I’m looking for some technical insight regarding my 2014 Cayenne GTS (4.8L V8) with 81k miles. I recently hooked it up to a scanner to check the health of the timing system, and the Camshaft Deviation values at operating temperature (idle) have me concerned:

• Bank 1: +7.1°

• Bank 2: -0.3°

I know Porsche generally considers +/- 6° to be the "limit," so Bank 1 is officially out of spec. What's striking is how perfect Bank 2 is, which makes me think this isn't a simple case of the main timing chain stretching, but rather something localized to the passenger side (Bank 1).The car seems to run well.

Questions for the group:

1. With Bank 2 being nearly zero, is it likely a failing guide rail on Bank 1 specifically?

2. Could this be a failing VarioCam solenoid or actuator on that bank rather than a mechanical timing failure?

3. For those who have seen +7°, how much "time" do I likely have before a P0016 code or limp mode kicks in?

4. Should I be looking at the Camshaft Controller Bolts (AH08 recall) even though this is a 2014 model?

I'm planning to pull the oil filter this weekend to check for the dreaded "orange plastic" bits.

Any advice on diagnostic steps I should take before committing to a major teardown would be greatly appreciated!

 

Sounds like the middle chain guide has failed. I've seen other reports of bank one being off by 12 degrees, so maybe it hasn't fully disintegrated yet, or maybe the broken chunks from the plastic guide surface are still wedged between the metal frame of the guide and the chain itself somehow, causing the deviance to not be so large. If you look through the oil fill opening towards the center you can see the top of the chain guide. If you only see metal and no plastic you'll know you have a problem, but even if you still see plastic I'd suspect a problem. I think several people have continued to drive with their guides further disintegrated than yours. I bought my 2012 ctt after the PO drove for 1.5 months with a disintegrated guide, and I drove it that way for a week or so, but it's parked now while I wait for parts and time to tackle the repair.

 

I tried to poke with my borescope towards center and I see this orange/brown plastic piece. Not sure what to make out of it. When you say the middle guide, are you referring to the guide on the main chain (crank-to-center) or the bridge guide between the banks?

 

Seeing an orange-brown plastic piece is good news, provided it's still hooked onto the frame of the guide. I'm talking about the guide for the main chain that runs between the cylinder heads. The chain travels from the cylinder with the oil fill cap (I'd say passenger side cylinder if I knew you were in the US) towards the other cylinder head. The chain moves clockwise when looking at the front of the engine. Between the heads is a large, horseshoe shaped guide with an orange-brown plastic liner piece that the chain rides on. That plastic piece can fail by breaking up into small chunks, so that the chain ends up rubbing on the metal frame of the guide. When the plastic liner is gone the length of chain needed between cylinder heads is shorter, causing the mismatch in cylinder timings.

I'm having a hard time orienting myself with your picture. There are 3 main guides that are plastic lined. You want to look directly horizontal, towards the engine centerline, across the top of the sprocket+chain right there inside the oil fill opening. You should see the start of the liner for the big chain guide where the chain starts it's downward path to get over to the other cylinder head.

 

Here is a video I made, I tried to follow the chain path down towards the center of the engine:

 

Your guide is toast - it has no more plastic on the visible area.

 

Yeah, your liner has failed. At :09 the metal piece that the chain is touching should be shrouded in plastic. It should look something like this, but since your plastic liner is missing you are only seeing the metal part supporting where the plastic hooks over.

 

What a bummer! This shouldn’t happen on an engine with 80k miles. I don’t think I can DIY this, is it 20-30 hours job?

 

I’m wondering how one can guarantee that all plastic bits feet removed from the engine? It’s possible these plastic bits can be anywhere in the engine, not only in the oil pan. Am I overthinking this?

 

Based on where the front timing cover sits over the pan, most small pieces of plastic should fall right into the pan.

 

I’m compiling a list of “while there” items to replace or inspect. My 2014 GTS has 81k miles, here is a list I created. Please help me figure out if anything is missing and if anything might not be worth doing.

1. Timing & Critical Engine Components

• Replace entire timing kit (main chain, all 5+ guides, and tensioner)

• Camshaft Controller Bolts: check to see if steel bolts installed if not REPLACE with updated steel versions

• Oil Pan: Drop and clean the oil pump pickup screen of all plastic guide debris.


2. Cooling System

• Water Pump: Replace (metal impeller preferred).

• Thermostat: Replace

• Front Coolant Pipe (948-106-069-21): Inspect aluminum for pitting; replace gaskets

• Rear Coolant Pipe (958-106-145-04): Inspect for "weeping" at the hose connections near the firewall.


• Top Vent Line (948-106-026-22): Replace brittle plastic line.

3. Accessory Drive

• Serpentine Belt: Replace

• Belt Tensioner: Replace

• Idler Pulleys: Replace

4. Gaskets & Seals

• Valve Cover Gaskets: replace

• Spark plugs gaskets : replace

• Front Crankshaft Seal:replace

• VarioCam Solenoid Seals: replace

* Vacuum pump seal : replace

5. Electronics

• VarioCam Solenoids: clean and bench test, if worn replace

 

Oil cooler - replace gaskets
Metal coolant pipes - pin and seal
Vacuum pump - inspect and reseal/replace if necessary
High pressure fuel pump - inspect and reseal if necessary
Inspect all coil packs for cracking - replace if necessary
Spark plugs - replace if old
Inspect cylinders with borescope for scoring or carbon buildup
Intake valves - inspect, clean if needed

Some things, like coil packs or serpentine belt can maybe be left until they fail because they aren't that big of a job later, but anything likely to fail that requires valve covers or intake off, like the vacuum pump, is probably best addressed while you're in there.

 

My buddy has 2013 Cayenne Turbo S, I asked him to bring it by for me to check his guides, and what you think? His are broken too but not as bad as mine, deviation on bank one is 3.125. I think this problem might be widespread - lots of people driving around with a broken guide without even knowing - it’s a ticking time bomb!

 

So, I was able to sneak my camera deeper and snap this picture, plastic guide is completely missing!!! I got metal on metal situation. I don’t know how this car can even run like this - no CEL, no chain slap noise, absolutely zero symptoms.

Either way, I’m planning to bore scope the cylinders tomorrow to rule out any scoring. I want to be absolutely sure before investing any more money into it.

What type of socket will work best to turn the engine? I asked Gemini this question and it told me to use 27 mm 12 point socket. Is that correct? I briefly looked and it appears to be a tight space.

 

Here is a how-to regarding inspecting the chain guide and what to look for: