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Unread 11-20-2012, 10:01 AM   #1
Zew
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5.9 Cooling Fan causes extreme voltage drop when it turns on

Anyone have this issue before? My 5.9 has been running above 210 lately. Starting last friday I noticed that when stuck in traffic mostly, and the fan is constantly turning off and on a lot... my volt gauge drops down into the 10v range and the lights were dimming and flickering a bit. Figured it was just the alternator (was original - had 120k on it) so I bought a new one and installed it (130 amp). The next time i was caught in traffic the voltage drops, but not as badly and no light flickering. I happened to have the radio off and when the fan kicks on, i can hear what sounds like a old school camera flash charging up sound coming from the right kick panel inside the cab.

Another thing that I know isn't right is that the fan makes the whole vehicle vibrate when it turns on. It's almost like sitting at a railroad crossing and having a freight train come by... well... maybe not that bad but close.

I'm guessing my fan is going bad. And I don't there there's anywhere to buy new ones right? I found a few on car-part.com but i'm hesitant to buy a used one cuz who knows how long it'll last. Could it be a relay going bad?

Anyone have this issue happen and have a solution?

Thank you ahead of time for any replies!

-Paul

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Unread 11-20-2012, 10:28 AM   #2
Marcos
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Can you tell if the low speed it coming on first, or if it's going straight to high speed? If the low speed wasn't working, then the engine would get a little hotter until the high speed switch gets triggered. The high speed would draw more power from a standstill than would the low speed or the high speed kicking up from low.

Just a thought.
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Unread 11-20-2012, 10:36 AM   #3
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Back when i was having issues with my a/c not working right, I was asked to check the low speed fan. It was turning on... but for all I know, maybe its not now. The voltage drop stays till the fan turns off. It doesn't just dip then come back up.

When the a/c is off, when is the low speed fan supposed to turn on?

Also, what's with that weird bird chirp noise from the kick panel when the high speed fan kicks on? That can't be normal.

Plus the fan vibration? Just doesn't seem right.
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Unread 11-20-2012, 10:58 AM   #4
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When my alt started going bad the volts would drop very low. I tried a 136 amp alt and it didn't work so well so I took my 150 alt to a shop and exchanged it for a rebuilt 150. Works great now.
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Unread 11-20-2012, 12:04 PM   #5
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I don't think its the alternator. Even with the stock 90amp this wasn't an issue before.

I never heard that noise coming from the passenger kick panel prior to this. The fan vibrates a lot when its in high speed mode. The engine doesn't stay below 210 anymore, not even on cold days. There's no reason a 150amp alternator should be in place when a 90 amp was what the factory put in it. There's clearly something wrong here. Adding more amperage is only going to leave me stranded somewhere if the fan decides to quit.

There has to be someone out there that has had the same issues/symptons i'm experiencing. I need that person to chime in. I can clutch at straws all day and be a parts changer but I don't have the time or want to blow the money.
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Unread 11-20-2012, 12:09 PM   #6
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Might be a ground issue. Check your chassis and engine grounds.
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Unread 11-20-2012, 12:14 PM   #7
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I just had to redo the battery terminals because they were both toast. The chassis ground looks fine. Did not look at the engine ground. I will check that.

But is it normal for the fan to vibrate as much as mine is? It seriously sounds like a diesel locomotive when it kicks on. You can feel it vibrating the vehicle. I'm thinking the bearings in the fan are going out, which is causing it not to spin freely which draws more amps to keep it moving.

Thoughts?
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Unread 11-20-2012, 12:30 PM   #8
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I would pull the fan assembly and check the condition. Check for damage to/ buildup on the blades, and for smooth, quiet rotation of the motor.

If the motor is bad, you can try flushing it out with WD40 (worked for someone on here). Or there's a ford fan motor that works, you just have to get the ford pigtail and make a jumper harness for your vehicle wiring.

If it's a problem with another part of the fan, you could check ebay, they pop up eventually. Or I have a spare at home that I'd be willing to part with (PM me)
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Unread 11-20-2012, 12:35 PM   #9
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Just a follow up, anything mechanically wrong with the fan will cause it to draw more current, which can be felt as vibration when the load on the alternator and engine increases. Or the Alternator could be bad (you stated a 90a was put in there, but 5.9's came stock with 150a) which could also manifest as greater load and vibration.

