Right Front Fender Hot to Touch After Drive

[Infinite5ths]

Hi folks! Loving the 2001 Boxster out here in Los Angeles :-)

I noticed an odd thing yesterday: After a relatively long, fast drive (45min-1hr on highways) back from Malibu to Glendale, the right front fender (metal panel over/around the wheel) was hot to the touch. Another highway drive today demonstrated the same results. The left fender is much cooler. The right wheel-well liner is very warm to the touch as well, though not as hot as the metal body/skin (opposite side cooler - just as it is with the metal body/skin panel).

At first, I thought perhaps it was a dragging brake pad, radiating heat out/up through the plastic liner & into the cavity below the sheet metal. I did recently replace front pads myself. But a few more test drives today seem to indicate that the right fender gets warmer than the left even under mild braking at slower speeds (i.e. in-town, gentle stop-and-go vs highway speeds).

I took the right front wheel off and checked the pads/caliper for any signs of issues. Everything seems fine; and I didn't notice a huge temperature difference (by touch) between the left and right caliper bodies after a subsequent test drive. (The one time I did have a dragging caliper on another car, that caliper was blazing hot, along with all of the lug nuts.) Steering has exhibited no pulling to the right (or left).

Headlights on/off don't seem to affect this either - so it doesn't appear to be an electrical or related issue. And the results are basically the same day/night - so it's not merely the sun heating my black paint.

Both radiator fans are operating, at least at idle and when stopped, with A/C engaged. I got out and put a hand under each exit vent and felt plenty of warm air being moved down and out of each radiator cavity.

The car is not overheating or showing any signs of odd temperature behavior. In fact, if I wasn't checking the smoothness of my my recent wax job I would never have noticed that the fender was hot. Once I did notice, a quick comparison showed that the left (driver's side in USA) was far cooler.

So I'm wondering if there is a known explanation for this. Mostly I'm concerned that whatever is generating the heat might cause issues for things up in the wheel well, especially up under the liner.

It's a base model, so no 3rd radiator in the center.

I'll do a little more testing with slow, in-town driving tomorrow. I suppose it's possible that this is still a brake issue; but there are no really obvious signs pointing to that.

Open to any suggestions for cause and/or troubleshooting...or, if the right fenders on 986's just run hotter, somebody please tell me! I'm a little mystified by all of this, given that I have no recollection of this left vs right temp difference until yesterday - despite lots of car washes & waxes.

[mikesz]

strange. I have a 99 Base and my right fan was not working and binding. I had to replace. That is the only thing I can think of. Make sure its working on both high and low speed the right fan I mean.

[itsnotanova]

Dirty radiator? Lots of debris can build up between the condenser and radiator

[Infinite5ths]

I’ve kept the front of the radiators pretty clean with a leaf blower. Never have taken the bumper off and moved the condensers: Would debris there cause heat to rise into the fender (rather than exit down and out the vent)?

Went ahead today and pulled the bumper + condensers to thoroughly clean condensers & radiators: Everything in there looked pretty good - less debris than I anticipated, though not immaculate. Hopefully that will restore enough air flow to cool the whole area and not collect heat in the fender.

[DWBOX2000]

I recently noticed when I was filling the tank it seemed warm, not hot but warm. Is that normal, should I expect a little heat? Thanks

[Jager]

Try driving without AC and see what happens. I suspect it's the the line that runs to the condensers... It is routed high on the inside of the passenger fender.

[Infinite5ths]

Good to know - thanks! My AC is almost always on, because I use the AUTO mode on the climate control...and it’s Southern California. 8-)

Will report back after a test drive

Originally Posted by Jager

Try driving without AC and see what happens. I suspect it's the the line that runs to the condensers... It is routed high on the inside of the passenger fender.

[Infinite5ths]

UPDATE: Runing at night (to eliminate heat from solar radiation as a variable) with AC off has the right fender back down to ‘merely warm to the touch’ rather than hot. I want to run it with AC on for an extended highway stretch again to confirm that the temp rises. But as of now, it appears Jager is spot-on about this problem.

And I now have double-checked my brakes and cleaned my radiators + condensers as an added bonus. Simple explanation + a bit of good preventative maintenance = better Porsche owner

[Infinite5ths]

Further driving seems to corroborate the results above. The right side front fender (passenger side in US) runs slightly warmer than the left with A/C disengaged, but MUCH warmer (hot) with A/C engaged - especially in hot (90degF+) temps.

Question answered