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3.0 towing and cooling


JamesC

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In the owners manual it mentions if you are towing with the 3.0 on a hot day to not exceed certain speeds.

Would adding an electric fan in front of the rad in addition to the stock clutch fan help prevent overheating while towing? I would install it on a switch and only use it while towing.
 


Will

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I doubt it. I would guess that if you could manage to cover more area of the radiator with fan it would help, but there's probably only so much heat you can blow out of the center of the radiator. The fan that is there is shrouded to try and pull from the whole radiator. A higher capacity radiator is the fix if you are overheating. If you aren't overheating I wouldn't do anything.

Think about this--you can slap your hand on something hot and pull it back and not feel pain. But leave it there and the heat will have time to transfer. I think it's possible to have too fast of air and too fast of coolant flow. If I were going to improve my airflow I might consider getting rid of the engine fan and using a pair of electric fans on the inside best positioned to cover as much of the radiator as possible.
 

thegoat4

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Just watch your temp gauge and stay out of 5th gear.

If you start to get too hot, slow down. Otherwise, drive at the speed limit or a little below. You also have the option of dropping down another gear and racing the engine for a little bit. I have 3.73 gears and can drive 70MPH in 3rd gear. The 3.0 will take that just fine all day long, too. The increased RPMs will allow for a higher fan speed, plus you'll be moving more air through the engine itself. Both effects will increase the rate at which your engine can shed heat.

Adding another fan really won't help. Don't switch to all-electric fans either. You'll have less ultimate cooling capacity after spending that money.

Will's hand-slap theory is backwards--you aren't concerned with the temp of the hands, you're concerned with the temp of that hot surface. Blowing air slowly over a hot radiator core will get that air hotter, while blowing air quickly over a hot radiator will not get that air as hot. But in the second scenario, you have such a larger volume of air, the total heat transfer is higher.

Also, if you have a CEL on, fix it. Some conditions that turn on the CEL will also contribute to running hot.

I find that if I stay in the right lane on the interstates and highways, there's enough traffic to keep me going slowly enough to not have any heat issues at all. And FWIW, I've wildly overloaded my little pickup during Texas summertime and the temp needle settled at very slightly warmer than 1/2, which is where it usually stays. But, of course, it's pretty much flat here.
 

Will

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Don't switch to all-electric fans either. You'll have less ultimate cooling capacity after spending that money.
How is that? Electric fans work great. Everything new has them. I'm not saying they are better, but I am saying having more area of your radiator with a fan blowing straight through it is better than a single one in the middle--shroud or not.

Will's hand-slap theory is backwards--you aren't concerned with the temp of the hands, you're concerned with the temp of that hot surface. Blowing air slowly over a hot radiator core will get that air hotter, while blowing air quickly over a hot radiator will not get that air as hot. But in the second scenario, you have such a larger volume of air, the total heat transfer is higher.
Heat transfer takes time, that was my point.
 

Wicked_Sludge

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the stock mechanical fan is something like 18" across. its a beast. replacing it with a dinky 16" fan or even smaller dual fans is not going to help anything...only hinder. furthermore, the stock fan has enormous blades and all the power in the world it needs to spin. e-fans are limited to the power their motors can produce.

lots of vehicles come with e-fans, but no trucks that are meant for towing ..only minivans and cars. and even in those instances, those vehicles come equipped with larger radiators comparitivly to compensate for the lower e-fan CFM.

(and here we go with the e-fan arguement....again)

about the heat transfer, im going to have to agree with the goat on this one. your radiator is touching the air 100% of the time...so your burning your hand example is irrelevent. CFM is where its at.

a dual-core radiator out of an explorer is right up your alley :icon_thumby:
 

Will

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I agree about the dual core. You guys are focusing in on the parts of my post you want to argue about.

First, I didn't say electric was better. I said full coverage was better--for this truck. I got a jump when the battery died in my bus by a brand new 2008 full-size Chevy pickup and it had electric fans. I do not know what motor but it was a service station truck. I'm sure it makes more heat and can pull more than a 3.0, whatever it is. I think a 3.0 comes with too much fan power for what it needs. I said adding a fan wouldn't help because I meant it. The vehicle that can't get by on an electric fan is probably a HD diesel pickup and above.

Next, since I don't think adding a fan would help, I don't think adding a fan will help. Blow all you want through that radiator with a jet engine powered fan and it isn't going to get rid of the heat any faster because that's how fast that radiator can give up it's heat. I don't know how much of the radiator is covered by the fan. But the parts that aren't covered are moving very little area. Blowing really hard at one spot isn't as good as blowing at the whole thing. That's just my opinion. But having 2 or 3 little fans on the radiator works as well as a big mech fan in most vehicles.
 

Wicked_Sludge

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yes chevy puts e-fans in its 1500 pickups. the heavy duty package got a mechanical fan upgrade.

the stock mechanical fan covers about as much of the radiator as one could hope to cover (only the corners arent covered...you know, round peg, square hole...and this is made up for by the mechanical fans proper fan shroud).
 

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Not to get into the e-fan argument, but the stock mechanical fan with a shroud will pull air through every square inch of the radiator core just fine. Adding another fan on top of what's there won't improve cooling. Switching to multiple small fans won't improve cooling either.

