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Hello! I've been searching all morning trying to figure out what these two small fans in front of the radiator are. Just drove home a new-to-me 1987 Firebird (it's a Base model with the TPI 5.0L). It had been off all night and this morning these two fans were still blowing. They are Papst (or PAMOTOR) model 4112 KX blowers. If it helps, the A/C also isn't working, so may potentially be related. Any help identifying what these fans are for and why they might be running with the ignition off would be greatly helpful. Thank you!
Last edited by rampant10; 04-10-2023 at 08:38 AM.
Reason: Papst not Pabst (freudian beer slip)
Re: What Are These Two Small Fans Running Constantly
those fans are not factory. they look like fans you'd see in a desktop computer case. does your car have a large fan on the front of the engine or electric fans with a shroud behind the radiator? if you don't then may be these were added by some idiot previous owner who thought they would cool the radiator?? get those out of there. having them run constantly is going to eventually drain your battery.
Re: What Are These Two Small Fans Running Constantly
Originally Posted by battmann
those fans are not factory. they look like fans you'd see in a desktop computer case. does your car have a large fan on the front of the engine or electric fans with a shroud behind the radiator? if you don't then may be these were added by some idiot previous owner who thought they would cool the radiator?? get those out of there. having them run constantly is going to eventually drain your battery.
Thanks. That's what I was thinking too, since as far as I can tell they don't show up on any wiring diagrams. Curious if anyone else has an opinion on these before I remove them. I may just unplug them for now to save my battery.
Re: What Are These Two Small Fans Running Constantly
They're... 2 small fans. Look like computer power supply parts. Impossible for anything that moves that little air to make any significant contribution to the issue at hand.
As said, DEFINITELY not factory.
I wouldn't be so harsh about "idiot"... could have just been a moron. Or maybe only a person with a really fanciful imagination. "My car used to overheat so I fixed all the leaks and filled it up with water and added these and now it stays cool, can't believe I waited so long to make such a significant mod to my car"
Curious if anyone else has an opinion on these before I remove them.
My opinion would be, not to sound like a jerk or anything, but that YOU'D be the idiot if you DIDN'T remove them immediately.
Re: What Are These Two Small Fans Running Constantly
Thanks for the help folks! Looking forward to hanging on these forums. I'm sure there will be more adventures in "what the hell did the previous moron do".
Re: What Are These Two Small Fans Running Constantly
Welcome. Congratulations on your new Firebird.
Now that the fan mystery has been solved, let's figure out which model Firebird you have, because there's no such thing as a base model Firebird that came from the factory with a TPI engine, so you should probably check the engine code in the VIN.
IF it really looks like a base model, and the 8th digit of the VIN is F (5.0 liter 305 TPI) or 8 (5.7 liter 350 TPI), then you've got a Formula. Otherwise, it's either a Trans Am or GTA and has gfx.
If that digit in the VIN isn't F or 8, but is H (5.0 liter 305 carb), then it could be a base model, a Formula, or a Trans Am. But if it's the V6 code (S?), then it's definitely a base model. In either case, H or S, then the TPI engine isn't original to the car and has been swapped in.
Re: What Are These Two Small Fans Running Constantly
Oh it definitely was converted to the TPI. It was originally the LG4 5.0L 4bbl engine. Both the factory options list in the console and the VIN number confirm it shipped with the 4 barrel carb.
Re: What Are These Two Small Fans Running Constantly
Hilarious! A 120mm case fan might make a difference in a computer, but it's not gonna do anything here other than drain the battery.
Gotta agree with RedLeader, this is among the strangest things I've seen done to a car. It's simply baffling. Might as well have just left one of those fold-out fans in there that old ladies use at theater performances and such, probably would have been just as effective.
Re: What Are These Two Small Fans Running Constantly
Update: it gets even stranger. When I went to remove the "computer" fans, I traced the wiring back to a toggle switch under the steering column that turns the fans on and off. There are a handful of toggle switches under there I just can't WAIT to trace down to other shitty mods...
