Radiator fan question......

[SteveBCloud9]

O.K. I started up my snake this morning and the radiator fan went on. I know for a fact that the fan normally doesn't come on until the needle hits the line just after the 3 lines above the 190 mark on the Tempreature guage. The engine was ice cold and it's about 50 degrees outside. Anyone know why it went on? Do I have an error code? Open switch? The car is a 96'GTS with it's original fan unit. I may upgrade to the 99' unit someday but want to find the reason why it's going on at start-up.

 

[TacDoc]

Was the defroster or A/C on by chance?

Greg
96 RT
00 GTS

 

[SteveBCloud9]

Interesting, if the a/c is on, the fan runs 24/7? I just sent the snake on it's way again so I'll have to look to see if it does it tomorrow.

 

[JonB]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by steveb:
Interesting, if the a/c is on, the fan runs 24/7 <HR></BLOCKQUOTE>

Yes. When engine nears overheat,, normally you turn OFF the A/C.

But on a Viper, the radiator fan runs constantly when A/C is on.

This is one reason the 1996.6 - 1998.9 radiator fans conk out! They run too much, draw too much current....and can even cause a short in the relay or burn out a VERY expensive harness. For these reasons, along with moving WAY more air with less current draw, I urge 96.6 - 98.9 owners (and even Gen1) to upgrade to the latest fan/shroud/motor, suld as a complete module. Simple retro-fit. $159 from PartsRack, THANKS!

 

[Sean Roe]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by JonB - PartsRack:
[B.......This is one reason the 1996.6 - 1998.9 radiator fans conk out! They run too much, draw too much current....and can even cause a short in the relay or burn out a VERY expensive harness. For these reasons, along with moving WAY more air with less current draw, I urge 96.6 - 98.9 owners (and even Gen1) to upgrade to the latest fan/shroud/motor, suld as a complete module. Simple retro-fit. $159 from PartsRack, THANKS!
[/B]<HR></BLOCKQUOTE>

So, um Jon, are you saying that the earlier small fans draw more current than the newer large fans? How much more did the earlier ones draw and what are the actual physical differences between the two fans?

Thanks,

 

[JonB]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Sean Roe:
So, um Jon, are you saying that the earlier small fans draw more current than the newer large fans? How much more did the earlier ones draw and what are the actual physical differences between the two fans? <HR></BLOCKQUOTE>

A guy who sells an always-on-fan doohickey must already KNOW this stuff, but here goes my version to humor you:

1) Yes, the smaller Gen-II single fan and especially the twin-fans of many Gen-1s, draws more current than the 1998.9+ single fan motor. {From running longer/faster? See my personal condensed-smoke-particle beliefs on electricty elsewhere......}

2) Since when the A/C is on, they never shut off, {running more hours and using more electricity in the process} the motors can and do burn out prematurely...sometimes with harness / relay damage. The newer, larger fan runs a SHORTER time, but moves more air for the physical reasons below, and also uses less total current in the process. [ A miracle happens!]

3) I do not know the differences in current draw/hr, but there are fewer minutes running time each cycle, due to moving more air in less time, cooling the radiator/coolant faster. (I bet you can easily check the draw numbers for your fan-switch troubleshooting?)

4) The physical differences you requested:

--1999 shroud opening is larger and more efficient;
--Fan is much larger and has blades of a different pitch;
--Different fan motor, draws less current !!!
--Shroud mounts with 1 fewer stud.
--The dual-fan pigtails and the single are NOT compatible, due to pin vs blade connectors...can be re-wired easily.
--From memory: the duals are 11" and 12" with the Rt side smaller....the single early is 13" and the single 1999+ is 15" or 16". [IF I had time on a Sunday nite to check the warehouse, I could give you the exact measurements, but this is close. Come to think of it, the blade count on the fan may even be different!]

The ANSWER to Steve remains: BUY THE LARGER FAN FOR LOTS OF GOOD REASONS....THEN BUY A ROE FAN KIT TO MAKE SURE IT WONT HEAT-SOAK AFTERWARDS. Bonus: Running the CHEAP NEW fan a lot extra is better than running the EXPENSIVE fan motors a lot extra! Since the new motor cools faster, it draws less current, an won't drain the battery as fast.........

 

[Rich Carlson]

Boy, I feel like the net at a tennis court watching the ball flying over my head going from the East coast to the West coast. The way I remember it is as follows: 92-93 vehicles have a twin fan setup for cooling only...no factory A/C yet. These where single speed fans.

From 94 until early 98, the Viper uses a single fan that is off set to the drivers side on the radiator. This is controlled by a relay, so you get a high and low speed based on the needs of cooling system or the A/C. This fan is on a 40 amp circuit.

From 98 until the present, the Viper got a new fan module that is centered on the radiator, extra blades and little larger to move more air. It is controlled the same way but is on a 50 amp circuit.

NEXT SERVE

 

[TacDoc]

JonB, I remember something about the first K&N cold air housings pressing too ******* the fan shrouds, I guess since mine does not I must have the revised box. Any idea if the revised box might press on the new shroud, I am interested in the upgrade.


96 RT (K&N carbon fiber airbox, smooth tubes, Borla 3" exhaust, revalved Konis, Eibach springs, adj endlinks, anti-toe brackets)
00 GTS (stock but not for long)

 

[Sean Roe]

(At low speed) The single fan setup used prior to '99 draws 25 amps at startup and 13 amps while operating. The newer fan with the larger blades draws 52 amps at startup and 24 amps while operating.
The factory fan wire size is 12 gauge and the newer fan amperage draw can put a strain on it.
Did your '96 have the larger fan on it when it (I think I read, not 100% sure) melted that part of the wiring harness?
Also, I'd have to double check, but I think the electric motors were the same, though the fan blades and shroud were different.

 

[Vip-RT10]

I understand what JonB is saying....that pitch, motor size, frequency, and time are all added in the equation to see how much total draw is, and in the long run, it should drain less. This is common knowledge with electric motors and their loads. Takes more electricity to start and less to run. As far as actual #'s for the draw...hell if I know.

 

[SteveBCloud9]

My A/C, defrost WAS on. Go figure......

 

[Sean Roe]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Alan M 98 GTS NY:
hmmm. Sounds like that the new fan which I installed would need larger fuses or maybe spare fuses and relays (stock ratings of course)for the significant increase in circuit demand for that eventful moment of failure at the most undesirable time or location. How about it Sean or Jon. Are we riding on the edge now?

<HR></BLOCKQUOTE>

Alan,
I edited my post above stating the fan amperage draws to specify that those #'s are at low speed. High speed would be a much higher draw, but we only tap into the low speed circuit with our fan kit, so that's what I know for sure.
Here's some more info: The stock fan wire size is 12 gauge from the fuse/relay box to the fan, there is a low speed and a high speed wire (dark green and light green respectively and Dodge uses a 50 amp fuse for the fan. If you tap our fan kit into the high speed circuit (as one did), the 12 gauge wire "can" overheat and melt the insulation before it blows a fuse. In our fan kits, we use the SAE specification 12 gauge wire, but with a 40 amp fuse instead.