Hot feet, need help...

Hi all. I have a couple quick questions for you. Last November I purchased a 74 Carrera. It is my first Porsche. I'm trying to learn all I can, pick up all the books, start slow...

Anyway, I noticed (actually my wife noticed) that the passenger foot area gets quite hot. This seems to happen independent of heat adjustments and only when the car is in motion. Cools down quick after the car is stopped and the ignition is switched off

Proding around a bit I noticed that there is some sort of radiator behind the passenger wood access panel. What is this? Is this where the heat could be coming from? (The car does have AC)I haven't been able to get out and drive with someone feeling around under there yet. This is my next step.. I'm sure it will help pinpoint the location of the problem.

Any help would be appreciated.

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Dan Shust
74 Carrera

I have no idea what the radiator thing under the footboard would be, but my first guess about the excess heat would be that a heater valve (heat exchanger) cable or slide is broken, and the slide is stuck in the open position so your heat is effectively "on" all the time. Look under the car where the heat exchanger slide valve is, and see if it is stuck open even when the heater lever is off.

Good luck,
Chris C.

Chris:

Am I missing something here? There are no radiators under the foot boards on a 1974 911 (which is an air-and oil-cooled car, with external coolers).

Dan:

That "radiator" under the passenger footboard might be an audio amplifier, which has fins for "cooling". I had one installed under that empty space, but it is definitely not a radiator (where would it get cooling air in that position, and what would be attached to that small an item?

Your source of heat might be the oil lines which run from the oil tank on the right rear, under (to the outside of the body) the passenger seat, and thence to an oil cooler in front of the right front wheel. Look under your car on the right side, and see if there are two lines there. One for supply, one for return. Both will be hot to the touch.

With air conditioning, there is an evaporator behind the valence panel in the front, but it is located on center, and would be just as hot for you as for your passenger.

Try feeling around the footwell as you get these complaints, and see where the heat is coming from. Then trace it to its likely source.....Andras

Andras,

The thing under the footboard is definately not an audio amplifier. The fins are very thin, some are bent. Looks like some sort of heat exchanger (I was calling it a radiator but that might have lead to confusion.) If the car was "stock" what would I see in this area? Can't seem to find any reference in Haynes. I'll look around some more, take a picture and post it. BTW, there is an oil cooler in the right front wheel well.

Thanks.

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Dan Shust
74 Carrera

Dan:

Now you have stumped me, for there should be NOTHING stock under the wooden footboard on the passenger side, except air (that's the reason people put the auxiliary amplifier there). Porsche AG did not put anything there. In fact, the only reason for the footboard at all, is to get the angle of this "floor" just right for the convenience of the passenger's foot.

Not having a picture of it, makes it dificult to "tell" what it is, but there really should be nothing there. This must have been
addded by the Previous Owner; but I question its efficacy, since that is such a small space (in volume), it has no fresh air ciculating in it, and thus it CAN'T be for REAL cooling purposes.

Have you tried to trace the connection to it? Where do leads, piping, whatever, go? This might be your only clue as to what it is supposed to "cool".

Can you give us any more information as to size, shape, routing, etc?.....Andras

I'll trace it tonite and let you know.

Dan

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Dan Shust
74 Carrera


[This message has been edited by dshust (edited 06-05-2000).]

Very heavy rains in Central Ohio tonite so I couldn't pull it out of the garage to crawl around. Here's a pic from the interior passenger footwell. There's the unidentified object...



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Dan Shust
74 Carrera

and for the record...here is a more flattering view:





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Dan Shust
74 Carrera

The car is gorgeous...butI have no clue what the hell that thing is! It sure looks like some kind of A/C radiator but I have never heard of one installed in that location. How would it even get any airflow unless there is some elaborate ducting?

Thanks! So, normally is there another access panel here or just a hole? Did someone cut that hole?

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Dan Shust
74 Carrera

It appears that the wall in front of the floor board has been 'opened up/cut' by the previous owner. Those fins are from the A/c box..which normally is incased in plastic. I'll go out on a limb here and say the last guy didnt like (or thought) the heat exchangers didnt cut it in the winter (they don't) and so decided to experiment. It's like using the a/c box as a heater core. Rather nifty, but what do you do in the summer? Open hood and open the lid-flap on the left side...is that the heat source?

Nice ride by the way!!

Dan:

I would say that the Previous Owner (PO) has been playing fast and loose with "your" car !!!!! And don't forget that even you are just a "care-taker" until the next owner. Too bad the PO didn't show any respect for his butchering job.

