"NO HEAT" inside of Boxster

[dedes]

Thanks Loren

I knew you would show up sooner or later :)

I will do that.

[1schoir]

Dedes:

In case you are having trouble locating the heater core from the outside of the car (forward of the base of the windshield, just behind the battery) it's because it's hidden under a foam liner cover, behind the firewall with just the inlet and outlet tubes (and their corresponding hoses) sticking out.

Here is a photo, showing the foam liner cover removed and the two hoses temporarily connected :

The coils are beneath the brown plastic top cap of the core.

With the car properly warmed up, and the heat settings on high, you should be able to feel that both hoses are hot, as coolant should be flowing through both of them. The inlet (see the arrows on the hoses) should be slightly warmer than the outlet, but I don't know if it's enough to feel a difference.

Regards, Maurice.

P.S. Thanks for the Pedro update.

Edited January 13, 2008 by 1schoir

[dedes]

Now that I have printed up all this great information, had some coffee, I am headed up to my car in the garage.

Stay tuned everyone! I shall return.

[dedes]

Hello and hope this makes sense to all of you.

I checked the following:

Coolant filled to the max/normal

Did air purge - not sure if I did it long enough to get the air bubbles out of the coolant

Checked oil - oil dipstick is normal

No odor of anti freeze

Per juniinc - Tried the hidden 986 AC Diagnostics - holding down recirculating button & air up buttons for 5 seconds, etc. - did not work, no codes displayed. Do you hold both recirculating button & air up buttons for 5 seconds simultaneously? I did them simultaneously.

I think I have a faulty flap or better said a arm to the flap. (I can't tell if arm is broken or not) But I hear a slight quiet clicking/flapping noise when I start the car and when heater is activated. Sounds like the valves or flap trying to open up. I looked into that small area behind the controls/dashboard and saw a blue plastic arm and a pink plastic arm further in the back. The pink colored plastic arm (must be the valve you are mentioning) moves slowly or not at all sometimes ( moves slowly like it is thinking what to do next) when I turn up the heater fan.

I turned up the heater blower (highest level) I get a lot of air like it would be normally. And then when I lower the speed I get less air blowing. At lowest level at 72 or less degrees air feels just warm(coolish) not warm enough I think. If I raise it to 76 or 78 degrees it gets much warmer/hotter in the cabin. When I turn off the heater completely I hear a very soft sounding noise, like a fog horn blowing. Could that be the fan? (heater is off) The noise is coming from the passenger side area near the door. I also can hear it slightly outside of the car if I put my ear up to the corner of the windshield on passenger side. Or is this something entirely different, because my engine was on and parked.

Possible problems:

Under the hood area - checked the two hoses to the heater core near the battery area - they are warm/hot to the touch

As Loren said: It should feel warm. If it does then the problem is the the heater controls under the dash or a bad air flow temp sensor.

As Pedro said: A sticking valve that won't allow the hot coolant through the heater core.

As Glyn mentioned: might be something such as Inside temp-sensor mounted in the aspirator assembly at the side of the dash/Temperature mix Flap command/Temperature mix Flap position

Did I forget anything else?

Would autozone do a durametric diagnostic? If not I can take it to my mechanic to check it with the durametric.

F.Y.I., My car is not my daily driver, just for weekends, etc. So I am not overly concerned about "no heat" at the moment. I do want it fixed though or confirmed its ok.

Again thanks to all of you,

:renntech:

Dede

Edited January 14, 2008 by dedes

[Glyn]

Wasnt going to reply but i just couldnt resist

Juniinc, No offence but i did think the head gasket was going to the very serious end of the scale, and yes i know they can and do go, but if the heater was working perfectly one day when the car was parked up then nothing the next then this will be the first head gasket to blow when cold.

I do have a tiny bit of experience of engines as my trade was a motor vehicle mechanic many years ago.

I agree there are many reasons for no heat but start with the no cost checking options, then the low cost options, move towards the more intensive options if all else fails.

