2001 986 Heater

[MondialNeil]

Hi All

I am a member on the 911uk forum but no one seems to have an answer for my below problem, can anyone help ?

Well it has been 8 months since I last had my 2001 2.7 Boxster out to play.

The trouble is my heater is not putting out warm air when it is set manually anywhere between 18 to 29 on AC or none AC mode, you only get very hot air immediately if you set heater ti high.

Is this a known problem with a fix, I have read one problem that lay with the heater gate being full of holes after all the foam has broken down on it.

Any further help would be appreciated.

Regards

Neil.

[JFP in PA]

Originally Posted by MondialNeil

Hi All

I am a member on the 911uk forum but no one seems to have an answer for my below problem, can anyone help ?

Well it has been 8 months since I last had my 2001 2.7 Boxster out to play.

The trouble is my heater is not putting out warm air when it is set manually anywhere between 18 to 29 on AC or none AC mode, you only get very hot air immediately if you set heater ti high.

Is this a known problem with a fix, I have read one problem that lay with the heater being full of holes after all the foam has broken down on it.

Any further help would be appreciated.

Regards

Neil.

Your heater core should be hot at all times, you can verify that fact by checking where the water hoses enter the heater under the cowl behind the battery. Most likely, if your foam has broken down, one or more chunks of it are holding the air mix door in the wrong position when you set the car to heat. Pull down the heater box and clean it out, checking the doors for free motion and you should be back in business.

[stjoh]

It you need a new heater core let me know, I've got one I'll sell you for a good price.

[MondialNeil]

Heater core is hot, warm water going in and coming out, changed relay 18, read that this good be a problem. Anyway it was none of these so it must be a bit of foam somewhere, Oh boy !

Will have to try sorting this next.

[BFeller]

Originally Posted by MondialNeil

Heater core is hot, warm water going in and coming out, changed relay 18, read that this good be a problem. Anyway it was none of these so it must be a bit of foam somewhere, Oh boy !

Will have to try sorting this next.

Have you seen bits of green foam coming out of the dash vents?

[MondialNeil]

Hi BFeller

No, I have seen no foam, not one bit coming out of any vent.

Maybe it is something else.

[BFeller]

Originally Posted by MondialNeil

Hi BFeller

No, I have seen no foam, not one bit coming out of any vent.

Maybe it is something else.

I would have expected you to see some foam.

[Meir]

removing the heater core is not a very complicated task.
if you will remove it, you will gain access to one of the flaps inside the airbox, so you can clean it and the heater core from debris.

here is a write up i made couple of years ago.

check out step #1 in post #14

AC question

[MondialNeil]

Thanks a lot Meir, I will give this a go with your write up.

Cheers

Neil.

[Dlirium]

I have the exact same problem with my 2000 S that Neil describes. I don't see any foam either. I will try looking at the link as well.

I was initially thinking it might have to do with an air bubble in the cooling system...

Neil, please keep us posted with what you find!!

[MondialNeil]

Originally Posted by Dlirium

I have the exact same problem with my 2000 S that Neil describes. I don't see any foam either. I will try looking at the link as well.

I was initially thinking it might have to do with an air bubble in the cooling system...

Neil, please keep us posted with what you find!!

OK, will do.

Regards

Neil.

[MondialNeil]

Hi Guys

I have taken the heater core out and there is no foam anywhere in the box, the foam on the flap is all intact and in very good condition, no signs of breaking down.

The question I have now is about the flap.

When the heater is put on high the flap completely opens.

As soon as you set the temp to just below high the flap completely shuts, so at 29.5 c I get cold air.

Should the flap close in a graduated fashion when you go down in the temp settings, if it should then this is my problem as the door just completely shuts when not on the high setting.

[MondialNeil]

Hi Guys

This is the cause of my problem, info from Ahsai on Renntech:-


mondialneil, on 04 Jun 2014 - 7:20 PM, said:
Hi Ahsai

I will check the servo.

So the servo should move the flap bit by bit when you change the temperature setting ?

Cheers




Neil.
Exactly. The servo should move the flap proportional to the temp setting. It should be able to stay partially open so it can modulate the air temp by mixing the right amount of hot air with cold to get the exact temp setting you chose.

In other words, as you change the temp setting gradually, the flap should move bit by bit. That's why there's a potentiometer inside the servo that provides a varying output depending on the degree of opening of the flap. I hope that makes sense.

[Dlirium]

So, quick swap of the servo and you are all good? how hard is that to get to??

[MondialNeil]

Hi Dlirium

When I get the replacement I have ordered I will tell you if it corrects the problem.

It would seem though as mine only opens on HI for hot air and then shuts when moved from Hi and the fact that the servo graduates the opening for the temp scale where mine is shut tight this will correct the problem.

On my UK car the servo is in the passenger side footwell on the underside of the heater box, not hard to do from what I have seen.

Cheers

Neil

[MondialNeil]

Yes Yes Yes it is sorted.

It was the cabin ambient temperature sensor, the one that sits behind the passenger side air vent.

One of these came up on Ebay for £10 secondhand so I bought it, just to try, as it was not too expensive.

Also I had read somewhere this could be a culprit and it was.

Happy chap now lol

[Dlirium]

Wow, fantastic news! I may have to try that too if I can get my hands on one over here state side! Thanks for the update!