Total Nightmare

[Black Sun 5.0]

I had an S/N 95 fan installed in my '91 Stang about 3 months ago. I'm driving to work today, and I suddenly smell something burning (electrical). Next thing I know, the temp is maxed, and now I have a blown head gasket. Apparently, it looks like the fan had a meltdown. Anyone else ever see this? Are these things warranteed? Also, what kind of damage could I be looking at from the head gasket? I had boil over and the coolant looks like chocolate milk. Oh, it's a REAL BAD DAY TODAY.

 

[mustangsquared]

Sorry to hear to hear about the engine. I would think warped heads, maybe a bearing or tow...I would do a complete rebuild....just to be safe. No idea how much coolant got in the oil and into the pump and other areas. Of course with all your mods going to a 306 or 331 would be nice. Still sorry to hear \she dumped on you.

 

[Black Sun 5.0]

Well, the heads may be fine, they're cast iron. But the question at this point is now irrelevent, I already talked to Mustang Magic and they're gonna drop a new 302 w/forged pistons in. Oh, I'm gonna put a cam in too. I figure I may as well take a negative and make it a plus. I just need to find the $$$$$. But it will get done, oh, it will.

 

[Michael Yount]

Sorry about that - at least you'll get to make it better. Sounds like you may need to reconsider your wiring/controls for you fan. This unit is the best - and there's an optional LED available that goes inside the car so you know what the fan is (or isn't) doing. www.dccontrol.com

 

[Black Sun 5.0]

I've seen that unit, I should look into it. My question is, though, what could have possibly caused the S/N 95 fan to die on me after 3 months? Thing went snap, crackle and pop. It's hooked up to 2 big relays, and I control high and low with a switch in the car. I didn't do the install, but I assume that is the correct setup. Fan is expensive, too.

 

[OrLackThereof]

Sorry about your luck dude..I know how that goes. My electric took a ***** when I was on the interstate. Got off, temp shot up so I pulled it over as quick as I could. Never maxed the gauge out, but she got up to about 250 or so...enough to have a major coolant boilover, but thats it. I popped the hood and looked at the wiring and namely, the FUSE PACK. Which was MELTED SHUT, the fuse and all. I went to a Flexfan afterwards. Out of blind fear.

This is kinda freaky, you're like my twin. One bad foglight, electric fan problems, 91 GT, Non-original motor.... Crazy world...

 

[Black Sun 5.0]

Was it an SN/95 fan? I'm just curious.

 

[OrLackThereof]

Not unless SN95's came stock with a Bosch 8-blade

 

[baskin]

Are you using the Rf43 (F5ZZ8C607A) ? If so, applying power to both low and high speeds simultaneously will burn out the motor. Switching directly to high from off will eventually do the same on all of the two speed fans. How much did you pay for the fan?

 

[HISSIN50]

as i recall, there was a recall or TSB on the SN fans - the fix was to put a circuit breaker in the wiring. i think the motors are prone to internal failure and the CB helped save harnesses. the SN guys know for sure, but i think im right.

good luck.

 

[baskin]

Do a search and you’ll find that there's a correlation with the infamous fan switch mod and the '95 failures for the same reason stated above. You’ll also find that the Ford techs disable the switch and the ability of the CCRM to respond to it when they do the repair. The sn95 fan uses the same motor as the Taurus Fan.

 

[Michael Yount]

....and another good reason to simply use the Delta Current controller to run the fan -- takes care of all that and more.

 

[Black Sun 5.0]

Ok, so what everyone appears to be saying here is that using a high/low switch for the SN/95 fan is a big nono? How tough is it to hook up the Delta Current control? I already have everything wired through 2 relays (sorry, I know nothing about electrical work), I guess for the high and low switch. Also, which controller do I get for my fan?

 

[Michael Yount]

Hooking up the DC controller is MUCH easier than hooking up switches and relays - the temp. probe literally plugs into the controller; there are only 3 wiring connections to make - hot from the battery, hot to the fans, and ground. Instructions come with it, and you can read/download them from the site. Search around the site and you'll see them - they couldn't be more idiot-proof. Uh, that wasn't aimed at you.

 

[Black Sun 5.0]

Being that it is a 2 speed fan, does the controller itself work that way or do I just hook it up to the high speed connector? Also, back to my previous post, which model do I get? I know that there is a 60 amp, 80 amp, etc. Better way to ask that, does anyone know how many amps an S/N 95 fan draws?

 

[Michael Yount]

Contact Brian Baskin at Delta - he'll coach you on the best selections. He knows his stuff. I'm guessing he's gonna tell you that you simply hook the output of the controller to the high speed connection of the fan; that way if the controller determines that 100% fan speed is needed, it'll have it available. You'll ignore the low speed connection if you're using a variable speed controller. Brian can also tell you which controller to buy depending on the fan you select. Most can be handled by the smaller 35A controller; but the big MkVIII huffer needs the 60 I think.

 

[Michael Yount]

I believe the SN95 and the Taurus 3.8L fan share the same motor. I believe this unit also powers the fan in a Volvo 940 turbo - which may be a model you can score a reasonably priced used unit from in the junkyard.

 

[xxxCadillacxxx]

I am currently running a modified VW fan shroud (because it fit my FMS 3 row) with custom brackets and a Single SN95 fan installed. I have 1 (yes 1) relay that i took off of the computer of a junk car triggered by a thermister i soldered into the heater coolant line. I have never had any kind of overheating problem with this setup. You dont really need 2 fans blowing 1500000 cfm each to cool your car, just make sure your shroud is pulling all of the air through the rad.

You can get all of the parts i used from a junkyard for about $50......

 

[baskin]

One fan on one car with a few thousand miles of use doesn't prove or even indicate reliability.

 

[Michael Yount]

You beat me to the punch Baskin. Cadillac - your SN95 fan probably pulls more cfm than my dual set up does - so you likely win the million cfm contest. The MKVIII single pulls WAY more air than my dual set up does. You're correct - an effective shroud significantly helps make the most of the fan you have.

But the real issue in this post doesn't even have anything to do with fan capacity. This guys fan (just like yours) was cooling his just fine - but he had a butchered control/wiring system. You can trigger these units with switches (thermal or otherwise) and relays - but that's such an antiquated way to do it. There's a big current surge on start up when the relay triggers the fan wide open - 2 to 3 times the operating current requirement hits the system. That's hard on the battery, hard on the alternator and hard on the fan motor. Cycling the fan on and off at 100% speed also has the engine operating temp yo-yo-ing around the thermal switch's settings. The variable current set up holds the engine temp to +/- 3F and totally eliminates start up spikes which results in longer component life - alt/battery/fan motor. Best of all, it only uses the fan as hard as it needs to in order to keep the engine at the set point - which by the way you can easily alter from time to time if climate or a geographic move dictate. I operated my system with relays and thermal switches - but no more. There are MUCH better mousetraps available.