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Does anyone else's 5.7 engage the fan when starting in 1st gear? Seems like I can hear my fan engaged until about 2500 rpm in 1st gear, both when the truck has recently been started, and when it is completely warmed up. It's kind of annoying because it makes alot of noise, and it saps a little power off the line...

Has anyone else noticed this?

:ts:
 

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I don't notice that at all...sorry. When first started cold...yes but after that...no. I make it habit to turn off the HVAC system and just about everything else when I am done playing with her for the day.
 

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Thanks for the input so far. Anybody else?

I just want to clarify, I have noticed the fan with the HVAC system on and off with the A/C both on and off. It is only in 1st gear when starting from a stop and the fan disengages above about 2500 rpm. Hardly a problem, just a little annoyance.

If it seems to be unique to my truck what could it be? A sticking fan clutch? A bad coolant temp regulator/thermometer? My coolant temps look good from the dash, and it hasn't been hot here...
 

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Discussion Starter #5
Bump...Anyone else??

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Pretty normal for most HD fan clutches driving a high pitch fan blade, at least at cold start. The oil must be dispersed by centrifugal force. Usually after a hard drive and a quick stop like at an interstate exit you will get partial engagement at takeoff. Same thing when restarting engine after a 3-10 min hot soak. It has to have partial engagement; at least enough to pull air through radiator, condensor, other coolers so bi-metalic spring can sense temp. It is a big engine with a big cooling system, I bet it really makes a noise at the top of a hill on a summer day pulling a trailer. As far as the guage goes, most vehicles today use a "dummy" guage; at any where from 10° below and 20-25° above the t/stat setting the guage sits in the same spot. Unless it really seems to do it all the time I bet it is OK.
 

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Pretty normal for most HD fan clutches driving a high pitch fan blade, at least at cold start. The oil must be dispersed by centrifugal force. Usually after a hard drive and a quick stop like at an interstate exit you will get partial engagement at takeoff. Same thing when restarting engine after a 3-10 min hot soak. It has to have partial engagement; at least enough to pull air through radiator, condensor, other coolers so bi-metalic spring can sense temp. It is a big engine with a big cooling system, I bet it really makes a noise at the top of a hill on a summer day pulling a trailer. As far as the guage goes, most vehicles today use a "dummy" guage; at any where from 10° below and 20-25° above the t/stat setting the guage sits in the same spot. Unless it really seems to do it all the time I bet it is OK.
It is just partial engagement, but if mine does it and nobody else's does then what?? :confused:

I can learn to ignore it, I'm just not used to it since my V8 4Runner didn't do it unless it was really hot out.

Thanks for the opinions though :tu:
 

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My 4.7 is like that at start up for about a minute or so. It also makes a "chirp" when it kicks out. After that it purrs like a kitten. I not too concerned about it every toyota truck I've owned was always a bit "noisey" at start up.
 

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The fan clutch could misadjusted slightly for an early cut-in. If you think it is engaging when it shouldn't just take it to dealer. They will prob swap out clutch for another.
 

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Mine does it everytime I start it, so I assume its normal..It doesnt affect any functionality of the truck. One of those little things that Ill have to live with for 20 years, but I think I can manage it :). (something about the power of the 5.7 makes everything alright with this truck anyhow!!:devil::tu:)
 

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Mine does it everytime I start it, so I assume its normal..It doesnt affect any functionality of the truck. One of those little things that Ill have to live with for 20 years, but I think I can manage it :). (something about the power of the 5.7 makes everything alright with this truck anyhow!!:devil::tu:)
Stig, thanks for your response (I'm honored to be conversating with a faceless, voiceless driver :eek: :D ;) ). Anyways, my fan, as I'm sure everybody's runs during startup. I'm looking for people who have this happen when the truck is warmed up starting from a full stop. Does yours do this?
 

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Stig, thanks for your response (I'm honored to be conversating with a faceless, voiceless driver :eek: :D ;) ). Anyways, my fan, as I'm sure everybody's runs during startup. I'm looking for people who have this happen when the truck is warmed up starting from a full stop. Does yours do this?
Mine does it only when I 1st start it up (reguardless of temperature or how long I've previously ran the truck) but once it idles for about a min or so it goes away. It doesnt do it say for example when taking off from a red light from a stand still
 

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... It doesnt do it say for example when taking off from a red light from a stand still
This is what I'm looking for, mine does it, but only breifly. Thanks!
 
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