The Porsche is a wonderfull motor, but this marque also has very high costs for spares and mainly drivers are just that drivers - not automotive experts, Nothing puts more fear into a driver than the thought of a repair bill on the Porsche, we all know drivers that are running their cars on a tight budget and thoughts of head gaskets must be a terrifying thought when asking "How much"

I just had to come back to the head gasket though - It is more likely if the gasket is blown to boil up the car as heat from the cylinders escapes into the water jackets - of course after boiling up and the water level sufficiently reduced then the heater would go cold - but i just think the owner may notice this and have reported this in the initial write up --which he didnt.

Honestly i have never seen a car run cold on the heater when a head gasket has blown - always the boil up.

I guess the proof of the pudding is in the eating - we await the final diagnosis and rectification points

[gstoli]

When I turn off the heater completely I hear a very soft sounding noise, like a fog horn blowing. Could that be the fan? (heater is off) The noise is coming from the passenger side area near the door. I also can hear it slightly outside of the car if I put my ear up to the corner of the windshield on passenger side. Or is this something entirely different, because my engine was on and parked.

It happens that just today I removed the passenger side vent and checked what this noise is. A constant noise exactly as you describe it "like a fog horn blowing". It's the "interior sensor side vent" (number 17 in the attached picture):

What is that? It costs about a 100$!!! I took it out and cleaned it, did a hack to stabilize it but the noise is still there (you can here it when the car is on but the engine not).

BTW I have always hot air coming in, which is perfect fro winter, but I will have eventually to fix it, so, please, keep the dialog open...

George

Edited February 10, 2008 by gstoli

[RFM]

This sensor sucks the interior air around his build in temperature element with a small fan to correct the out flow air temp. of the climate system. This suction is needed to have a swirl around the temp. element, which is more correct than stagnant air. It is the fan that you can hear, replacing is the only solution on long term.

[dedes]

This sensor sucks the interior air around his build in temperature element with a small fan to correct the out flow air temp. of the climate system. This suction is needed to have a swirl around the temp. element, which is more correct than stagnant air. It is the fan that you can hear, replacing is the only solution on long term.

Sorry, I don't have a resolution to my "Heater Problem" just yet. I haven't taken my car to my mechanic. (he is not close by to my house) My car isn't a daily driver and so it is sitting in the garage for now. I did take it for a spin this weekend and the heater was working great. But I kept it off after I noticed it worked. Temp. gauges, oil & coolant levels all look good. I think it could be a sensor, sticky valve or flap or faulty fan, not sure until someone checks it out for me. Once I know I will definitely post the results here.

Let me know gstoli what you find out about the noise, "low fog horn blowing sound" or other symptoms and results if any. As you said, keep the dialog open...

thanks

dede

Edited February 11, 2008 by dedes

[gstoli]

Let me know gstoli what you find out about the noise, "low fog horn blowing sound" or other symptoms and results if any. As you said, keep the dialog open...

Really, there is not much you can do. Get the sensor out, clean it, lubricate it... done. It is much much better now. I can still here it in my garage (absolutely quite environment), when the engine is off (but the power on), but again maybe I am overreacting, maybe some noise is normal to be there...

Anyway, I would prefer to spend 100$ on a clear brake light and not this :)

FYI I have read that turning the sensor upside down may give you another year or so of "silence". It did not work for me, but you may want to try it.

I think it could be a sensor, sticky valve or flap or faulty fan, not sure until someone checks it out for me. Once I know I will definitely post the results here.

I know it is a faulty flap in my case, and I can hear the same clicking sound when I turn on the A/C. Maybe, next weekend I'll open it and check it out. I'll post an update when I do that.

George

[rsfeller]

OK, I think you are on the right track but confused, or just using the wrong works.

The arm located under the dash that I reference in my write up controls the mix (not the fan speed as you state). If you take the arm off (I believe it pink too) you can manually move the flap through it's travel from point A to B which is from warm air to cold air and back. You can manually do this to simulate full heat or not. No, I don't know which direction is warm or cold but you only have two options. If you can manually simulate the movement and get a solid feel that the door at both wide open positions (good seal) then you have a problem with either the servo, broke arm or something wrong with the ACC computer not giving the correct command (such as a failed internal cabin sensor)

If you do crank the blend door from one side to another and back and cannot determine ANY heat then you have the same issue as me, big holes in the door due to the foam disintegrating. You foam is all gone from your blend door and there is no way you are getting full heat from system even knowing your core is good, door is moving, servo is working and ACC computer is operating as expected. Re-read my write-up.

