Fan Clutch working?
06-05-2019, 11:35 AM
#16
Administrator
One other possibility I just thought of. Is your coolant level dropping at all? If it is, and since your truck is a 99, you may have the infamous 53 block.
The 53 block had the thin area on the right side of the block that is prone to stress cracks. The inside part of this area of the block is the water jacket. When it cracks you start looking coolant and you also have temperature issues.
More info here:
53 Block FAQ and Information
The 53 block had the thin area on the right side of the block that is prone to stress cracks. The inside part of this area of the block is the water jacket. When it cracks you start looking coolant and you also have temperature issues.
More info here:
53 Block FAQ and Information
06-05-2019, 07:21 PM
#17
Registered User
Thread Starter
Ohhh... sir.. I have read till my eye ***** are glazed over on the 53 block when I bought the truck 10+yrs ago. Initially, I thought, "ohhh no"
With the odometer @ 324k miles, I think I have a good one
I just need to figure out this coolant issue, never hear the "roar" of the fan clutch actually engaging. I'm still trying to confirm... does a fan clutch actually lock up?
Thank you for the input!
With the odometer @ 324k miles, I think I have a good one
I just need to figure out this coolant issue, never hear the "roar" of the fan clutch actually engaging. I'm still trying to confirm... does a fan clutch actually lock up?
Thank you for the input!
06-05-2019, 11:46 PM
#18
Administrator
It's gotta get hot (coolant temp) for the fan clutch to really engage/lock up tight and have the crankshaft drive the fan hard. I don't think it will lock up 100% due to it being a fluid coupling, and not a physical mechanism. This excerpt from the service manual should provide some better info:
If you want to hear the fan, slip a piece of cardboard in front of the radiator. Make sure the cardboard covers as much of the radiator as possible, if not the whole thing. Make sure to put it between the radiator and charge air cooler (intercooler). Then go for a drive, keep an eye on the coolant temp. Around 210° - 215º you should hear the fan engage and make a lot more noise. Pull the cardboard out when done.
I think you may be over thinking this. I rarely ever hear my fan engage. I really have to be working my engine hard (towing in the hills) before I hear it do it's job. Dodge put a really large radiator in our diesel trucks, almost overkill on the trucks used as daily drivers that rarely tow.
Originally Posted by Service Manual
A thermostatic bimetallic spring coil is located on the front face of the viscous fan drive unit (a typical viscous unit is shown in (Fig. 31). This spring coil reacts to the temperature of the radiator discharge air. It engages the viscous fan drive for higher fan speed if the air temperature from the radiator rises above a certain point. Until additional engine cooling is necessary, the fan will remain at a reduced rpm regardless of engine speed. Only when sufficient heat is present, will the viscous fan drive engage. This is when the air flowing through the radiator core causes a reaction to the bimetallic coil. It then increases fan speed to provide the necessary additional engine cooling. Once the engine has cooled, the radiator discharge temperature will drop. The bimetallic coil again reacts and the fan speed is reduced to the previous disengaged speed.
NOISE
NOTE: It is normal for fan noise to be louder (roaring) when:
NOISE
NOTE: It is normal for fan noise to be louder (roaring) when:
- The underhood temperature is above the engagement point for the viscous drive coupling. This may occur when ambient (outside air temperature) is very high.
- Engine loads and temperatures are high such as when towing a trailer.
- Cool silicone fluid within the fan drive unit is being redistributed back to its normal disengaged (warm) position. This can occur during the first 15 seconds to one minute after engine start-up on a cold engine.
I think you may be over thinking this. I rarely ever hear my fan engage. I really have to be working my engine hard (towing in the hills) before I hear it do it's job. Dodge put a really large radiator in our diesel trucks, almost overkill on the trucks used as daily drivers that rarely tow.
06-08-2019, 10:59 AM
#19
Registered User
Thread Starter
JRS... thank you for the details.
I checked antifreeze...not really dropping at all and has remained pretty much at the full level.
Check the radiator and it does have some junk, oily debris in front of it which I am going to clean off.
I also extended the breather vent hose to eliminate this oily build up.
Maybe just the small area of oily debris on the front of the radiator is not allowing it to cool as properly as it should....
Going to monitor things and go from here. Thank you for the replies!
I checked antifreeze...not really dropping at all and has remained pretty much at the full level.
Check the radiator and it does have some junk, oily debris in front of it which I am going to clean off.
I also extended the breather vent hose to eliminate this oily build up.
Maybe just the small area of oily debris on the front of the radiator is not allowing it to cool as properly as it should....
Going to monitor things and go from here. Thank you for the replies!
06-25-2019, 03:03 PM
#20
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Was directed to this thread because my 2016 4500 with the 6.7 is overheating. Replaced thermostat, water pump, fan clutch, flushed the system from each hose, each end, forward and backwards. Still, in traffic it will creep well above 215. Sometimes it wont do it for 4-5 hours, other times on the first run of the day. I'm not sure where to begin, but i never hear the fan go into that high gear or sound like a turbine or anything, even when it spikes up to 230-240+ and we have to shut it down. Sometimes over heats towing a car, othertimes could be empty. It's constantly doing it, inconsistent about when. Any opinions?
06-25-2019, 03:30 PM
#21
Registered User
Was directed to this thread because my 2016 4500 with the 6.7 is overheating. Replaced thermostat, water pump, fan clutch, flushed the system from each hose, each end, forward and backwards. Still, in traffic it will creep well above 215. Sometimes it wont do it for 4-5 hours, other times on the first run of the day. I'm not sure where to begin, but i never hear the fan go into that high gear or sound like a turbine or anything, even when it spikes up to 230-240+ and we have to shut it down. Sometimes over heats towing a car, othertimes could be empty. It's constantly doing it, inconsistent about when. Any opinions?
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