Noise - maybe fan? Cooling system health help
#1
06-01-2015, 10:55 AM
Join Date: Apr 2015
Location: Reno, NV
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Noise - maybe fan? Cooling system health help
Guys,
This is my first diesel as well as my first ex so I'm looking for a little help. It has started getting warm here and it seems like perhaps my cooling fan is engaging, even on the highway. I'm not sure it is the fan so I'll describe what I've got.
The noise - sounds like a medium pitch 'droning' noise. With constant throttle input it alternates between two slightly different pitches as if the RPM is increasing slightly and then going back down after 10 or 15 seconds, then repeats. If it were 'steady' I would think it was the cooling fan but it changes speed/pitch so I'm not sure.
The conditions - Most often after pulling a long steady grade, outside temps in the low 80s. AC running, speed around 70MPH +/- 5. Truck is unloaded - just myself and the family and our normal 'stuff', maybe 800Lbs, max.
Diagnostics - I have a Bluetooth scanner and my phone reports Oil temps around 210 when I hear the noise. I don't have coolant temps - not sure its available on the 7.3. Dash gauges all look normal - nothing out of the ordinary. Coolant and trans temp gauges are just slightly below center, which is what I've come to expect over the few weeks I've owned the truck. When the noise occurs if I shift to neutral and coast the noise disappears. With the truck in neutral if I 'Rev' the motor back up to 2k RPM where it was the noise returns - seems linked to motor speed. As soon as the truck is back in gear the noise returns (even when coasting down hill).
What I'm concerned about is the variation in pitch, does the fan clutch engage in 'stages' that could explain this?
I'm also concerned that I'm reaching 200+ temps on the highway on a warm day, no vehicle I've ever owned would engage the cooling fan on the highway, there is plenty of wind available. What kinds of temps to you guys see unloaded on they highway, what should I look at first if this isn't normal?
This is my first diesel as well as my first ex so I'm looking for a little help. It has started getting warm here and it seems like perhaps my cooling fan is engaging, even on the highway. I'm not sure it is the fan so I'll describe what I've got.
The noise - sounds like a medium pitch 'droning' noise. With constant throttle input it alternates between two slightly different pitches as if the RPM is increasing slightly and then going back down after 10 or 15 seconds, then repeats. If it were 'steady' I would think it was the cooling fan but it changes speed/pitch so I'm not sure.
The conditions - Most often after pulling a long steady grade, outside temps in the low 80s. AC running, speed around 70MPH +/- 5. Truck is unloaded - just myself and the family and our normal 'stuff', maybe 800Lbs, max.
Diagnostics - I have a Bluetooth scanner and my phone reports Oil temps around 210 when I hear the noise. I don't have coolant temps - not sure its available on the 7.3. Dash gauges all look normal - nothing out of the ordinary. Coolant and trans temp gauges are just slightly below center, which is what I've come to expect over the few weeks I've owned the truck. When the noise occurs if I shift to neutral and coast the noise disappears. With the truck in neutral if I 'Rev' the motor back up to 2k RPM where it was the noise returns - seems linked to motor speed. As soon as the truck is back in gear the noise returns (even when coasting down hill).
What I'm concerned about is the variation in pitch, does the fan clutch engage in 'stages' that could explain this?
I'm also concerned that I'm reaching 200+ temps on the highway on a warm day, no vehicle I've ever owned would engage the cooling fan on the highway, there is plenty of wind available. What kinds of temps to you guys see unloaded on they highway, what should I look at first if this isn't normal?
#2
06-01-2015, 02:12 PM
7.3 doesn't report water temp through the OBDII, so you won't be finding that. The gauge on the dash is supposedly using some algorithm to calculate water temp based off oil temp IIRC. There's no trans temp gauge in the stock cluster (nor the OBD port) either, not sure which one you're looking at...
200-220° for oil temperature is normal, depending on OAT and how hard you're running. When I beat on my rig (which is HARD beating), I see 219-220° max. Normal driving is down around 208-212°, which is normal operating temp for oil in a variety of vehicles - not just our PSD's.
Not certain whether the clutch locks to solid state or if it has varying degrees, I THINK it has some slippage until the internal fluid and clutch reaches the lock temperature. If the temperature is achieved, the fan will engage regardless of freeway speed or not since its a mechanical fan driven off the water pump.
I get a drone with the AC on around town, but it's steady when under fixed throttle and varies evenly with engine speed, as it should since it's a mechanical fan. I can't even hear it over 50mph, however I've got exhaust and mud tread tires so there's more ambient noise than you have most likely.
Side note, add your location and your vehicle specs in your signature. Makes things easier for everybody
200-220° for oil temperature is normal, depending on OAT and how hard you're running. When I beat on my rig (which is HARD beating), I see 219-220° max. Normal driving is down around 208-212°, which is normal operating temp for oil in a variety of vehicles - not just our PSD's.
Not certain whether the clutch locks to solid state or if it has varying degrees, I THINK it has some slippage until the internal fluid and clutch reaches the lock temperature. If the temperature is achieved, the fan will engage regardless of freeway speed or not since its a mechanical fan driven off the water pump.
I get a drone with the AC on around town, but it's steady when under fixed throttle and varies evenly with engine speed, as it should since it's a mechanical fan. I can't even hear it over 50mph, however I've got exhaust and mud tread tires so there's more ambient noise than you have most likely.
Side note, add your location and your vehicle specs in your signature. Makes things easier for everybody
#3
06-01-2015, 03:03 PM
Elder User
#4
06-01-2015, 03:18 PM
Join Date: Apr 2015
Location: Reno, NV
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I have an '02, 7.3 4x4 limited, but I'm not sure what the actual manufacture date is, I'll check. The Dash very clearly has a trans temp gauge.
What I've learned is that 210ish isn't too hot, it is close to normal however I'm not running it hard, just cruising on the highway with the Cruise control on.
I did up date my location, can't do a signature because I haven't paid 20 bucks for it.
at what temperature should I expect the fan to kick on?
What I've learned is that 210ish isn't too hot, it is close to normal however I'm not running it hard, just cruising on the highway with the Cruise control on.
I did up date my location, can't do a signature because I haven't paid 20 bucks for it.
at what temperature should I expect the fan to kick on?
#5
06-01-2015, 04:15 PM
Posting Guru
I have an '02, 7.3 4x4 limited, but I'm not sure what the actual manufacture date is, I'll check. The Dash very clearly has a trans temp gauge.
What I've learned is that 210ish isn't too hot, it is close to normal however I'm not running it hard, just cruising on the highway with the Cruise control on.
I did up date my location, can't do a signature because I haven't paid 20 bucks for it.
at what temperature should I expect the fan to kick on?
What I've learned is that 210ish isn't too hot, it is close to normal however I'm not running it hard, just cruising on the highway with the Cruise control on.
I did up date my location, can't do a signature because I haven't paid 20 bucks for it.
at what temperature should I expect the fan to kick on?
When I had my 2000 7.3 SuperDuty I did not know the temps BUT while burning it through the Mexican desert at close to 90MPH in July, the fan kicked in the 1st time & it scared the hell out of me
. Very difficult to diagnose a noise online, BUT I'm thinking that is what is happening & it's normal.
#6
06-01-2015, 04:26 PM
You don't need to pay for a signature, you just need to have at least a set number of posts and to have been a member for a certain period of time, both of which I think you meet currently.
#7
06-01-2015, 06:39 PM
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