If you door doesn't move then you have yet another bigger issue and will need to do surgery like me. Scary but easy.

I believe you still have not determined the root of the issue. Forget about the the interior cabin temp sensor regardless of how noisy it may be. The failure of the motor in there has little bearing on the movement of the blend door under most conditions as the sensor is most likely still taking a good reading. YOU NEED TO FIGURE OUT if you door is moving first. Failure of both the sensor fan and sensor at the same time is highly unlikely IMHO.

FYI the noise of a bad cabin sensor fan can be temporarily fixed by a good shot of silicon lubricant into the motor. done it cars for years often getting 5+ years out a motor that was honking or squeaking prior. Keep in mind you should try to miss or clean the sensor gently, I'm sure it being covered in lubricant isn't the best way to get a good sensor reading.

Shawn

The link to my page again:

http://www.carboncow.com/pages/porsche/heater_door.htm

...and I knew the Audi diagnostic doesn't work!

Edited February 12, 2008 by rsfeller

[dedes]

Shawn

I am having trouble opening up your write up below. Message is "taking to long to respond". Could be my computer for some reason. I will try later. Thank you for all your information. I am hoping to look at the car again today with my husband (another set of eyes). Hoping to have a more general idea of what is going on. I do like to try to figure out things myself before taking it to someone. Like I said my car is a garage queen. I do need to take care of this problem before the good weather driving for California sets in. I will more than likely take the car to the mechanic. I will definitely post the end result for everyone.

Dede

The link to my page again:

http://www.carboncow.com/pages/porsche/heater_door.htm

[dedes]

Shawn

I am having trouble opening up your write up below. Message is "taking to long to respond". Could be my computer for some reason. I will try later. Thank you for all your information.

Shawn disregard the message above about not opening up your write up. I finally got it opened.

dede

[rsfeller]

I know you stated you got the website to work. It is hosted on a home server so a bit slow at times. Just in case others find this link in the future they can download a PDF of the page along with hi res images here:

http://carboncow.com/images/temp_air_mix_flap_writeup.zip

I created for another viewer who had trouble with the website.

Let me know if I can answer any more questions.

Shawn

[dedes]

Ok, I am back with the results on my car. Sorry it took so long.

After my heater wasn't working I noticed my A/C wasn't working. So I decided to take my Boxster to my Porsche Mechanic. Well the A/C needed to be recharged and the heater is also working now. Both blowing hot and cold air. My mechanic checked it out and everything is fine now. I told him what was going on in the past. Apparently I needed A/C service and few other things below that may have triggered the problems I was having.

Also, did some minor service work.

Oil change & Filter

Checked and filled all fluids

Brakes checked

Inspected Tires

etc....

I also had to do a "Test Only" smog on my car.

My mechanic did the smog check and it passed the "test only". After the smog test, on the next day he took my car for a test drive and a CEL came on - found faults in ECU for Secondary Air Injection, no flow detected. Found faulty combi valve. Replaced combi valve, Vac Reservoir and switchover valve.

Found where the vacuum leak was occurring and found a faulty engine oil filter tube bellows leak, replaced the bellows. (saw the bellows part and it had bad cracks on it) Replaced the bellows which required removal of the coolant expansion tank, replaced tank at the same time as the bellows was being replaced.

F.Y.I. - I had purchased a Porsche Coolant tank awhile back, thinking it would be a good idea to replace on my car soon.

Also, recommended the water pump, water pump gasket, thermostat and worn belts be replaced, included flushing the coolant system. Replaced all parts there.

After inspection determined that the vehicle required an updated vapor separator based on mileage; recommended that the J-tube be replaced; (J-tube was a old part) this service included a thorough cleaning of the engine which was contaminated with oil extensively; this would prevent further deterioration of the rubber and plastic components in and round the engine compartment.