Different frequencies of vibration will cause different, seemingly unconnected parts of the vehicle to vibrate if the right harmonics are achieved. Hard to know exactly what the chirping noise you're hearing is.
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Unread 11-20-2012, 12:52 PM   #10
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Quote:
Originally Posted by Zew View Post
when the fan kicks on, i can hear what sounds like a old school camera flash charging up sound coming from the right kick panel inside the cab.
-Paul
My DC controls fan controller made that exact same noise, but the sound came from the fan motor. It is caused by pulsed DC, which controls the fan speed and is by design. Maybe the relay or the temp switch that engages the relay is bad. I would hook the fan directly to the battery and see how it acts.
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Unread 11-20-2012, 01:50 PM   #11
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Quote:
Originally Posted by Zew View Post
. There's no reason a 150amp alternator should be in place when a 90 amp was what the factory put in it.
.
5.9= 150 amp stock . I don't know if they are available even at the dealer , no parts stores for sure . There are other options .

In 98 , there were 3 options 150 amp , 136 amp , 117 amp .

I think your fan is tired . It will draw noticably on the guage when it engages , but should be handled fine . Mine was like yours before changing the fan , huge draw , and noisy when winding up . I'm still running the stock alternator 140k
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Unread 11-20-2012, 01:56 PM   #12
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Quote:
Originally Posted by Zew View Post
I don't think its the alternator. Even with the stock 90amp this wasn't an issue before.

I never heard that noise coming from the passenger kick panel prior to this. The fan vibrates a lot when its in high speed mode. The engine doesn't stay below 210 anymore, not even on cold days. There's no reason a 150amp alternator should be in place when a 90 amp was what the factory put in it. There's clearly something wrong here. Adding more amperage is only going to leave me stranded somewhere if the fan decides to quit.

There has to be someone out there that has had the same issues/symptons i'm experiencing. I need that person to chime in. I can clutch at straws all day and be a parts changer but I don't have the time or want to blow the money.
you're mistaken, the 5.9 had the biggest alt they made, stock. 150/160 amp
those fans move a lot of air and require a lot of amperage. if you've been trying to run it on such low output, it's been sucking the battery dry.
it also has a negative effect on motors running them outside of peak voltage and could have cause coil damage.

i would jump the fan directly to a good battery and observe it to see if the bearings have gone out or something as well.
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Unread 11-20-2012, 02:09 PM   #13
Zew
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Quote:
Originally Posted by Marcos View Post
Just a follow up, anything mechanically wrong with the fan will cause it to draw more current, which can be felt as vibration when the load on the alternator and engine increases. Or the Alternator could be bad (you stated a 90a was put in there, but 5.9's came stock with 150a) which could also manifest as greater load and vibration.

Different frequencies of vibration will cause different, seemingly unconnected parts of the vehicle to vibrate if the right harmonics are achieved. Hard to know exactly what the chirping noise you're hearing is.
Ah... for some reason I thought the stock alt was 90 amp. My bad. Sorry bout that one. The chirping "cheeeeeeeep" noise comes from the passenger kick panel... like where the fuses are. As soon as the fan starts you hear a faint "cheeeeeeeeeeeeep" come from down there then the high speed fan kicks on.

I just replaced the battery with a yellow top optima because I wasn't sure how old the battery was that's in the vehicle. I bought this 5.9 just over 2 years ago.

Well ****... I'm bummed. The only reason I bought the 136amp was because i thought i was doing better than stock. crap. In fact i've moved backwards.
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1998 Wrangler Sport w/ 5.2L 318 Swap

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My V8 swap thread: http://www.jeepforum.com/forum/showthread.php?t=618350
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Unread 11-20-2012, 02:14 PM   #14
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Of course... I find this now... http://www.quadratec.com/products/55100_0014.htm
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1998 Grand Cherokee 5.9 Limited - Kolak Ignition upgrade, K&N CAI, DT Headers w 3" Kolak exhaust/Flowmaster 50/Magnaflow CAT, Front/Rear Baer Drilled/Slotted Rotors, Front/Rear EBC Greenstuff Pads, Alpine CD/MP3/iPod Control Deck, RF 6.5 Power Series Separates

My V8 swap thread: http://www.jeepforum.com/forum/showthread.php?t=618350
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Unread 11-20-2012, 02:21 PM   #15
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and 10.00 cheaper... http://www.jeep4x4center.com/alternator-56041394aa.html
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1998 Grand Cherokee 5.9 Limited - Kolak Ignition upgrade, K&N CAI, DT Headers w 3" Kolak exhaust/Flowmaster 50/Magnaflow CAT, Front/Rear Baer Drilled/Slotted Rotors, Front/Rear EBC Greenstuff Pads, Alpine CD/MP3/iPod Control Deck, RF 6.5 Power Series Separates

My V8 swap thread: http://www.jeepforum.com/forum/showthread.php?t=618350
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