Rear Heater Blower Fan opinions in 2019 A.D.?

monkeyodeath · 11-11-2019, 09:20 PM

So I've spent the past 2 hours researching the dreaded rear heater blower fan/reed switch issues on the 3.2 cars.

Lots of threads, many of them now quite old. So I thought I'd try to get some more current opinions.

My heater blower (the one in the engine compartment) seized and died for the second time. The first time, I replaced the brushes and bored out the stupid metal bushing for a needle bearing. But now it's dead again (12v to the pigtail, so I know it's the fan).

I'm considering just doing the fan delete (i.e., the half-ass "backdate") -- cheaper than buying a replacement fan, better engine access, and I've yet to find a thread where someone who did it complained about inadequate heat.

Some questions for 2019:

1) I know that the 3.2 cars will kick on the heater blower if the car is idling and absolutely blazing hot. Is there any consensus as to whether this feature is actually effective for those of us who don't do gridlock in Dubai or Mumbai? Am I putting my engine in danger by getting rid of it?

2) There was also some suspicion that part of the reed switch is a safety mechanism to keep the footwell blowers from pulling exhaust fumes into the cabin. Are we still worried about this?

3) Has anyone experimented with an alternative (read: cheap) replacement motor? There was the Grainger motor mod from like 10+ years ago, but haven't seen anything more recent. Not really my preferred route of action, but curious if anyone's tried anything.

carreradpt · carreradpt's Garage

My 2 cents

I have Autoheat, no handles. My situation was my heater fan had stopped at some point. I still had some heat by rotating my dial and the cabin would warm. Just no forced heat.

I live in FL and use the AC a lot. My temps never rise much above the 2nd hash mark (90c). I also installed a fan on my oil cooler with a manual switch. Even though the fan was inop my temps were controlled easily. I have since fixed my fan.

Can't speak to the #2 above, though I have read the concerns about the negative pressure and allowing fumes into the cabin.

chuckr · 11-12-2019, 07:14 AM

I removed my blower motor years ago. Doesn’t get that cold here in north Louisiana.
The heater has no problem at all heating up the car without the blower. I also removed the heater blower assist motors in the foot wells.

gomezoneill · gomezoneill's Garage

I believe I have a blower if you're interested.

Jack Stands · Jack Stands's Garage

I haven’t noticed any significant improvement between my ‘84 Targa’s heat output over my old ‘75 Targa ( that was converted to SSI heat exchangers). I think getting rid of the three blowers (engine and two footwell) doesn’t cause any significant decrease in heater output. If you need more heat, shift down a gear!

mnez · 11-12-2019, 10:24 AM

I've never understood #1 - all you are cooling is the exhaust pipes inside the heat exchangers. So no concerns there for me.

#2. I deleted the engine bay heater blower years ago when backdated my 3.2 to SSI's but kept the footwell blowers, and also did the relay modification to allow the footwell blowers to operate. Pulling exhaust into the cabin hasn't been a problem, and if you were worried, simply turn off the blowers while idling. Heat is still more than sufficient.

#3. Never considered it.

MichaelSJackson · 11-13-2019, 11:52 AM

I have a sunroof car. If I crack it open about an inch, while moving, the vacuum created over the roof will suck the heat more than you'd believe. More than twice I've surprised my passenger by opening the sun roof in a snow storm. (Sorry not only do I have a sunroof, but I drive in the winter; not to mention the rain.) Just as they are turning to me to ask what I'm doing, you can see them feel the sudden surge of heat. I just close the roof, if I have to stop for a street light.

Once I removed the fan, I retro-fit the old tin that directs the engine fan air to the left heater box. Much cleaner look too.

monkeyodeath · 11-16-2019, 08:52 PM

Quote:

Originally Posted by mnez

I've never understood #1 - all you are cooling is the exhaust pipes inside the heat exchangers. So no concerns there for me.

I think the idea is that the exhaust header is the hottest part of the engine and its heat rises up into the cylinder heads (since the heat exchanger is directly below the cylinder head). So if you can cool off the exhaust manifolds, it helps cool the engine.

I think the 964 and 993 engines had something similar that activated much more frequently.

monkeyodeath · 09:18 PM

So I decided to delete my heater fan. Tired of fixing it. The stock fan output shaft runs through a dry metal bushing (no bearing), which eventually wears egg-shaped and causes binding and squealing issues. Plus sitting in a hot engine compartment probably doesn't help it live any longer.

I got the left-hand duct piece from Pelican and used a little SCAT tubing to hook it into the crossover pipe. Tight fit, but doable. Didn't need any reducers, was able to just shove the 2.5" hose into the rubber coupling at the top of the crossover pipe.

Parts cost probably wasn't too much cheaper than just getting a replacement fan, but at least now I don't have any more fans or $400 weirdo relays to worry about. Seems like I've had to fix something with the heater system every time the weather changes and I want to use it again.

Also, I'm not typically someone who cares all that much about underhood appearance, but I'm sure I'll appreciate having all the heater fan stuff gone the next time I do a valve adjustment. It does also look a lot nicer in there without the big plastic ducting in the way.

Also found that the stupid heater control relay was malfunctioning, again (sticky footwell blower relay). So I gutted it with a dremel and put a normal relay in the box.

Haven't had time to see how the heat feels now, but I'm pretty sure it'll be fine -- barely ever used it before, and found that it was pretty much shoe-melting strength when I did.

Not super-worried about the exhaust fume issue...might just grab a cheap CO detector and throw it into the glove compartment.

The only thing that bothers me is losing the potential cooling function of the heater fan when the car is at low speeds or off. Seems like these cars need as much cooling as they can get, and I hate to take any of that capacity away.

That being said, I can't recall a time that cooling function has ever kicked in in years of owning this car (though, to be fair, the fan has probably been broken half of that time).

I suppose down the road I could look into some kind of inline fan that could sit in the ducting. Or just beef up other parts of the oil cooling so that the car never gets so hot that it needs a little electric fan to wheeze onto the headers.