All in all my Boxster needed some work. And now ready for some summer driving! :)

Sorry for taking so long to respond back to all of you. I learned a lot from all of you and I appreciate your help.

Dede

[rsfeller]

But what was the cause of lack of heat, nothing in your details explains that!

[dedes]

But what was the cause of lack of heat, nothing in your details explains that!

My mechanic checked it out and it was fine or he fixed it. Not sure what he did, I will ask for more details. Plus I will keep my eye out on the heater for the next couple of weeks. Sorry if I sound so vague about this heater thing.

[rsfeller]

I'm just curious and concerned if "the heat" is actually fixed then since it was an important failure point in the post. Since it's warm out I"m curious if you are getting heat, warm or just not sure.

[juniinc]

kinda a lot of work&parts? what's the mileage on her?

[dedes]

kinda a lot of work&parts? what's the mileage on her?

77,419 miles

[mills914s]

I am having the same problem, Heat and air work fine, door that mixes does not move at all. I disconnected the flap arm it opened and closed fine cold then hot air. So the problem must be in the temp sensor or the electric servo that moves the arm ? An I right ? is there relay's involved in this operation? Where should I check first ?

[mills914s]

I fixed my heat problem by putting in a new/used climate control computer. I found one for a hundred bucks and now everything works great.

[logray]

Interesting thread. Since it's going all over the place I suppose I'll add my two cents too and hopefully it will help someone. ;)

Recently my car started blowing warm air through the vents even on Lo, and as the car warmed up the air became warmer, but never hot (outside air temp 68F). With the A/C on the air would cool down somewhat and the air con system appeared to be engaging fine, but was not the artic chill I am normally accustomed to.

Out of the possiiblities discovered during the search, I suspected either a flap, compartment temp sensor, or A/C charge issue to look at first (car is 1999 MY).

I started with the compartment temp sensor. After removing the psngr side vent, I found that the compartment sensor and micro fan was completely caked in dust. I cleaned it with compressed air and electric parts cleaner, then shot a tiny amount of silicone spray into the fan, then reassembled. Much quieter now!

Next I moved to the hot/cold flap under the middle of the dash. I checked the actuation of the flap from Lo to Hi and saw that it was moving just fine. I did notice the piece that attaches to the flap was moving up and down as the arm moved, instead of just swiveling. I removed the actuating arm from the swivel piece and noticed that the flap fully open and fully close positions were different from the max positions of the motor. I pushed the swivel piece into the flap more securely (It seemed to have dropped down somewhat) and also rotated it left and right several more times to feel the open/close position. I'm not sure what happened at this point, perhaps some of the flap's foam broke off, but for some reason the max and min positions for the flap suddenly went to a state that agreed with the actuating motor (about a 1/2" difference before after). I reattached the arm to the motor and tested. The problem was fixed! No more warm air on Lo, the heater was working fine, as was the A/C.

One thing to note the hot/cold flap motor seemed to move about 3 or 4 very very small "ticks" more after fully hot or fully cold was selected. It would also move a tick or two towards hot on "Lo" and A/C on. Not sure if that is normal, but the system seems to be working fine... for now!

BTW I have all of the diagnostic tools to read the flap position and compartment temp sensor, but ended up not needing them.

Also concerning some interesting conversation earlier in this thread... for the record a busted head gasket is NOT something one would consider here as a culprit. The head gaskets on the M96 engine are made of multi layer steel and are pretty much one of the strongest things on the car, and HG failures are not only very uncommon but almost unheard of for these cars...

[cpy]

Hi, i just wonder at passenger side, the fan behind the sensor, is it allways on? i noticed even when i turned the key of, or leave it next day, the fan is still rotating?

[rsfeller]

Hi, i just wonder at passenger side, the fan behind the sensor, is it allways on? i noticed even when i turned the key of, or leave it next day, the fan is still rotating?

CPY, if you want proper answers you have to create a new post. What you did is called highjacking and although slightly annoying to those who know how forums work...more importantly you are writing to a very small audience of people that have already posted on this older thread. Try a new thread with your question and you may get better comments. Good luck.

