buddy
Active Member
I know that my peak operating temps lowered a significant amount with using a lower t-stat, but I cant explain it, must be impossible 
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Cooling Up Grade
- Thread starter dieselsmoken33
- Start date
- Staff
- #22
I know that my peak operating temps lowered a significant amount with using a lower t-stat, but I cant explain it, must be impossible
That's what I meant about your Camaro being different than a 6.5TD ... in your Camaro, the cooling system capacity is much greater than your engine's heat-generating capacity. Not so in these trucks... The cooling system capacity is not as high as the heat-generating ability of the engine when working hard.
For instance, taking the thermostat right out in your Camaro will let it run REALLY cool... but let's say you tried that in one of these trucks - first, it would run crappy (diesels don't like cold), but as soon as the engine started pulling and generating heat, the temp would climb back up again.
The only thing a 180* Tstat in a working 6.5 will help with is the time it takes to overheat... if you can get to the top of the hill and start down before the inevitable happens, then you are OK, and the 180* Tstat will give you maybe an extra 20-30 seconds to do that.
On long hills, you're still hooped.
If you want to replicate the scenario in your camaro, put a sheet of cardboard over the rad and try pulling something hard, uphill, with both thermostats, a 180* and a 195*.
You'll see what I mean.
- Staff
- #23
Thermostats are a VERY misunderstood part of a cooling system. Going to a 180 T-stat VS a 195 will do NOTHING to solve your engine from heating up to 230 on a long pull. All it will do is put a band-aid on the problem by giving you a little extra time before the coolant reaches 230. The temp rating on a T-stat is when it begins to open and it should reach fully open at roughly 12-15 degrees above it's rated temp. Diesel engines NEED to reach roughly 200-205 to reach peak efficiency. This also goes back to TD's thread about the ATT and intercooling. Your engine needs to atain roughly 190-195 to run efficiently.
To TRUELY lower engine temps you have to increase the amount of heat that the coolant in the system can absorb from the block and transfer to the incoming air through the radiator.
1.You need a water pump that can move the coolant through the block fast enough to not overheat before it exits, but yet slow enough for it to absorb the heat from the cylinder walls.
2.You need a thermostat that will let the engine stay at or above the minumum needed engine temp(roughly 185 for best efficiency).
3.A clean raditor inside and out that will allow the absorbed heat to be deposited through ALL of the surface area of the radiator.
4.A free flow of air through the radiator to absord the dissipated heat, and a fan clutch that will allow peak fan RPM's to maintain peak flow through the radiator at the optimum temperature, but yet not let it go above the upper end of that spectrum(roughly 210-212).
The temps I gave are for those of the IDI 6.5 as every engine has it's own sweet spot. There are MANY variables to a cooling system that need to be considered, and they all MUST work together to make the system work. If the above variables are met, then the cooling system is functioning properly.
To TRUELY lower engine temps you have to increase the amount of heat that the coolant in the system can absorb from the block and transfer to the incoming air through the radiator.
1.You need a water pump that can move the coolant through the block fast enough to not overheat before it exits, but yet slow enough for it to absorb the heat from the cylinder walls.
2.You need a thermostat that will let the engine stay at or above the minumum needed engine temp(roughly 185 for best efficiency).
3.A clean raditor inside and out that will allow the absorbed heat to be deposited through ALL of the surface area of the radiator.
4.A free flow of air through the radiator to absord the dissipated heat, and a fan clutch that will allow peak fan RPM's to maintain peak flow through the radiator at the optimum temperature, but yet not let it go above the upper end of that spectrum(roughly 210-212).
The temps I gave are for those of the IDI 6.5 as every engine has it's own sweet spot. There are MANY variables to a cooling system that need to be considered, and they all MUST work together to make the system work. If the above variables are met, then the cooling system is functioning properly.