Rennlist - Porsche Discussion Forums - Better heat for winter time?

Rennlist - Porsche Discussion Forums (https://rennlist.com/forums/)

- 911 Forum (https://rennlist.com/forums/911-forum-56/)

- - Better heat for winter time? (https://rennlist.com/forums/911-forum/659693-better-heat-for-winter-time.html)

Better heat for winter time?

Don't get me wrong... when I get heat it's HOT. When I first got the car my heat sucked, HORRIBLY. Found out many of my hoses were split. So I'd get a hint of heat... now I get some.. but I've read some people say "Oh it just about roasts me out of the car!" - I don't get that at all. It's warm, but when it hits 0F outside I think I'm gonna be freezing my balls off if I don't get a little more heat.

I've replaced all my hoses, even the hoses to the heat exchangers while I had the engine out.

I also re-adjusted the flaps with the help of my friend when the engine was out. So the flaps open and close fine, new hoses, everything is good. I cleaned out the blower. But it just feels like the air flow isn't all that strong. My issue is that last winter in the snow the defrost did not work well. Granted I had almost NO heat then, this time I do have some.

But am I missing something? Now I think mine has those flapper boxes in the front of the car too, is it worth trying to pull the assembly apart up front and check that?

Also, it seems like when I adjust the levers on the dash that they are hard to move, lots of resistance. My 914 is not like this. My guess is that perhaps the boxes aren't opening 100% of the way and maybe that's restricting some of the flow?

I also have read about this backdate - but I guess I still don't get how the backdate works. Is it more efficient? Or is it just for weight savings? It looks like air is blown from the fan to the blower and blown back through the system. The backdate uses individual hoses from the fan to the exchangers and is either just dumped out the flappers or isn't - but isn't it already with the exception of the blower? I basically just want to make sure the system is efficient.

Interesting. I'll be following this thread. I've never had a problem with heat in my car. When I turn those switches on high, the only way it could get any hotter is to light the car on fire. It actually gets so hot that my nose dries out on the inside!

The levers on my control box move very easily. I'd check the dash mounted control box as well as the travel of the rods connected to the flapper that directs air to the defrost/dash vents.

When I first bought my car none of the fans worked (engine compartment or both footwell blowers) and it still got awful hot just by raising the levers...even warm to drive in cool weather with the top down.

Once I got the engine compartment blower and both footwell blowers working it was nuclear hot. I have some minor restriction on defrost heat coming out of one of the four windshield vent orifices due to a PO running stereo and alarm wire through the ducting from the cabin to the frunk but it works fine especially when combined with some a/c blowing dry air.

Good luck...

Quote:

Originally Posted by CorsePerVita (Post 8941746)

If you open the fan/blower in the engine compartment you will find a design flaw. The squirrel cage blower wheel is displaced from the face of the air intake path. This was done so that when the engine RPM is high enough to force airflow it can bypass the blower wheel.

I modified the one in our '78 so that ALL engine fan forced air MUST pass through the blower wheel, no bypass/leakage path.

Other than lowering the windows and moving LOTS of FRESH (COLD!!) airflow through the cabin in the '78 I have NEVER found a way to keep the windshield defogged on a true winter day in our area of the country. The additional airflow "boost" fans in our '88 seem to truly make a difference.

Are your footwell blowers working?

Corse... Are we to guess what year your car is? Different models require different tactics. If it's an 84-89 Carrera, it's probably the footwell blowers or the fuses for them located on the housing under the kick panels.

Sorry Ron, for some reason I thought I had posted that info. I was pretty tired when I posted it.

It's an 82' 911 SC 3.0

I am not entirely sure if it has footwell blowers or not. I don't hear anything turn on in the front of the car although I can feel the blower turn on if I pop the engine lid with the levers up.

For clarification it isn't the center flapper levers floorside that are sticky, those work great. It's the levers on the dash itself that are rough to push left to right or vice versa.

Pavegeno928: good point on the travel on the levers. It sort of feels like it has a lot of resistance so maybe it isn't opening all the way in the front? I'll tear it apart tomorrow and look at it and also lube up the moving parts and see if it helps.

Okay first off the issue isnt really the heat , the issue is the distribution . you wont have footwell blowers so you may find your feet roast but the rest of you is cool . i dont drive mine in winter routinely but i have had it out on some cold days and it is acceptable.

make sure your exchangers arent rusted out or leaking or you will bleed heat out there .

Also what you are having trouble with are the bowden cables. it takes an hour to take the heater box out if you dont have AC then you can closely check the flappers and the bowden cables ,, replace if necesary.
there is no forced air system for heat in these cars if you dont have foot well blowers . The fan at the front is for fresh air only.

The blower in the back is only for when the car is at idle and is weak at best and may defrost a little but will not do very well to heat the car at all if you are in bumper to bumper taffic at -30C . this is for two reasons. 1. The engine is at idle so the fan wont be running fast enough push the air through .. and 2. the car is at idle and not much heat is being generated . What is being generated is being conducted away by metal exchangers facing the elements.

However at road speed there should be enough heat and rpms to push the heat into your cabin. On really cold days i have gone down a gear on some roads as this increases RPMs for heat, and higher rpms also make the fan spin faster to push the heat in ..

so once again it may come down to " how you drive it " .. good luck ..

PS the Targa roof isnt helping either ... :)

I have an 85 911 with AC and find hea t is good but defrost only clears the passenger side. I assume this is the duct for the driver side but any pics of what the ductwork should look like for condition and routing? Also, what year did fool well blowers start? I may need to check fuses here as I don't think mine run. Thanks

Billm, I'm not sure when footwell blowers started, but I do know they are in the 85-89 Carrera's. Also check your fuses. Remove the kick panels (top left & top right foot area) and you'll see them. They are in the harness for the blowers. Most folks know where they are because they squeal like heck. If the fuses are blown an you put in new ones, you may find the motor bushings might squeal. If they do , you can buy new motors or like i did, disassemble far enough to lubricate and put them back in.

I have a 79 911SC Euro and sometimes my feet feel like they 're on fire. I have no idea why I'm generating heat as everything is off. Recently I stuffed the foot well vents with wash clothes to stop the air flow. The hot air is not constant but when its hot, its really HOT! Any suggestions are appreciated.

Thanks ronmacatee, I will check that out for sure.

Quote:

Originally Posted by Andy Kay (Post 8947270)

get underneath and make sure your cables are opening and closing your heater boxes . My guess is they are sieized in place or the cables and springs are malfunctioining