Re: Heater

Almost four years ago... I struggled with deciding should I purchase a sweet looking Silver '99 Boxster. She had low mileage, was a convertible, and drove like a race car. After sweating expensive repairs and wondering if it would be sensible to own a "two" seater... I immediately decided YES! By far one of the best decisions I have ever made. Could it be possible that a car could change your entire outlook on life? Maybe... perm-a-grin is a powerful force that most people would not understand!

For the most part my Box has been low cost... only maintenance and some small stuff: window regulator, water pump, a new top... but thanks to the folks here; did everything with pride myself.

Now I have a new problem and not sure where to start. All summer the A/C has been blowing cold! Now it is winter and the air is still blowing cold! Any suggesting how to best trouble shoot this? Seems the fan works fine. I do not smell any leaking antifreeze. Thanks David in Charleston.

Could have a blocked heater core.

dghii
2000 Boxster S 6speed 112k miles

Thanks Dghii.... I'm guessing a totally blocked Heater Core is least likely of the two. Found a Heater Valve for $19.99 online... so I'm planning to replace the valve and see if the corrects the problem. Can anyone tell me where and the best way to locate the Heater Valve. Thanks, David

actually flowing through the heater core and it confirms that teh heater valve is working.

If you check the heater hoses be sure you're careful about where you stick your hands, what you touch. You can let the engine idle and warm up and with the heater valve turned to full hot the whole time when you note the coolant temp gage needle has risen to nearly '180' shut off the engine before you start groping hoses and such so at least you won't get your hand in the belt.

Another possibility is that the air flap that controls how much air that is routed through the heater core is stuck (apparently closed) so no air is flowing through the heater core thus the chilled air is not being heated.

I'm not 100% sure since I've never owned a Porsche with a non-automatic climate control system but unless I'm sorely mistaken with the non-automatic climate control heater/AC setup both the heater valve and the air flaps have mechanical linkages that can come loose.

Sincerely,

MarcW.

You can access the heater core hoses under the battery cover. If water is flowing through the heater core, both hoses should be warm when the car is warmed up and the heater is on.

Hoses are in the center of this pic:

Also, try putting the defroster on. If it blows hot, you know you have heat at the core, and that the temp control head unit is OK. That being the case, it's probably the heater flap control (actuator). It's the little motor under the dash with the pink lever. I had the same problem last winter, and switched everything in the system with no luck. Out of desperation, I took the actuator apart, cleaned and lubed it, and it works like a charm (knock wood)!

Could not find a pink lever is it on the driver side or the passenger side?

Thank you everyone for the information.... and the pic! I now feel ready to fix this problem. Winter is almost here and having my heater back will take the frost of my perm-a-grin.

I'll post you on my results!

David, the above input is great but the more likely problem is the one I had and fixed on my '99 Boxster. The heater flap is a metal part that is basically a metal sheet with numerous holes in it to save weight. Porsche then glued foam to the outside of the plate to make it seal and make it airtight. With time the foam degrades and fall off. You may have seen featherweight plastic foam coming out the vents. This renders the flap unable to direct warm air from the heater core into the car. Porsche will gladly sell you a new unit for thousands. But there is a fix that has been done many times. You have to take the heater core out (easy job, no coolant loss) and remove the flap by cutting out one of the bearings (not so easy, but do-able). Then you can cover the flap with something permanent (I used duct tape with foam around the sealing edges) and re-install it. This completely fixed my problem. There used to be a link to the fix but I can't find it anymore. If you need a few pics of this fix the way I did it let me know and I'll e mail it to you.

Thanks... I have seen lots of foam from the vents... so why remove the core? to access the flap? Is the core under the battery or under the dash on the passenger side?

As suggest I checked the hoses and they were.... yeah... warm! The Heater Core is now removed and as Emmett for casted: The internal flap that blocks the external air seems in bad repair. It is about 2" wide and 9" long with big 1" holes. I did not measure this only a guesstimation. Out of about 8 holes only one has any foam left on it. The foam is very thin and seems to allow some air to move through the flap. Unfortunately now... way too much air is moving through!

Upon removing the heater core, I found the flap wide open. So that too may be a problem... I not sure if the normal position is open and it closes only when the heater is engaged or if my has failed open.

So I'm asking two questions. Please answer if you are willing.

1. Do you think it would be safe to cover the holes with Heat Tape? This flap when open rest very close to the radiator. But then again the box around the heater core is mostly some kind of fiber plastic that would most likely melt under extreme heat. How hot does that heater core get?

2. Is there some way to get the flap to close with the core removed? Could I maybe hook the core back up external of the box to watch the flap operate?