Potentially related, the engine does seem to run hot when not moving. It's a sunny 82 F Spring day here in North Carolina and the dash gauge was showing about 230 F in stop and go traffic. Dropped back down to about 180 F when moving through fresh air on the highway. This has been typical over my one week of ownership. Does anyone know if that's normal for these vehicles? 230 F feels scary high to me since the gauge redlines at around 260 F. I'll be checking the thermostat when I get some free time to wrench, but curious as to others' experience.
Re: What Are These Two Small Fans Running Constantly
Yeah that's about right. Don't forget also, the factory gauge isn't the most accurate of all fine instruments. As long as the motor seems to be OK, it probably is.
Re: What Are These Two Small Fans Running Constantly
My only guess is someones way to work was often full of traffic jams and hot weather..... so maybe a little bit Circulation with this quiet fans let the noisy fan run less often
You have to admit...these Brakets and wiring are good work . Also these two badboys are original EBM - PAPST Made in Germany, They are top notch. 40 Dollar per Piece.
PAPST builds the proffesional ones for big Servers and industrial Equiptment. These 10 Watt ones already making 100m³ / h airflow per piece and are very quiet.
Maybe they where efficent enough to just keep it under switchig big fan
Re: What Are These Two Small Fans Running Constantly
Originally Posted by rampant10
Potentially related, the engine does seem to run hot when not moving. It's a sunny 82 F Spring day here in North Carolina and the dash gauge was showing about 230 F in stop and go traffic. Dropped back down to about 180 F when moving through fresh air on the highway. This has been typical over my one week of ownership. Does anyone know if that's normal for these vehicles? 230 F feels scary high to me since the gauge redlines at around 260 F. I'll be checking the thermostat when I get some free time to wrench, but curious as to others' experience.
GM made these engines run hot for emissions reasons, not for performance or longevity. You would do well to get your temperatures down to the 190-210 range. What do your fan(s) look like? Are they coming on strong?
There are thermal switches you can get that will turn the fans on sooner, thus lowering your temperatures. There are also fan upgrades, if you are interested.
Re: What Are These Two Small Fans Running Constantly
I agree. After driving some hot days in traffic and seeing that temp around 220 far too often, I've decided to lower the fan turn on temperature. I've poked around the forums and the tech articles (Willie's is great) and read a ton, but I'm still not certain if just replacing the thermostat is enough or if I will need a switch too. Anyone have any advice or useful links to forum threads, articles, or videos that might be helpful?
Re: What Are These Two Small Fans Running Constantly
Lower temperature thermostat will not do anything if the fans aren't moving air through the radiator. I used the (now discontinued) 176 degree Hypertech fan switch with a 180 degree thermostat. My car runs 190-205 when fully warmed up, depending on ambient temperature.
There are other thermostatic switches to choose from, just be sure to get one that actually screws into a coolant port, and not one that sticks into the fins of the radiator.
Re: What Are These Two Small Fans Running Constantly
Originally Posted by rampant10
Oh it definitely was converted to the TPI. It was originally the LG4 5.0L 4bbl engine. Both the factory options list in the console and the VIN number confirm it shipped with the 4 barrel carb.
I hope they did a better job converting it to TPI, than they did deciding to install those fans.
Re: What Are These Two Small Fans Running Constantly
Well, my interpretation of the history of this vehicle was that the engine was immediately converted to TPI to back in '87. Why it wasn't just ordered that way in the first place (especially considering the large amount of all the other upgrade options that were ordered from the factory), the world may never know. Regardless, it has run great during the ~3k miles I've driven it, with the exception of some intermittent belt squeal when the AC is on (I think I need to change out the tensioner). Still does 0-60 in 6.7sec last I checked. She's in great shape: engine compartment is squeaky clean as is the interior and body. There's just some weird quirks like an ancient alarm system, the weird tiny auxiliary fans above, and some nonfunctioning aftermarket fog lights which I have got to figure out how to replace with stock GTA/TA fog lights. Maybe I'll do an intro post at some point with a summary and a bunch of pics in whatever board that's appropriate (probably regional board).
04-10-2023, 08:37 AM
"My car used to overheat so I fixed all the leaks and filled it up with water and added these and now it stays cool, can't believe I waited so long to make such a significant mod to my car"
