Printable Version of Topic

Posted by: Morrie Feb 19 2018, 05:47 PM

My car- 76 914 2.0 with D-Jet, essentially stock heater, with SSI HE backdate to remove the emissions stuff and an extractor style muffler/exhaust.

I've got the single outlet engine bay heater fan installed and functioning electrically, but I am on my second used one and this one has bad bearings too. Not fun.

What I am wondering is if anyone has tried deleting the electric fan from the duct system and just running with the engine fan? I did this on my 76 912E running a set of 411 heat exchangers and had decent success.

This is common on the 911s and 912Es, but this is a different setup entirely and I do not want to assume anything. I know it will work theoretically, but wanted to know if anyone has actually done this and if the airflow is sufficient for driving in warmer climates. Right now the coldest I would likely see would be around 30 degrees. I know that the ariflow is reduced... that it changes with engine speed, etc....

The other option is to rebush the fan. I looked at it and you can see the wear in the bearing on the end nearest the fan impeller on both which allows the impeller to rub on the housing. Has anyone done a successful DIY repair, or found a suitable functional replacement?

Posted by: mark04usa Feb 19 2018, 06:00 PM

The heater fan in my '70 1.7 has not worked for years...the motor still runs, but the fan impellor sheared off. The heater still works well enough for most of our Texas winter days. The fan only comes on at the max heat position anyway, so you can just unplug the electrical connector to the fan and leave it in place. No need to remove or duct past it.

Posted by: Morrie Feb 19 2018, 06:10 PM

Thanks Mark. Appreciate the help. I'll go unplug the fan connector and see how it goes.
And yes, another beer is in order.

Posted by: saigon71 Feb 19 2018, 09:40 PM

The stock heating system works well without a fan.

Defrosting is a different story. I've been caught in a quite a few bad rainstorms. The windows fog up badly. The engine fan can keep up with defrosting the front windshield while RPM's are up, but the fan is necessary in stop & go traffic so you can see.

Posted by: Morrie Feb 20 2018, 10:02 AM

THAT is a very good point. I would hope to supplement with the cowl vent fan / fresh air but agree that could be a problem. I think I will put some of that RainX "fogX" product on the glass.

My other car is a 68 912. Those never had any kind of fan, cowl or engine bay, so you are strictly at the mercy of the movement of air into the cowl or off the engine. I guess if I manage this the same way I can get by.

Thanks for the tip though, you probably saved me from the first rainstorm.

Posted by: rhodyguy Feb 20 2018, 10:39 AM

Pick up a couple of rubber caps and clamps at the hardware store and cap the j tubes. You'll be suprised at the heat output without the fan.

Posted by: mepstein Feb 20 2018, 11:04 AM

Bob dd's his 914 so he knows what works and what doesn't. I've never had a working fan. Plenty of heat.

Posted by: BeatNavy Feb 20 2018, 11:29 AM

I've driven the last two winters without a fan, including in single digit temps. It's not garaged currently ( ) so that includes defrosting it on those chilly mornings. Certainly gotta use the scraper, but then the engine fan is good enough, esp. after a couple of minutes of driving. It may not be as cozy as my "other" DD with heated seats, heated steering wheel, and the other nonsense, but even without the aux fan it was plenty warm.

Posted by: BeatNavy Feb 20 2018, 11:31 AM

Oh yeah, and this Good idea to cap to keep warm air from the HE's out of the engine bay if you delete the fan/hoses.

Posted by: Morrie Feb 20 2018, 05:26 PM

Heater fan removed, along with the associated hoses. More room to work in the engine bay is always good.

Bought a pair of 2" rubber plumbing caps and installed on the ends of the ducts where they enter the engine compartment, and installed new tube to tin seals.

Now if the weather here dries up a little I will take it out and see how it works. I expect it will be just fine. Thanks guys!