Jevo

I reckon that the heater muffler / tube in the passenger side sill may have broken down in my 964 as the sill is getting really hot...

Has anyone replaced one of these sill tubes ever?? I've heard they are a pain... And really expensive!!!

Or has anyone run another tube inside to solve the problem??

I've been told the heater flap is working ok but should it always feed hot air through the sill???

Any help appreciated...

swftiii

Jevo,

I've had this same issue, but on both sides and it is because the PO or PO's shop ripped the ends off as they didn't know what they were doing.

History:
I researched and talked to a number of places before on this and went down the path of fishing a smaller diameter hose through the center and used aluminum tape and some rivets to fasten it to the elbow at the engine end. It has done well, but I wouldn't recommend using the same hose I used because is causes the hot air to smell a little bit. I found some non-smelling hoses on Amazon that I bought a few months ago and was planning to swap them out, but rarely use the heat in Florida so it is not at the top of the list.

Here is my post from the archives:
https://rennlist.com/forums/964-foru...t=hot+air+hose

Now:
The above solution definitely helped about 95%, but when I open the sunroof I get a little bit of heat from the sills and now that I'm in South Florida any heat is not helpful. I've checked on the pricing of the hoses and they have historically been over $600/side and that is the best price even a shop can get for them. Well, Sonnen has them at $400/side now so I've ordered a set.

Connecting at the engine end with the right parts is no big deal, but removing and replacing the hose requires access at the front. I have been told the area can't be accessed by other shops and experts, but my shop in FL has done this before and they said it wasn't too bad, so I did a little bit of self research and it looks like there is an access panel at the front where the old hose can be pulled out and the new one inserted. If you remove front fender liner you can see the access panel I'm talking about (at least I hope that is it). My shop quoted me a couple hours each side to do the job (they have done it before on a 993), but I am going to try it myself over the Christmas holiday. If I'm unable to do it then off to the shop the car will go.

Good luck and let me know what you do.

-Skip

Jevo

Hi Skip

That's a real great help... Thanks... I'd be really interested to know how you get on with doing it yourself for sure... I'd also be interested to see pics of the old one when you get them out!!

In UK these pipes are £350-£400 a side!!! So an alternative solution maybe required!

My problem stems from the pipe breaking down in the sill and hot air escaping into the sill which is heating up the roll cage to the point you burn yourself on the hoop behind the passenger!! I've currently removed the connecting pipe from the flapper on the engine to the sill pipe just to stop the heat but that's no long term solution!!!

If the sill pipe is uniform I may get one made up in silicone hose but we shall see!!

I look forward to hear how you get on!!

Jason

AOW162435

Similar thread on the 993 forum.



Andreas

swftiii

Great link Andreas - funny beginning when some didn't understand that there are hot air hoses in the sills.

Some of the pics helped me with my planning. Now I need to figure out how the 2 clips on each side work and once the new 'mufflers show up I can get to work. They are only available from Germany, so looking at 3 or so weeks.

-Skip

Dr Mitch

Started to notice more heat in driver footwell today - pretty sure my heater hose (which was replaced with dryer vent tubing) has a hole in it. Does anyone know the diameter of the heater hoses? 75mm??
I was going to order a more durable hose from aircraft spruce.
Tried searching, but couldn't find diameter for replacement hoses.
Thanks!

ADDENDUM:
Found it!
75mm x 350mm (in case anyone else is just as bad at searching!)

Matt Andrews

does all the heat for ventilation come from the headers? Or if you remove them is there another source as well? I don't need much heat here in SoCal, but enough for defrosters would be good if I elected to replace the headers with ones without heat boxes...

tbennett017

The heat comes from the heater boxes. Defrost will still work to a smaller degree if your A/C is functioning.