bowmanjp

Hi folks! I just joined the forum but have been reading for the last couple weeks leading up to our purchase. Just traded my Silverado in for an '06 CTT for the wife (her dream car). This thing is clean, 96k miles and still smells new on the inside. I used to work on old BMW, Jag, MB and occasionally Porsche in high school back in 2002 so I have a small idea about these cars but it was never anything this nice or new so there's still plenty foreign to me.
It's a one owner car but I didnt get any records from the dealer. When I checked the oil it was low and seemed like it hadn't been changed in a while. Which is really odd considering the condition of the rest of the car. So since I don't know what has and hasn't been done I'm coming up with a maintenance list now to get it caught up to date for the 100,000 mile service. This is what I've got, let me know if I should add or change anything.

- oil/filter changed
- air filter changed
- cabin air filter changed
- headlight bulbs all changed
- spark plugs and coils soon
- tranny fluid and filter soon
- brake fluid soon
- Bluetooth CDC thing on order
- rear lift gate and window supports soon

this is what I'm unsure about
- considering replacing the battery now cause I'm sure it's old, I hear it's hard to get to and can cause a lot of weirdness when it gets old
- not sure if I should plan a timing chain change now or not?
- do I need to change differential fluid or anything?

anything else I'm missing?

Thanks guys!
-Jason

nodoors

Baselining a car with ~100k miles is always a good idea

1. No timing chain service, battery is easy if you have two normal thumbs.
2. Both diffs and transfer case fluid
3. Check HVAC drain tube
4. Check sunroof drains
5. Diverter valves
6. Check brake pads
7. Check to make sure the coolant tubes have been done. Bonus points for coolant tees behind engine.
8. Get the car really hot and smell for burning coolant.
9. Check the rubber between the driveshaft support and bearing to make sure it is fresh and not about to come apart!

nodoors

10. Check the Air to oil separator diaphragm
11. When you change the oil empty the puddle of oil that forms in the driver's side intercooler pipe

These cars do use oil and the small turbos do a nice job of cooking it. How much can vary quite a bit between individual cars.

bowmanjp

thanks!

Ive been looking for my borescope to check the coolant tubes, I will do that as soon as I can find it. I can smell a little burning coolant when it gets hot so that's been my #1 concern. No codes and engine runs good so I doubt it's a head gasket, but I can't find any leaks either yet so I'm hoping it's nothing major. That's good about the timing chain. I'll have to look up all the valves and drains. Thanks again!

nodoors

Check the expansion tank, tees behind the engine, coolant tubes, and water pump. In that order if there is nothing else obvious. Changing the water pump, coolant tubes, and tees are all going to be a bitch. It makes sense to do it sooner than later before they kill your starter and ruin the transmission seal! Seriously.

bowmanjp

will do, thanks!

BlackTurboS

I believe you should do the hydraulic reservoirs and fluid change. For the low cost, it ensures your PDCC, if equipped, and your power steering stay clean and ready.

Travis

Congratulations on the CTT! Our CS has been great so wishing you all the best with yours.

Only two things I thought of in addition to the list above are:

Check the lower control arm bushings.
Parking brake strut. These are easy to replace and ensures the pedal comes back up to the released position.

hope the baseline line work goes smoothly.

docwyte

06 doesn't have pdcc so no worries there. Diverted valves don't seem to go bad on these, don't worry about that.

Definitely check all the coolant pipes, tees and overflow tank. Change them if they're plastic.

Lower front control arms are probably shot, do a fluid change on everything.

nodoors

That's just plain, old bad advice.

They are probably okay, as are the other things we are telling him to check out. After 100k miles and 10+ years it is unwise to think that a spring and diaphragm are definitely still working the same as they were - especially since the driver's side is constantly exposed to hot oil vapor.

Failure mode open means you don't build full boost. Failure mode closed means you could cause the early demise of your turbo. It is $36 well spent for the piece of mind, also check out the vacuum lines as many have found kinks and/or holes since the factory really should have installed a 90 degree elbow in them.

docwyte

Lol. You base that on what? Where are all the threads with people complaining that the valves are failing/have failed?

There aren't any. Simple answer, they don't go bad very often. When they do it's pretty obvious and they don't cause larger issues when they do go bad.

I have over 130k miles on mine and they're fine. These are far more robust than the early VW/Audi ones from 15 years ago....

nodoors

There are many threads just on this Porsche forum about people changing diverter valves and stating that their car runs much stronger or people solving issues with their car not being able to build or hold boost. If you look further out to VW and Audi forums where these same diverter valves are used on almost the entire family of cars with turbos from passats, to bugs, to TT's, to RS6's, you will find many, many cases of them failing.

https://rennlist.com/forums/996-turb...ter-valve.html
http://www.passatworld.com/forums/vo...going-bad.html
http://www.audizine.com/forum/showth...alve-Going-Bad
https://www.google.com/#q=710p+diver...fail+porsche&*

Wrong. You just can't say that so matter of factly because it is a complex issue. Although in the vast majority of cases the failure mode is open (which basically just means reduced power output and a little higher AIT), the entire reason they exist is to attenuate compressor surge when the throttle body plate is closed and the turbos are at full tilt. They reduce spikes in boost in the plumbing which will reduce the chance for boost leaks and the turbo from experiencing unfriendly situations with increased heat and rapid rpm changes from max level.

There are many threads of people chasing boost leaks and even some reports of cracked turbos. Can you prove that none of those were caused by compressor surge?

If you are so confident diverter valve failure won't cause any damage, why don't you just remove yours altogether and plug those three hoses to prove it?

Clearly you are a better engineer or scientist than the rest of us since you think one data point proves something. Why recommend to him NOT to check something if it is known to be a possible failure point on a 10+ year old vehicle he is trying to baseline?

The parts are cheap and if he doesn't want to spend the money on new updated ones he can always test the existing ones with methods written about in the threads I provided above to make sure they are good. OP, while you are in there you might want to check the green o-rings that seal the tubes between the intercooler and the turbo. They also tend to get brittle and start failing at this age, especially on the oily driver side.

docwyte

Diverter valves get blamed for everything. They're rarely the issue, but people like to spend money on shiny things.

Oem valves are cheap, if it makes you feel better to replace them by all means do so. However they don't go bad that often on cayenne's.

nodoors

More old-***** (loose and saggy) information...

10 years is a long time to expect any of the plastic or rubber things under the hood without much thickness to keep their poop grouped.

mudman2

II agree with most things mentioned. You said you changed all bulbs, Bi-Xenon also ?