Thanks for all the advice and I love this board... Visit almost everyday... I never say much... very low key.



Edited 1 time(s). Last edit at 11/30/2011 11:03AM by SilverBox99. (view changes)

Quote
SilverBox99
As suggest I checked the hoses and they were.... yeah... warm! The Heater Core is now removed and as Emmett for casted: The internal flap that blocks the external air seems in bad repair. It is about 2" wide and 9" long with big 1" holes. I did not measure this only a guesstimation. Out of about 8 holes only one has any foam left on it. The foam is very thin and seems to allow some air to move through the flap. Unfortunately now... way too much air is moving through!

Upon removing the heater core, I found the flap wide open. So that too may be a problem... I not sure if the normal position is open and it closes only when the heater is engaged or if my has failed open.

So I'm asking two questions. Please answer if you are willing.

1. Do you think it would be safe to cover the holes with Heat Tape? This flap when open rest very close to the radiator. But then again the box around the heater core is mostly some kind of fiber plastic that would most likely melt under extreme heat. How hot does that heater core get?

2. Is there some way to get the flap to close with the core removed? Could I maybe hook the core back up external of the box to watch the flap operate?

Thanks for all the advice and I love this board... Visit almost everyday... I never say much... very low key.

For (1) while it may be safe to cover the holes with tape the tape blocks all air flow, I have to believe it was for a purpose Porsche used foam that allows some air to flow past/through it. So my suggestion would be to search out some proper foam and use that to (re)cover the flap.

Visit a shop that specializes in automotive heater and A/C systems and ask if it can supply you with suitable foam.

If this doesn't work out then visit a business that specializes in residential/commerical HVACs and see if it can suggest a source of the proper foam.

Or visit a well-stocked hardware store, even an A/C heater store than also does installation/repairs of these systems. Longer shot but visit an large auto parts store and see if any of the techs can offer you any ideas.

AFAIK, the heater core can't get any hotter than the coolant and the hottest I've seen the coolant get in my 02 Boxster is 226F.

For (2) I can't even make a guess. I'd have to see the mechanism up close to try to grasp how it works and what you might be able to do. My WAG is you should strive to fix the problem and avoid trying to reengineer (jury-rigging) some mechanical hack that will have the heater malfunctioning again or exhibiting other symptoms (rattles?) that will have you back in there again in short order.

Sincerely,

MarcW.

Yeah... heat again!!!

I tried to find some foam to tape over the holes but the foam had to be thin, strong, and heat resistent... not something I could find at Lowes or Autozone. So I went with Thermal Tape and left a part of the bottom hole open to allow just a little air flow. I do have heat now, but cant seem to get the heat on high. Turned the temp up to "HI" and still get mild heat. Turn on the Defrost; and it gets HOT real quick. So my next check will be the Actuator Boxster Bob talked about.

Also, could someone explain to me what the little button with a snowflake on it is suppose to do? It is right under the Auto button on the heater/air console. When I bought the car it didn't seem to have any effect on the system? But today I played with it some and even though I could not tell how it affect the heating and cooling... it seemed like the engine kicked up when I touched it... like it caused some kind of a load on the motor? So I have always thought the snowflake meant "Air Conditioning" but could not prove it. If it actuates something... is there suppose to be something that lights up to show it is working?

Thanks David

Actually since it is a mixing flap there should be no flow through it. It changes position via a motor (actuator) to control the cabin temp. The foam that deteriorated had a thin plastic layer that is air tight. So when you get another chance to work on it you need to fill all the holes completely and put thin foam around the edges to help seal at its extreme positions. The standard fix is to remove the flap by (a) removing the lower control arm attached to the actuator motor and (b) remove the top part of the top bearing with a dremel and cut off disk. With the top and bottom free, you can remove the flap and work on it. Then you can fashion a sheet metal Z bracket to hold the top bearing back on. I know it sounds drastic and crude but it beats megabucks to remove the entire heater assembly and work on it, which is what would happen if you took it to Porsche. If there is interest, I can pull all my photos together and create a procedure.

supposing there was some intentional air leakage thru porous foam.

Sincerely,

MarcW.

The heat is working pretty good now... I believe part of the problems was that darn button with the snowflake design. It appears to be a 2nd function button... you hold it in and then hit the up arrow to raise the cabin temp. Doesn't there have to be some air moving through the vane? Other wise you the cabin fan would be pulling/sucking on a dead end... no where to pull air from? Like putting a hole in in the bottom of a beer can... no flow until you pull the tab on top. Then you have a beer shotgun..(LOL)