Some mornings my truck will sound like a huge fan. If I get the RPMs up it will stop. It doesn't do this every morning even if the outside temp is the same as the day before. My fan apears to be a belt driven clutch fan like every other vehicle I own. Does this fan have an electric clutch like an A/C compressor? If so why would it not be consistently on or off at cold start?

Thanks for any help!!!

Search for "morning sickness".
I c/p this from one of the threads...it sums it up well:
"The fluid in the fan clutch drains out over night engaging the fan when you start it. Its perfectly normal and most of these trucks do it.

Nothing to worry about."

Yep, my 2002 does that once the temps drop a bit. It's normal until the fluids start warming up....I think it has to do with the Allison. Not to worry!

Wayne

your not the only that has posted this same thread. take a gander look around.

http://dieselplace.com/forum/showthread.php?t=179814&highlight=morning+sickness
http://dieselplace.com/forum/showthread.php?t=124100&highlight=morning+sickness

its the oil in the fan clutch being thick and makign the fan turn when its not warmed up. w/thsese diesels being so quite now adays you notice other noises more

It sounds like a huge fan because it's well, a huge fan :D. Viscous silicone fluid in the clutch settles overnight and takes a few moments to be evacuated from the main chamber (fan clutch disengages) in the morning when cold.

Mine also roars for a short distance after start up. Never had it hot enough to make the fan come on while towing though.

I know the feeling!


:)

If you let your engine warm up first,you won't hear it.I always let mine warm up,even in the Summer.Any diesel is much happier warmed up before pouring the coals to her,you don't have a gasser anymore.

our duramax does it and so does my colorado, nothin to worry about, its normal.

Mine also roars for a short distance after start up. Never had it hot enough to make the fan come on while towing though.

It might be coming on and you're not catching it. Mine goes on and off when towing - I usually don't hear it, but I see it when the coolant temp drop below normal (not the thermostat opening/closing). I first put the two of those together when I heard the fan roar as the engine dropped to idle and then accelerated after running a couple of hours.

I hear mine do it every morning

If you let your engine warm up first,you won't hear it.I always let mine warm up,even in the Summer.Any diesel is much happier warmed up before pouring the coals to her,you don't have a gasser anymore.

I never understand this advice. All engines, diesel or gas, should be at operating temperature before "pouring the coals to her." Why should diesels be any different? I think this reasoning comes from many decades of OTR trucks idleing in truckstops. The difference is they usually HAVE TO idle for heat/ac.

As for not having morning sickness (fan) if it is warmed up first...maybe so. But with $3/gallon fuel, I will gladly listen to a mile or two of fan while my truck is actually getting me somewhere (gently till it's warm, or course :)) instead of wasting it idleing in the driveway.

As for not having morning sickness (fan) if it is warmed up first...maybe so. But with $3/gallon fuel, I will gladly listen to a mile or two of fan while my truck is actually getting me somewhere (gently till it's warm, or course :)) instead of wasting it idleing in the driveway.

:agreed:

Never had it hot enough to make the fan come on while towing though.


If the fan clutch is operated by oil/viscous silicone fluid how does it turn on and off as you say. Does the fan have an electronic control system. If so why would it use fluid if it can come on and off on its own with engine temp rise?

Mine fan come on alot also...

I never understand this advice. All engines, diesel or gas, should be at operating temperature before "pouring the coals to her." Why should diesels be any different? I think this reasoning comes from many decades of OTR trucks idleing in truckstops. The difference is they usually HAVE TO idle for heat/ac.

As for not having morning sickness (fan) if it is warmed up first...maybe so. But with $3/gallon fuel, I will gladly listen to a mile or two of fan while my truck is actually getting me somewhere (gently till it's warm, or course :)) instead of wasting it idleing in the driveway.

You miss the point entirely.Diesels rely on heat much more than a gasser--AKA NO SPARK PLUGS!!!You are doing your Dmax good when you let it idle to warm up.Sure,you can just start it,put it in gear and go,but it's not correct.Our trucks were not made for quick jaunts to get momma some milk at the corner store.

notice how they don't warm up like gassers do? they make very little heat at idle. the only way to warm them up (they perform best and are happiest at operating temperature) is to put a load on them. albeit a light load, like in my case idling down a long driveway, and then being super easy on 'er until she shows temp.

all the warmin' up she needs is the 3 seconds it takes until that glowplug light goes off.

my opinion.