The speed at which a radiator can shed heat depends on the temperature difference between the surface of the radiator and the air touching it. A bigger temperature difference leads to a higher heat transfer.

With air blowing through a radiator core, the air is your heat sink, and the radiator is your heat source. For figuring out minimum heat transfer rates, you look at the highest temperature of your heat sink vs. the lowest temperature of your heat source. Fast-moving air will leave you with a cold heat sink. Slow-moving air will leave you with a hot heat sink. Take it to the extreme, shut off the fan and your heat sink will soon assume the same temperature as your heat source and you will have no more heat transfer. Going the other way, higher air flow yields a cooler heat sink, yields a faster heat transfer.

More air flow == more cooling capacity. Running down the highway at 70MPH will move more air through your radiator than any fan arrangement will. At that point you're relying on your thermostat to restrict coolant flow through the radiator to prevent overcooling the engine.

I said the OP would have less ultimate cooling capacity because all of the electric fans currently available for the Ranger move less air than an 18", steeply-inclined fan capable of spinning over 4,000rpm can move. Most of the time that won't matter, but the OP was curious about bumping up against the limits of the cooling system's capacity.

His stock system should handle whatever he's doing just fine. If it doesn't, he most likely has a mechanical problem that needs fixing before than upgrading to multicore radiators and extra fans.

Chevy should not be an example of how to do anything.
 

Will

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Chevy should not be an example of how to do anything.
It does sort of stick a screwdriver in the spokes of your thesis, doesn't it? Especially when there are other people, like Honda and Toyota--who are not spiraling down the tubes incidently--that also use e-fans in SUVs and pickups.

I don't deny the gist of your argument, only the scale of it. Mechanical fans aren't used because they are needed in sub 15,000# GCWR vehicles, they are used because they are cheap and easy.
 

JamesC

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I'm not having a cooling problem I am just trying to make sure I don't have one. as I said before I read in the owners manual that on hot days with a 3.0 you should stay below a certain speed.

I think one of those electric fans in addition would help, would my money be better spent on a different rad and if so which ones fit? or is there a better mechanical fan to use? an electric fan in addition seems the best option to me but I want others opinions, lots of vehicles come with a electric fan and mechanical one these days, almost everything BMW or Mercedes. Dodge Durango's have both as well.

the truck I have is a 2005 3.0 2wd btw
 
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thegoat4

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It does sort of stick a screwdriver in the spokes of your thesis, doesn't it? Especially when there are other people, like Honda and Toyota--who are not spiraling down the tubes incidently--that also use e-fans in SUVs and pickups.

I don't deny the gist of your argument, only the scale of it. Mechanical fans aren't used because they are needed in sub 15,000# GCWR vehicles, they are used because they are cheap and easy.
I agree that they're cheap and easy, but they also happen to have more ability to move air.
 

thegoat4

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I'm not having a cooling problem I am just trying to make sure I don't have one. as I said before I read in the owners manual that on hot days with a 3.0 you should stay below a certain speed.

I think one of those electric fans in addition would help, would my money be better spent on a different rad and if so which ones fit? or is there a better mechanical fan to use? an electric fan in addition seems the best option to me but I want others opinions, lots of vehicles come with a electric fan and mechanical one these days, almost everything BMW or Mercedes. Dodge Durango's have both as well.

the truck I have is a 2005 3.0 2wd btw
If you're only doing light towing, what you've got now is fine. If you plan to do regular heavy towing, put your money towards 4.10 gears. If you just really want to spend some money on your cooling system, drop in the thicker radiator.

I haven't personally looked at the setups that use both kinds of fans, but as I understand it from what I've read, the mechanical fan is for cooling the engine and accessories and the e fan is strictly for the ac system.
 

Wicked_Sludge

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the mechanical fan is for cooling the engine and accessories and the e fan is strictly for the ac system.
youve got it right. e-fans have started appearing on vehicles along with mechanical fans these days due to the relatively poor performance of R-134A. people dont like their a/c warming up while the vehicle is idling on a hot summer day.

james: i would take a test run with whatever load you plan on towing. chances are very good that your current cooling system will be more than adiquate for your needs (i exceeded my vehicles GCWR in mid may on my way through eastern washington and i didnt have cooling problems...even coming up the gourge). if its not, a bigger radiator is your FIRST step. a 2-row one out of a 4.0 explorer bolts right in....but you will need to obtain the correct fan shroud from a junkyard.

adding electrical fans along with the mechanical fan would only help you if your towing at low speed or in stop and go traffic. when your moving down the road at highway speed, the ambient airflow created by the vehicles motion is already flowing more air than any cooling fan setup will produce.
 

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In order to move air and cool the engine fans need RPM and diameter.

A big ol mechanical fan turning at even 1800-2000RPM is going to move a ton more air then the little electric motor can turn a electric one.

Honda and toyota dont build real trucks either, anything with unibody, IRS, and a unified cab/bed shouldnt be considered a real truck.

later,
Dustin
 

Will

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At least no facts were killed in the making of that argument.
 

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