Kettengesicht

Faint yellow discoloration behind side-vent

Hello everybody,

I'm a new Boxster owner, and it's my first Porsche. A few months ago I bought a 2004 Boxster with 49k miles on the clock, in what appeared a very good condition. Being a CA car the body seemed in excellent shape, and I have experienced zero issues in the first two months. After a while I noticed a slightly rubbery smell, and going through a number of forums it seemed that this was either normal or possibly an issue with the serpentine belt. So I went ahead and replaced the belt. The smell seemed to be less, but it was hard to tell. Otherwise the vehicle was problem-free, aside from minor cosmetic issues.

Fast forward to today, I washed the vehicle and noticed a strange discoloration on the passenger side slightly behind the side-vent. (see attachment above) My first thought was that I'm looking at a repaint gone wrong, or that maybe some filler is holding the heat that would cause the discoloration. The top-coat seems very much intact, smooth and shiny, so that I'm rather sure that the discoloration is not caused by something externally. I have searched the forum, but I don't believe I have come across something similar. (I do apologize if I overlooked something.)

Did anybody here have a similar experience?

Anker

That vent is the exhaust for the engine cooling fan. You have something leaking off the engine that causes the discoloration. My guess is that it is oil, but it could also be coolant or even rubber burning off the accessory belt.

This is something you need to get fixed. It must be pretty bad for it to cause the deposits on the paint. You probably have the cars behind you swearing at you.

Kettengesicht

Thank you for your response!

What puzzles me is that the car consumes only minimal amounts of oil and no coolant. The deposits in the picture are also under the clear coat of the paint. (I increased the contrast to show the spots, I cannot find any discoloration on the vent itself.) There was nothing to wipe off, and the spots appeared suddenly within about a week. There is nothing on the garage floor, there are no oil spots on the driveway when I wash the car. I have however installed a new serpentine belt recently.

But in either case, I will likely have to have it checked out.

P.S.: Out of curiosity, I thought the passenger side vent was an intake and the exhaust was on the driver side. Am I wrong?

paulofto

Intake is on the left leading to the air filter, MAF, throttle body, intake manifold, etc. Hot engine compartment air is forced out by a cooling fan on the right.

Kettengesicht

Thank you, I was wrong about it then.Thanks for letting me know.

Kettengesicht

Better picture of the discoloration

I decided to take the Boxster for a spin an check for anything leaking from the passenger-side vent, so I drove it for about 20 minutes across Ohio's country roads, and pulled back into my driveway. The area was bone dry, and it smelled like hot engine, not like oil or coolant. What I did notice was that the discolored areas seemed slightly warmer than the rest of the panel, especially that square area close to the vent.

In any case, this didn't get me any closer to the reasons behind this phenomenon, so I will have a shop check this out.

Macster

Hot engine compartment air is *not* forced out the right side vent. The vent is positioned at a "high pressure" area so when the car is moving air is being forced into the vent.

When the engine compartment gets hot enough to trigger the fan the fan pulls air in through the vent and blows it down/across the engine. The hot air exits the engine compartment from underneath the car.

Unless somehow the fan has been messed with and the motor runs in the reverse direction (if this is even possible) no hot air of any real amount sould exit the vent.

Sure if one parks a car with a hot engine some hot air might leave through the vent but not in any amount to affect the paint or paint finish.

Macster

If you (or the shop) don't find another explanation I'd not rule out the possibility car has had some paint work.

But let the shop check the car out to make sure the engine compartment fan works as it is supposed to, pulls air in through the vent and doesn't blow air out through the vent.

Also be sure the under body panels are all intact, are properly secured and this includes the rubber "scoops" that are at the leading edge of the underbody metal stiffener panel that these are intact. These are supposed to be for brake cooling but I would want everything right.

Airflow under the car is as important as air flow over/around the car.

Kettengesicht

Thanks for responding. The square spot behind the vent made me think the same thing. (Aside from a felt piece missing in the trunk on that side.)

Yeah, I will take some time off these week and get an appointment. I wouldn't know exactly what else to look for at this point.

P.S.: I hope the Bay Area is alive and well. I miss that place at times.

paulofto

You are correct Macster. I meant to say drawn in the vent and forced out the bottom. My bad.

From the service manual I believe.
https://www.renntech.org/forums/uplo...1402405977.png

Kettengesicht

So, I took it to an independent mechanic, and was willing to have it checked out thoroughly, but he wanted to take a look first. He asked me to open the rear trunk, felt the seams and knocked slightly on the spots. He was certain the panel was worked on, and that filler was showing. He recommended a body shop to fix the paint job. He did not want anything for his service, other than asking me for my future business. (Which he will have, as I couldn't even set up an appointment with my local Porsche dealership.)

I'm happy it's nothing too serious.