If the fan clutch is operated by oil/viscous silicone fluid how does it turn on and off as you say. Does the fan have an electronic control system. If so why would it use fluid if it can come on and off on its own with engine temp rise?

Silicone fluid acts differently than most other fluids when hot, instead of thinning out, it thickens (becomes more viscous).

So, compound the fluid for a desired operating temp in the clutch, when it gets hot, it starts turning the fan.

I never understand this advice. All engines, diesel or gas, should be at operating temperature before "pouring the coals to her." Why should diesels be any different? I think this reasoning comes from many decades of OTR trucks idleing in truckstops. The difference is they usually HAVE TO idle for heat/ac.


I'll probably regret saying this, but OTR trucks don't usually have to idle, this comes from decades of truckers wanting to be comfortable AND NOT paying for the diesel.

These tractors should indeed be at least partially warmed up before asked to pull their payloads, so there is some logic to them idling while hooking up, safety checks, etc.

But like all vehicles, once they are warmed up, they're fine. There's all sorts of excuses for it -


Who's going to notice whether I get 4.5 or 5 mpg?
I don't like having to waste ether
It's hard on my batteries
It's hard on the engine to warm up and cool downPeople paying for their own diesel are shutting down more now. And the trucking companies are starting to watch the fuel consumption for each truck/run.

The most hilarious/sad thing is watching someone with a diesel pickup idling while fueling up. Unless it's well below freezing, there's no need for it - unless you are in a cool down from towing or hard driving or you just fired it up from a cold below 0 deg F start. But when you ask some of these folks, they obviously think that they're one of the big rigs... One fellow told me that his owner's manual said he had to let it idle for 5 minutes before shutting down after every use. I told him that must be a blast after driving 2 minutes to the grocery store - I got the glare for that one.

(And yes, I do idle down for a few minutes after towing just to let everything mellow out.)

Here's a good analogy: diesels are like women,the more you warm them up,the hotter they will perform,the longer they will perform,the better they will perform,and maybe,just maybe now,they might like you for it.Now,can you few guys who just start and drive maybe understand that? You do have some knowledge of women here right?:D

wtf is foreplay? and why do my girlfriends keep leaving me? :D

I'll probably regret saying this, but OTR trucks don't usually have to idle, this comes from decades of truckers wanting to be comfortable AND NOT paying for the diesel.

These tractors should indeed be at least partially warmed up before asked to pull their payloads, so there is some logic to them idling while hooking up, safety checks, etc.

But like all vehicles, once they are warmed up, they're fine. There's all sorts of excuses for it -


Who's going to notice whether I get 4.5 or 5 mpg?
I don't like having to waste ether
It's hard on my batteries
It's hard on the engine to warm up and cool downPeople paying for their own diesel are shutting down more now. And the trucking companies are starting to watch the fuel consumption for each truck/run.

The most hilarious/sad thing is watching someone with a diesel pickup idling while fueling up. Unless it's well below freezing, there's no need for it - unless you are in a cool down from towing or hard driving or you just fired it up from a cold below 0 deg F start. But when you ask some of these folks, they obviously think that they're one of the big rigs... One fellow told me that his owner's manual said he had to let it idle for 5 minutes before shutting down after every use. I told him that must be a blast after driving 2 minutes to the grocery store - I got the glare for that one.

(And yes, I do idle down for a few minutes after towing just to let everything mellow out.)

Agreed. All of this "diesels have to be warm...let them idle...you're not in a gasser...blah...blah" BS is living in the past. My wallet and I live in the now.:)

Guess I wasn't clear enough. When I say truckstops I mean pulled over for the night to sleep...not just getting fuel.

I'll bet dollars to doughnuts your LLY is either your first,maybe second diesel,correct? You keep doing what you're doing,your Dmax will probably be just fine for many thousands of miles.The difference is mine will love me more for being nicer to her if you will,because anyone who has run diesels for a while knows they need to be warmed up first before driving off.Did you also forget how much ATF is in our Allys that also needs to flow for a few minutes to thin out and warm up?Did you ever put yourself under your ride and listen to that giant pump we have pushing that cold ATF around?I didn't think so.Do you think I start up my John Deere backhoe and start digging immediately? Not in this lifetime.It's called common sense,plain and simple.

First off, if you are driving away and your fan is ROARING you're likely abusing your engine. That 90+ psi of oil pressure you see on the guage gets that way cause the oil is thick and is resisting flow! Ya it doesn't have to sit in the drive way idling for 20 minutes but if you drive away easy the truck will rarely rev above 1500 rpm and the roar is not that loud. After a mile or so it will kick off. So unless your driveway is connected to the interstate you should be able to drive off easy and nice.