[manud]

Interesting thread. Since it's going all over the place I suppose I'll add my two cents too and hopefully it will help someone. ;) Recently my car started blowing warm air through the vents even on Lo, and as the car warmed up the air became warmer, but never hot (outside air temp 68F). With the A/C on the air would cool down somewhat and the air con system appeared to be engaging fine, but was not the artic chill I am normally accustomed to. Out of the possiiblities discovered during the search, I suspected either a flap, compartment temp sensor, or A/C charge issue to look at first (car is 1999 MY). I started with the compartment temp sensor. After removing the psngr side vent, I found that the compartment sensor and micro fan was completely caked in dust. I cleaned it with compressed air and electric parts cleaner, then shot a tiny amount of silicone spray into the fan, then reassembled. Much quieter now! Next I moved to the hot/cold flap under the middle of the dash. I checked the actuation of the flap from Lo to Hi and saw that it was moving just fine. I did notice the piece that attaches to the flap was moving up and down as the arm moved, instead of just swiveling. I removed the actuating arm from the swivel piece and noticed that the flap fully open and fully close positions were different from the max positions of the motor. I pushed the swivel piece into the flap more securely (It seemed to have dropped down somewhat) and also rotated it left and right several more times to feel the open/close position. I'm not sure what happened at this point, perhaps some of the flap's foam broke off, but for some reason the max and min positions for the flap suddenly went to a state that agreed with the actuating motor (about a 1/2" difference before after). I reattached the arm to the motor and tested. The problem was fixed! No more warm air on Lo, the heater was working fine, as was the A/C. One thing to note the hot/cold flap motor seemed to move about 3 or 4 very very small "ticks" more after fully hot or fully cold was selected. It would also move a tick or two towards hot on "Lo" and A/C on. Not sure if that is normal, but the system seems to be working fine... for now! BTW I have all of the diagnostic tools to read the flap position and compartment temp sensor, but ended up not needing them. Also concerning some interesting conversation earlier in this thread... for the record a busted head gasket is NOT something one would consider here as a culprit. The head gaskets on the M96 engine are made of multi layer steel and are pretty much one of the strongest things on the car, and HG failures are not only very uncommon but almost unheard of for these cars...

 

Very interesting thread (yeah 4 years old but still very useful)!

 

Same prob than you, logray. I started by checking the sensor just like you. Cleaned it and tried its operation with a hair dryer (!) I blew hot air on it and saw the aircon control module adapting its blowing power accordingly (temp was set to match 23C (73.4F) in the cabin). However, this did not solve the issue.

 

The symptoms: when at low fan speed, the system blows cold air all the time irrespective of the temp set on the control unit. When increasing the blowing power, the system reaches a point where I clearly ear a noise of a valve closing (or opening, you cannot see it) all the way. Pretty much like a small door being slammed, only muffled. At that point, the system blows hot air all the time irrespective of the temp set on the control unit, assuming engine is at operating temp.

 

This is when a stumbled across your post. I checked under the dash, passenger side (right side for me) and saw control swivel pieces in purple and yellow colors underneath a strong foam cover right below the passenger airbag compartment. My attention was drawn by the plastic rod connecting the swivel piece. The rod is connected to a cylinder-shaped piece, which has a slit on the top part. Obviously, it means that the slit is normally connected to a male piece somewhere. In fact just above the cylinder-shaped piece, I saw a female cylinder in which I could feel the male piece (still following?). That male piece is connected to the valve inside the air ducts. Apparently this valve is responsible for the cold-warm air mixture. After a couple of attempts, I managed to re-insert the cylinder in to the other one and assembled the slit with the male piece. Then I could see the control swivel piece moving the plastic rod and in turn rotating the cylinder connected to the valve. And voilà! Heating system fixed!!! 

 

Thanks you so much for this, logray. It saved my day!

 

Videos of this fix will soon be available on my youtube channel (https://www.youtube.com/channel/UC56Y8BE3XlFeLjALtJJ9PBQ)

Edited April 13, 2016 by manud