at least get some cooked eggs?

TS