Second, To the mods, why can't we make this subject a sticky? Maybe new folks find the search too confusing or something because we end up with a thread on this it seems every few weeks.

i start my lbz and drive to work right away, Then I get out and start my sterling right away and drive off. I let it warm up while im rolling

Maybe new folks find the search too confusing or something because we end up with a thread on this it seems every few weeks.

Add the "Should I Block n' Finger my truck?" threads to that list. And the "Why doesn't my truck blow smoke?" and "LBZ vs. LMM",...

Add the "Should I Block n' Finger my truck?" threads to that list. And the "Why doesn't my truck blow smoke?" and "LBZ vs. LMM",...
One more to the list would be "What kind of mileage are you guys seeing?" And how about "what size tires will fit without a lift/with leveling kit?"

let ur truck warm up for about 15 to 20 mins before u leave and it will not do it?

let ur truck warm up for about 15 to 20 mins before u leave and it will not do it?

CORRECT

I'll bet dollars to doughnuts your LLY is either your first,maybe second diesel,correct? You keep doing what you're doing,your Dmax will probably be just fine for many thousands of miles.The difference is mine will love me more for being nicer to her if you will,because anyone who has run diesels for a while knows they need to be warmed up first before driving off.Did you also forget how much ATF is in our Allys that also needs to flow for a few minutes to thin out and warm up?Did you ever put yourself under your ride and listen to that giant pump we have pushing that cold ATF around?I didn't think so.Do you think I start up my John Deere backhoe and start digging immediately? Not in this lifetime.It's called common sense,plain and simple.

Well, in my case, it is my 9th diesel vehicle, ALL of which have gone several hundreds of thousands of miles, with never an engine or oil consumption or compression problem, by letting it warm up long enough to have the oil pressure on the gauge. Over the past 33 years. Add another half a dozen diesel tractors and skidloaders over the past 40+ years of diesel usage. Maybe someday I'll have a little bit of experience with the diesel engine... And I think I would put that up against the folks who didn't start using diesels when TAXED diesel was 19 cents a gallon.

The nicest thing you can do for a diesel is start putting a light load on it to help it warm up. Then they really like you because they aren't idling with no work to do.;)

''These tractors should indeed be at least partially warmed up before asked to pull their payloads, so there is some logic to them idling while hooking up, safety checks, etc.

But like all vehicles, once they are warmed up, they're fine. There's all sorts of excuses for it -''

Kind of contradicts your last post there Wynot--Is this mean what you say or say what you mean here?????????? I for one am confused here with what you're saying.Please enlighten this excavating contractor who's been operating iron for 33 years now,with many,many,diesel fired pickups and dumps.How many owner manuals would you like to see that clearly explains to warm up at the very least the engine,not to mention the rest of the drive train,including the hydraulics?The light load you mention is fine,but only after minimum 5 minutes idle time,more if it's cold out.

''These tractors should indeed be at least partially warmed up before asked to pull their payloads, so there is some logic to them idling while hooking up, safety checks, etc.

But like all vehicles, once they are warmed up, they're fine. There's all sorts of excuses for it -''

Kind of contradicts your last post there Wynot--Is this mean what you say or say what you mean here?????????? I for one am confused here with what you're saying.Please enlighten this excavating contractor who's been operating iron for 33 years now,with many,many,diesel fired pickups and dumps.How many owner manuals would you like to see that clearly explains to warm up at the very least the engine,not to mention the rest of the drive train,including the hydraulics?The light load you mention is fine,but only after minimum 5 minutes idle time,more if it's cold out.

The tractors I am referring to in the earlier post are OTR type tractors, pulling 80,000 lbs. By the time air tanks are dumped, hydraulics checked, etc., most of them should probably be able to pull just fine. Your dumps are probably in the same category. Farm type tractors, and my experience with skid loaders, bulldozers, and backhoes, I usually just fire them up and start working lightly and increase from there. I defer to your experience with the excavation type usage.

If I am pulling my trailers, I generally have taken the tow vehicle, and gone somewhere else with it first. May be breakfast, may be getting fuel, may even be just simply maneuvering into position and hooking up, brake check, light check, but not much more. But I never intentionally do more than get pressure on the oil pressure gauge if I am just running the P/U truck itself or any of the other diesel road (not Heavy duty vehicles). Even my years in the Air Force and Army running 2.5 and 5 ton trucks didn't want them idling for warm up (by order of the vehicle maintenance people).