This is definitely an amatuer job, cobbled up for what reason I'm not sure. In the winter, my 1983 911 SC heats up within two minutes, no matter what the outside temperature, with enough heat to start warming the cabin. And with the flappers adjusted just right, NO HEAT gets in during the summer. So this PO must have been trying to accomplish something by placing a cooler in this position. It is definitely an AC expansion cooler, but what it is doing there is a real mystery. If you were to cut a hole there, you would be into the wheel well, I think.

Is that hole now into the wheeel well? If so, then do you get any water in your passenger compartment when it rains?

I would remove that "offending object", and patch up the hole, put some rubberized "rust proofing" on the wheel-well side, to get that hole closed. Be careful, though, to ascertain where the cooler is attached, since it does seem to be running hot liquid in it. You'll have to cap those lines too, for this installation and location is not doing anything for you.

Let us all know what you've decided... Andras

I was thinking about your 'radiator' wonder.
If I'm seeing the picture correctly, then it is the evaporator. You can open the front hood, pull back the carpet, and open that little hatch door. I 'was' thinking it was this evap...
If it is in the wheel well..it may well be an oil cooler..which is not getting good airflow to do its job. Coolers should be in the Valance, or front of right tire (under normal circumstances)
When you find out whats up..let us in on it!

Tlook:

We may be beating a dead horse here until Dan disconnects this "item" and sees what it is hook up to.

However, to be the oil cooler, the fins and oil line are going in the wrong direction. The oil cooler in front of the wheel has the lines going up and down in the vertical or long direction of the cooler; these are going in the horizontal or short direction, much like the evaporator, as you thought.

So let's wait until Dan gives us his findings. Don't we all just love a mystery?
But how can anyone justify the PO's callous disregard of a fine automobile by "hacking" that hole into the bulkhead? Arghhhhh..Andras

I'll start the dissection as soon as possible. Going up to the Stoddard Porsche swap meet this weekend so it might not be until next week.

Anybody need anything? (Oh,I shouldn't have asked that!)

Dan

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Dan Shust
74 Carrera

Dan:

I'll see you at the Stoddard Swap Meet. Look for me in a metallic brown 911 SC, with dark brown leather interior. I usually park in the used car parking lot, since I pretend to be looking at used cars. (Not nice, I guess but effective). Then we can look over your mystery. This has me intrigued, since the PO must have been a real klutz....Andras

Dan:

I'll see you at the Stoddard Swap Meet. Look for me in a metallic brown 911 SC, with dark brown leather interior. I usually park in the used car parking lot, since I pretend to be looking at used cars. (Not nice, I guess but effective). Then we can look over your mystery. This has me intrigued, since the PO must have been a real klutz....Andras

Years ago, when Nixon was still President, I was responsible for calibration and repair of test equipment, and various odds and ends of the electronic variety for a very large corporation. Somewhere up the corporate food chain, there was a survey some bean counter dreamed up ... about how the equipment we saw was being treated. On a form we had to fill in the type of equipment, property tag number, then check one of two boxes related to the condition and treatment, then sign and date the form and turn it in.

One of the categories was for 'Normal' treatment, and the other was 'Abuse' ...

At some point after having filled several hundred of those forms, I decided there needed to be a third category, since less than 5% of the equipment I saw had been treated what I would call 'normal,' and the rest had DEFINITELY been abused! What I suggested was that there be three catejories: Normal, NORMAL ABUSE, and Severe Abuse.

Normal abuse from previous owners I categorize as wiring under the dash, cut and spliced with wrong colors of wire, cracked turn or stop lamp lenses covered with red or amber tape, substitute fuses in wrong Values, relays or other devices spliced into the wiring harness, dangling by wiring, and no clue what the function is, splicewd wiring just twisted together and improperly covered by tape, substitute horn or fog lamp relays that cause blown fuses when said blown fuse is replaced!!!

Your 'mystery' rtadiator device DEFINITELY falls into the SEVERE ABUSE category! Good luck patching up the bodywork damage!!!

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Warren Hall
1973 911S Targa

Thanks Warren.

I once test drove a 75 that had the whole passenger footwell and smuggler's box converted to a subwoofer. We might need another category...



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Dan Shust
74 Carrera

You ain't seen abuse unless you've laid eyes on my first 911. I rescued that car from a total, complete, should-have-been-aborted idiot. This moron put epoxy on a leaking oil tank, wrapped the shifter nuckle with duct tape, disconnected the e-brake shoes, put sheet metal screws through the pan, removed the air cleaner (I'm sure he overfilled the oil and it puked back), and the wiring - my God the thing was a 3 ring circus going down the road - with no brakes due to blown pistons. I can't think about it any more............Man, did I learn a lot in a hurry.