GaryC88

Hi guys. I have a 2008 Cayenne Turbo and I notice when driving hard (usually only in sport mode and WOT), that immediately after I get a strong burning smell inside the vehicle, that eventually wears off with softer driving.

It is not burning oil or coolant smell, more a hot metal brake pad smell. But I get it even If I'm not hard on the brakes (for example pushing it hard on a motorway). Has anyone experience this before?o

Petza914

What wheel and tire sizes are you running. If non standard, the transfer case might be working hard to keep the front and tear wheels in sync. How many miles on it and when was the TC and differential fluids changed. Turn PSM off and see if it does the same thing.

GaryC88

ive got the 21” 295/35/21 on. Factory wheels.

tbh I have no idea about TC or diff service, on my list of things to do. Id say its been a while.

But the smell is not a fluid burning smell, more a hot metal, burnt match kind of smell?

Petza914

Get an infrared thermometer and shoot the rotors to see if one of them is hotter than the others. Might be a stixking caliper. Both fronts should be about the same and both rears should be about the same, but the fronts and rears might be different from each other a good bit.

GaryC88

Thanks for the help! The odd thing is itll happen even if im not braking.

So for example, sunday morning, I had it in sport mode pushing it hard on the motorway up the slip lane to say around 120mph, lioft off the throttle then instantly through the vents comes a hot burning, almost fire, smell. But just cruise for a minute of so and smell completely goes.

Odd one, driving me nuts!

Petza914

When was the last time the driver's side intercooler was emptied of condensed oil? If it always happens on lift off, that's a high vacuum situation when the intake could pull oil from that intercooler. You sure there's no puff of smoke out the back that coincides with that. Also check your diverter valve operation under vacuum. They should "honk" if you start to build boost and let off quickly.

GaryC88

Yes the diverter valve makes the noise if I lift off quickly. I actually thought that meant they were ready for the bin!

Haven't got any smoke, had a friend behind me the other day when giving it some and he said it was all clear. Im familiar with burning oil and coolant smells. This isnt that. This literally smells like something has been on fire and put out. Like the exhaust has melted a carpet, or a burnt brake pad (even if not on the brakes at all).

When driving normally absolutely no smells. But give it some heavy right foot, only in sport mode, instantly you can smell it.

Petza914

Unfortunately, you'll probably figure out what it is at some point when something stops working.

Maybe take a look at the insulation on the wiring in the engine compartment to see I'd any has flaked off exposing bare wires. Maybe the wind coming in at high speed is pushing a bare wire against something conductive.

Morganmobile

How often and for how long do you drive WOT?

Guessing here but could you be smelling burnt cat? (Not the feline kind I mean)

cgpeders

It's your clutch pack inside transfer case trying to send torque to front end but it's slipping. Try replacing fluid and add ford's friction modifier to fluid. It may be too late for that and you will need a new transfer case clutch if you can find one. I have not been able too find one. Looking at a replacement transfer case now.

Jfrahm

Slipping belt maybe, have you smelled a slipping vacuum cleaner belt?

CTTS520

Thanks for posting this. I had the strange smell in my cabin after WOT for the first time the other day. I haven't repeated it because my Cayenne is parked until I have time to fix the "Brake Booster Faulty" error. The transfer case is do for service so I will take care of it ASAP. Will also inspect the serpentine belt.

thesteve

I read what was posted, but this sounds like valve cover gaskets.