Maybe I'm confused with what is being referred to as warmed up. I personally would define warmed up as at full operating temp (whatever definition one wants for that), maybe another person defines it as starting to register on the gauge. I know nothing about dump trucks (other than a broken windshield from one, a dented hood from another, and a broken headlight from a third). I know that when I have gravel brought in, that they are quite heavy, with about 23 tons of gravel on a triple axle.

If you're content warming up whatever for however long, that's your choice. I'm not trying to make you change. My only point is that my experience has shown "me" that my diesel-powered equipment continues to work just fine not doing it, so a statement that it won't last as long if you don't just doesn't hold up FROM MY PERSONAL EXPERIENCE.

It's kinda like saying a vehicle doesn't run as long on conventional motor oil as it will on synthetic - how would you know - because you only have one time for that vehicle. Same thing here, you warm them up all the time, I usually don't - you don't have engine related failures warming it up, but neither do I not warming them up. Neither of us will ever know if it makes a difference.

I LOVE HOW ON THIS SITE THE ORINGINAL POST IS COMPLETELY FORGOTTEN AFTER THE FIRST OR SECOND PAGE. All you guys are doing is arguing about something that is not the topic at hand. Maybe if you want to discuss warming up diesel engines you should start a new thread or go to one about that topic

I LOVE HOW ON THIS SITE THE ORINGINAL POST IS COMPLETELY FORGOTTEN AFTER THE FIRST OR SECOND PAGE. All you guys are doing is arguing about something that is not the topic at hand. Maybe if you want to discuss warming up diesel engines you should start a new thread or go to one about that topic
Not that we shouldn't stay on topic so information isn't lost but was there anything else having to do with the original topic that needs to be discussed?

Should I block and finger my truck?

The tractors I am referring to in the earlier post are OTR type tractors, pulling 80,000 lbs. By the time air tanks are dumped, hydraulics checked, etc., most of them should probably be able to pull just fine. Your dumps are probably in the same category. Farm type tractors, and my experience with skid loaders, bulldozers, and backhoes, I usually just fire them up and start working lightly and increase from there. I defer to your experience with the excavation type usage.

If I am pulling my trailers, I generally have taken the tow vehicle, and gone somewhere else with it first. May be breakfast, may be getting fuel, may even be just simply maneuvering into position and hooking up, brake check, light check, but not much more. But I never intentionally do more than get pressure on the oil pressure gauge if I am just running the P/U truck itself or any of the other diesel road (not Heavy duty vehicles). Even my years in the Air Force and Army running 2.5 and 5 ton trucks didn't want them idling for warm up (by order of the vehicle maintenance people).

Maybe I'm confused with what is being referred to as warmed up. I personally would define warmed up as at full operating temp (whatever definition one wants for that), maybe another person defines it as starting to register on the gauge. I know nothing about dump trucks (other than a broken windshield from one, a dented hood from another, and a broken headlight from a third). I know that when I have gravel brought in, that they are quite heavy, with about 23 tons of gravel on a triple axle.

If you're content warming up whatever for however long, that's your choice. I'm not trying to make you change. My only point is that my experience has shown "me" that my diesel-powered equipment continues to work just fine not doing it, so a statement that it won't last as long if you don't just doesn't hold up FROM MY PERSONAL EXPERIENCE.

It's kinda like saying a vehicle doesn't run as long on conventional motor oil as it will on synthetic - how would you know - because you only have one time for that vehicle. Same thing here, you warm them up all the time, I usually don't - you don't have engine related failures warming it up, but neither do I not warming them up. Neither of us will ever know if it makes a difference.

Now I see where the confusion lies.No,Wynot,I don't mean full operating temp--just warmed up some,that's all.Now,if we're talking cold out and something like a hoe-ram on a backhoe,you should allow about 30 minutes of warm-up to get that hydraulic oil thinned out--extremely important.And sorry to all for getting off topic.

Should I block and finger my truck?

Only if your wife/GF isn't handy.:D

thanks for the info

Hey BIGR! That avatar looks real familiar! I think I worked on that A/C.........;)

Every time my fan is on I think 4.3 chevy,

Every time my fan is on I think 4.3 chevy,

):h

My neighbor has a '90ish S10 SUV that wakes me up every morning. Its the perfect alarm clock, I don’t know what I would do if they ever got rid of it.

Well, I would have to rely on the other neighbor with a 7.3L powerstroke. That thing could wake the dead :eek:

I love that sound!