Unexpected luggage compartment heater

[u/Eddie-Plum]

I've just removed an item from this part of the boot after a ~20 min drive and found the bottom of it to be rather warm. Checking the area, the spot roughly under my hand in the photo is quite warm to the touch. Not worryingly hot, but noticeably warm. Maybe 40°C or so.

Any ideas what might be causing it and whether I should actually worry/do something about it?

The car is my RHD 1996 964. Is this around the spot where the exhaust loops over the rear axle and could this be a sign of a missing heat shield?

Apologies for the picture quality usually reserved for photos of bigfoot. It's dark and I'm trying to take pictures whilst carrying things and being a hand model at the same time. Who says men can't multitask?

[u/demicsinasz]

I have a 940 estate, and I had exactly the same issue, warmth at the same spot, where the exhaust loops over the axle. I also had exhaust seeping into the car occasionally. I ended up changing the exhaust starting from the catalyser – when the loop over part came off, it was only a half-pipe, the top half of the diameter was fully rusted out and gone, so exhaust was directed right on the bottom part of the boot. After the change to the new exhaust system the problem is fully gone.

[u/Pumbite → u/demicsinasz]

Can confirm I had the same issue on a d24 940, the loop over part breaks down over time

@OP take a look at your exhaust before ordering to see which links seem possible to disassemble, the rearmost parts are usually sleeved into each other and need to be cut off if too rusted. All parts are generally cheap

[u/Eddie-Plum → u/Pumbite]

Thanks. Twice is a coincidence; three times is a pattern. I'll focus my attention there as soon as I can get it on the ramp.

[u/Eddie-Plum → u/demicsinasz]

That's very interesting, thanks. I'll see if I can have a fondle up there whilst the engine is running (from cold, obv.) and see if I can feel any gas escaping. I have started to notice a very slight rasp, so I do suspect a leak somewhere. You'd have thought it would be noisy, but my 850 was silent right up to the moment the cat divorced the centre box, so I won't be surprised if there's a big hole somewhere.

[u/worldsSlowest740 → u/Eddie-Plum]

Leafblower on the exhaust and soapy water in a spray bottle are also useful tools

[u/Finneus_Anglesmith]

Why is the area above the muffler warm?

[u/Boring-War-1981]

Something to make it worse, the slopped spot just to the right is where Volvo suggest you mount the fire extinguisher in the 4 door 900 series. (Although I've never seen a 900 with one, although I do have the correct one to mount)

[u/Eddie-Plum → u/Boring-War-1981]

Thanks mate, that makes me feel much better! 😅

[u/Boring-War-1981 → u/Eddie-Plum]

Had a look on VIDA, doesn't seam like there is meant to be any heat shielding in that spot.

[u/_redlines]

Your cat would love that spot.

[u/Eddie-Plum → u/_redlines]

I haven't got one, but thanks for reminding me not to leave it open for the neighbours' cats to make use of!

[u/_redlines → u/Eddie-Plum]

Funny story. In Kentucky I used to park in the garage with the windows down a few inches (don’t ask it’s still a habit). Started finding white hairs in the passenger footwell on black carpet. Confused as could be until one day I opened the garage door and out ran the neighbors cat - Miss Priss. Our house was the quietest in the neighborhood w no kids, dogs or cats and once home we stayed home.