[JonnyB]

My car has a aluminum radiator with 15 inch derale fan and when the fan kicks in you can watch the volt meter drop. Now its not bad during the day but at night with the lights on the volt meter is hovering above the red line when at a stop. I have stock pulleys and my radio is off. The only other accessory is a 5 inch tach mounted on the dash.

By the way my alt. is 135 amp external regulated. Is the damn fan supposed to suck up that much juice or what the hell is goin on here?

[GoodOleBoyzRacin]

somethins definetely up. how do you have the fan wired up?

[chriswao]

sounds like you got like a direct ground or somthing man

[acrbill]

subscribed because I have the same issue. I just bought the car so God only knows how it was wired.

[JonnyB]

I can't remember how it's wired, it was on the car when I bought it. I finally got the internet back and was hoping to have some possible solutions when I get my car back out of storage, fucking North Dakota winters! What possible problems should I look for when checking the wiring?

[superbean]

It should be wired to a relay. How the fan is turned on is up to you whether it be a flip switch or thermostat.

here is a wiring diagram i drew up for a fuel pump setup, but it's the same thing, just fan in place of fuel pump.

This one has a 12v switched power up the relay, or you can run power to a constant hot and have the ground control the switch either by flip switch or thermostat.

[nolife]

We have NO idea what type or gauge of alternator wiring, fuses, etc that you have so there is no single piece of advice to go with.
Assuming you have adequate alternator wiring (not some small or coroded alt wires), and the fan wiring is good... I would get the battery checked first. When you see large changes in voltage from loads, it usually is a sign that the battery is weak or your terminals are corroded. The alternator puts about about 13.5 volts when the car is running. As load increases, the voltage drops. The voltage should only drop to just about the voltage of the battery which should be at least 12v. If your battery is less then 12.0-12.5 because it is weak or your wires and terminals are corroded, you will see larger swings in battery voltage as the load increases. With nothing else on, but the car running, does your emergency flashers cause the battery volt meter to jump around at all?

[JonnyB]

Not sure if the volt meter jumps with the emergancy flashers but whenever I roll one of the windows up or down the volt meter drops. And that is with the fan off. Battery is not that old but I think it was a cheap one.

[nolife]

Well volt meter fluctuations are normal but a bigger change would indicate a problem. You would have to be familiar enough to now what is normal and what is not for your car

Cheap battery or not, it should still meet the demands.
Can you get back to us with what your battery voltage is with the car off and with the car running? You also stated you have an external voltage regulator instead of an internal one which is the stock setup. With that, I assume there were some wiring changes so things are a little different.

[JonnyB]

Damn me and my short term memory! My dad and I checked that last summer the only thing I remember was with the car running and fan on we were getting mid to uper 11volts and im pretty sure it dropped to 10 volts with the headlights on. My car is stored out of town but if I have the time this weekend I can go check again.

It has an external volt regulator because it is an SSP or someone modified it to be a SSP clone, unfortunatly without the dog tags (which I dont have) that are supposed to be attached to the radiator brackets there is no real proof if its a real SSP or not.

[JonnyB]

So after work I was having a few beers with my boss's friend tellin him bout my problem and he suggested I get a flex fan that bolts onto my water pump. Would that be a good alternative to the electric fan I have now? My main concern is if it would cool my aluminum radiator good enouph, plus I've never heard of them before and know nothing about them. What do you think?

[**Chris**]

I had a charging issue when I went with a Lincoln Mark VIII fan.... the issue was solved with a simple alternator pulley change to a smaller diameter.

Smaller alt. pulley = more rpm's of said alternator = higher charging output. Pulley was like $20 or less.

The Mark VIII fan is one of the cheapest, most efficient cooling fans you can buy used but it also draws the most current. Try the pulley change before you do other things, it's cheap and easy.

[flyin ryan]

Originally Posted by JonnyB So after work I was having a few beers with my boss's friend tellin him bout my problem and he suggested I get a flex fan that bolts onto my water pump. Would that be a good alternative to the electric fan I have now? My main concern is if it would cool my aluminum radiator good enouph, plus I've never heard of them before and know nothing about them. What do you think?

flex fans suck balls don't do it.. there's a reason why there $30 or $40 new and besides that there loud as hell too might as well pickup a stock fan/clutch and shroud from a junkyard if your going to concider a flex fan especially if it's a street driven daily driver.

flex fans were big back in the say when electric fans weren't around to choose from

[nolife]

Originally Posted by flyin ryan flex fans suck balls don't do it.. there's a reason why there $30 or $40 new and besides that there loud as hell too might as well pickup a stock fan/clutch and shroud from a junkyard if your going to concider a flex fan especially if it's a street driven daily driver. flex fans were big back in the say when electric fans weren't around to choose from

I wondered why I never see anyone with a flex fan. It makes sense though. They would be a good choice compared to a metal fan directly attached to a shaft but a bad choice compared to a clutch fan.

[JonnyB]

Hey Chris what size alt. pulley did you put on your car? Thanks for all your input so far guys, it really sucks not driving my car at night for fear of killing the battery. This saturday I'm going to make way down to were I have my car stored with a load tester and a volt meter and I'm going to try several tests and I will post the results hopefully saturday night.

[mustangsoldier]

i have the same issues only b/c i still have the 75 amp alt. but im about to pick up a pa performance 130amp alt from latemodelresto

[JonnyB]

Ok just got back from load testing my car and this is what i found. When I got there the battery was dead so I used a jump box to start it. With the car running and nothing else on the emergency flashers did cause the volt meter to drop. Heres the numbers from load testing it.

Car running nothing on mid 13

Fan on jumped around in the low 13 high 12 range

Fan and headlights jumped around the mid 10 to high 11 range

I was also going to use a volt meter to try and determine if there was a bad ground but the battery completly died, couldn't even start it using the jump box. Btw the charge wire coming of the back of the alt is about a 8 or 10 gauge wire. Battery posts had very slight corrosion.

[JonnyB]

VICTORY IS MINE!!! Sorry i had to dig up this thread cause i fanaly got this problem taken care of. Turns out even though my alternator tested out fine it just wasnt capable of producing enouph amps at idle to keep up with everything so i bought this one and have no more problems.

Tuff Stuff 7069FBULL6G - Tuff Stuff Silver Bullet Alternators

[1989Gt.]

i have a 100amp alt and my volt meter drops. and i have one sub in the back with two amps.... so thats why but impretty sure its normal unless its in the red cause notic that when your driving it should be at about half way when your idoling it prob fluxuates

[1slo5.0]

Originally Posted by JonnyB VICTORY IS MINE!!! Sorry i had to dig up this thread cause i fanaly got this problem taken care of. Turns out even though my alternator tested out fine it just wasnt capable of producing enouph amps at idle to keep up with everything so i bought this one and have no more problems. Tuff Stuff 7069FBULL6G - Tuff Stuff Silver Bullet Alternators

Was your alternator a 3G? If so, what was used for a supply wire to the solenoid? The original black and orange power wires?