Water Temperatures

[mack1975]

On my 2001 CH612, with a 310/330 engine, I have a 180 degree thermostat. At idle, I warm the truck up and watch the thermostat open and close while the gauge reads 175 when it opens and it cycles between plus or minus 171-175. I take a heat sensor gun and shoot the water manifold and it reads about 185 at the manifold. I then run the truck to get it warm while sitting still and at 1600 RPM. Once the gauge reads 200 my Kysor fan comes on and quickly cools the engine down, as it should, then the truck seems to stay at around 190 degrees, plus or minus. I'm concerned that my readings aren't correct due to the fact that the gauge shows the thermostat cycling at 170-175 prior to trying to run the truck to force it to get warmer. When the gauge reads 200 I shot the manifold at it read 215. I have flushed the engine, put in a new thermostat, changed the water temperature sensor at the backend of the manifold, put in new coolant and it seems to be working fine. Runs like a top. This is my first newer style truck, as I am used to my old 675 motor, that I start up and if I just let it run at 800 RPM it gets up to 180 on the gauge and on its own it just stays there, at idle. Is this normal for this 2001 era etech engine to operate and I'm just not used to it having to run up to 200, if my gauge is correct, or does something sound wrong? If my gauge is reading low, showing the thermostat opening at 175 instead of 185, then is the fan really turning on at 200 or is it 210? Any ideas would be appreciated. I'm just trying to learn how this truck operates. Thank you.

[Rob]

On my 2001 CH612, with a 310/330 engine, I have a 180 degree thermostat. At idle, I warm the truck up and watch the thermostat open and close while the gauge reads 175 when it opens and it cycles between plus or minus 171-175. I take a heat sensor gun and shoot the water manifold and it reads about 185 at the manifold. I then run the truck to get it warm while sitting still and at 1600 RPM. Once the gauge reads 200 my Kysor fan comes on and quickly cools the engine down, as it should, then the truck seems to stay at around 190 degrees, plus or minus. I'm concerned that my readings aren't correct due to the fact that the gauge shows the thermostat cycling at 170-175 prior to trying to run the truck to force it to get warmer. When the gauge reads 200 I shot the manifold at it read 215. I have flushed the engine, put in a new thermostat, changed the water temperature sensor at the backend of the manifold, put in new coolant and it seems to be working fine. Runs like a top. This is my first newer style truck, as I am used to my old 675 motor, that I start up and if I just let it run at 800 RPM it gets up to 180 on the gauge and on its own it just stays there, at idle. Is this normal for this 2001 era etech engine to operate and I'm just not used to it having to run up to 200, if my gauge is correct, or does something sound wrong? If my gauge is reading low, showing the thermostat opening at 175 instead of 185, then is the fan really turning on at 200 or is it 210? Any ideas would be appreciated. I'm just trying to learn how this truck operates. Thank you.

Gauges, transducers, and transmitters used to drive gauges have a very wide tolerance they are allowed to operate within. They are not laboratory quality, or accuracy. Your readings with a temperature gun are most likely more accurate than the gauges supplied in the truck.

I don't think you have a big problem, nor are the equipments operating outside of design parameters as you do not mention any overheating. What I would be concerned with is if this is a change from prior experience. If it is, something needs addressed. Otherwise it is probably alright to run for a bit to evaluate once more information is gained.

Rob

[mack1975]

i have not run the truck on the road yet . just making sure all is ok. thanks

[Lmackattack]

just a thought but the block temp can be higher or lower than the water temp. the water is used to cool the engine and carry it away. Try aiming the temp gun at the radiator inlet and see what temp that is at. then shoot the radiator exit. I would suspect the head will always be hotter than the water is. Whats your oil temp? its normaly 10 deg less or the same as the water temp. these new engines are designed to use both the oil and water to help keep things cool and under control.

[Rob]

The best place to ascertain engine temperature is at the outlet of the engine coolant. Typically this is just below the thermostat itself. The cylinder heads absorb the most heat attributed to combustion of the fuel/air mix, and in most engines the heads are cooled last to keep from "thermal shock" cracking of the castings. Some cooling systems are reversed and not use ethylene glycol, but rather propylene glycol or another coolant.

Rob