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removing mechanical fan for MPG gain

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  #21  
Old 05-10-2014 | 01:34 PM
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Originally Posted by ayoung101
why is the 4.7 at higher risk? is there a common failure that i am unaware of?
It's a cast block with aluminum heads. They heat up and cool down at different temps because they are different metals. This puts stress on the head gaskets and unfortunately it is a very common problem to blow a head gasket on this motor.

There are also a lot of problems with warped heads and dropped valve seats. IMO this motor has a lot of power and efficiency advantages over the 5.2 and 5.9 magnum motors but it's not nearly as bullet proof.

If you overheat a 5.2 you'll be pulled over until it cools. If you overheat a 4.7 there is a very good chance that you're gonna be pulling the heads off. Maybe not even right away, but in the near future.
 
  #22  
Old 05-10-2014 | 03:01 PM
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I didn't have the mechanical fan on my Durango for 2.5 years and never had a problem with it. The summers in Omaha are triple digit worthy as well, and I never had a single issue. I also kept it in the back just in case I needed it though.
 
  #23  
Old 05-10-2014 | 03:06 PM
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Originally Posted by TheNewbie
It's a cast block with aluminum heads. They heat up and cool down at different temps because they are different metals. This puts stress on the head gaskets and unfortunately it is a very common problem to blow a head gasket on this motor.

There are also a lot of problems with warped heads and dropped valve seats. IMO this motor has a lot of power and efficiency advantages over the 5.2 and 5.9 magnum motors but it's not nearly as bullet proof.

If you overheat a 5.2 you'll be pulled over until it cools. If you overheat a 4.7 there is a very good chance that you're gonna be pulling the heads off. Maybe not even right away, but in the near future.
Most NEW engine designs utilize an aluminum head. Almost all the problems you point out, blown gaskets and dropped valves happen to engines that have been overheated. Something caused the engine to overheat and then the damage occurred.
 
  #24  
Old 05-11-2014 | 01:47 AM
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Originally Posted by Dodgevity
I'm in Georgia too and you're a braver man than me. With my constant sitting in midtown Atlanta traffic, that's one mod I won't chance.
I am rarely in the atlanta traffic. I hate it. I live out in South GA, and no traffic at all. Cant stand it. Where are you at?

Originally Posted by that_guy
It's not designed to cool the engine on it's own though, just to be a supplement to the mechanical fan.
Yes I know. I worked at Dodge. BUT the efan is sufficent as its own for the time being. If you are in stop and go traffic like Dodgevity, then I wouldnt do it either. Now that being said, am I afraid to take it to Atlanta, no. I built the motor to run cold, but there have been times I have been afriad, but it has been sufficent and never gotten above 5/8
 
  #25  
Old 05-11-2014 | 01:48 AM
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Originally Posted by MoparMan1991
I didn't have the mechanical fan on my Durango for 2.5 years and never had a problem with it. The summers in Omaha are triple digit worthy as well, and I never had a single issue. I also kept it in the back just in case I needed it though.
I kept mine in the back seat too for a while. Did it just to scope out what the motor would do.
 
  #26  
Old 05-11-2014 | 09:56 AM
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Originally Posted by Dodgevity
But we're not talking about replacing the mechanical fan with an electrical. We're talking deleting it and relying solely on the secondary electric fan that comes with tow package, right?
I sure wouldn't rely on the auxiliary fan without giving it a thorough look see.
I'd be more inclined to lose both and buy or make a dual pull through electric fan. One that will do any cooling job I may encounter. Even single fan technology has come leaps and bounds ahead today.
Many vehicles run just E Fan's now compared to years back.
Updating our old stuff just makes sense.

Yes. The efficiency quotient may not be high. But it is noticeable.
And any efficiency is good.
I needed (thought I needed) major cooling on my old mud truck. I put a 7 blade fan on my 360 from a early 70's Ford Lincoln with a 460. With fan shroud.
Could feel airflow from in front of the truck at idle.
Ok. Overkill. Pulled so much air that at 5000 rpm it pulled the shaft out of two water pumps before I swapped it to electric.
Instantly I noticed a seat of the pants response.
Also noticed that even in Hot 35c weather for days on end my truck ran fine. Yes, big bias ply tires, heavy diffs, etc. My truck was 6500 pounds.
Pulling a trailer was no problem. E Fan only came on in the city in stop and go traffic. On the hwy, never.
Having a mechanical fan was pointless and robbed the engine of HP that could be better used to motivate my right foot.
 
  #27  
Old 05-12-2014 | 09:51 PM
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So.. not sure how i can help here but i think honestly that sitting in hot summer traffic parking lot your gonna run hotter temps no matter what.. 210 is nothing really as long as you dont start boiling uncontrollably past that point. if you can maintain that with AC and never go above i think your doing damn good IMO..

But anyways.. I made a thread and made it to the DIY thread with my e-fan that was on a 97 5.2L using the Jeep liberty recall 19" fan and the stock shroud..

https://dodgeforum.com/forum/2nd-gen...n-setup-5.html

it did really well actually being i was running it during the massive drought and heat wave that hit Texas.. here north of Houston and it did really well but for my comfort with AC and all that I need/want to build a shroud for it then put a controller on it so i dont have to worry with the switch everytime i drive the truck (or the wife...she'll forget) lol..

I suppose i just want to say that I'm not sure what kind of heat difference between the 4.0 in the liberty (my wife had one actually running just the aux fan. ) and the 5.2L but in both cases seemed very well. My wife's ran it in the stock location just pulling air like it would in the HD cooling setup.. and though in heavy parking lot traffic it got up near to 210 it never really got above..

I can say the same for my 5.2L as well.. which has harldy any room to move air with that big bulky 5.2l sitting there.. throwing hot air right on to the engine.. lol.

I can say though watch the CFM ratings ppl post they seem bogus.. I had the HHR fan posing to be big CFM ratings but really it was LULZ at best..
 
  #28  
Old 05-12-2014 | 09:57 PM
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Oh... sorry point I was going to make was that your not really gaining anything by removing the fan other than not having the drag when it's engaged; but you do have some slight drag from your ALT when your pulling the amperage but no where near the same amount..

Your really not gaining anything your simply avoiding using certain amount of HP to spin that fan during times it would other wise be engaged.
 
  #29  
Old 05-12-2014 | 11:05 PM
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Originally Posted by jondakotaguy
Oh... sorry point I was going to make was that your not really gaining anything by removing the fan other than not having the drag when it's engaged; but you do have some slight drag from your ALT when your pulling the amperage but no where near the same amount..

Your really not gaining anything your simply avoiding using certain amount of HP to spin that fan during times it would other wise be engaged.

Even if its not engaged, its still robbing power from the engine. Just because the clutch is not locked, it still has to spin even if its free.
 
  #30  
Old 05-13-2014 | 12:56 PM
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Long story short... nobody can tell you if it will work for sure in YOUR truck in YOUR part of the country with the weather and driving conditions that YOU will be facing.

All I know is that running completely without a fan in the winter months was fine for me. And if you do decide to try this just make sure to keep the fan in the back seat or in the bed of the truck. As long as you keep an eye on the temp gauge the worst case scenario is that you might have to pull over, shut the truck off, thread the fan back on and fire up the engine with the fan again. All of that should take well less than a minute, so I'd say go for it but just keep an eye on the gauges.
 


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