Sudden engine noise w/ misfire codes [audio attch]

[Matt Richards]

[Background info]
2006 VW Passat 2.0t
91k Miles
Tiptronic AT
All routine maint followed, Oil is due to be changed in 5k miles (by VW guide) or in the immediate future (my standards).
Recent work done:
Coolant flush and fill (Royal Purple Coolant additive used) VW G12 Authentic Coolant used
Thermostat, heater core, and blower motor replaced
Acc Belt and tensioner nearly brand new (a few K miles since replaced)
Running Liquimoly Tech3000 oil and MANN filter
All new OEM motor, tranny, and pendulum motor mounts
Installed ECS dogbone insert
Nuespeed CAI installed (replaced w/ stock engine cover/filter and no change)
3″ downpipe + Hi flow CAT installed.
Rev D DV installed (Upgraded OEM version)

Regularly add ethanol treatment @ gas refills (measured by instructions w/ chemist supplies measuring cup)
Run ONLY 93 octane fuel
No oil additives used
Checked Ignition coils and spark plugs and are perfect for the mileage they’ve seen
Pulled manifold to look @ valves & injectors, some carbon buildup but nothing near what u’d expect to see @ 91k miles.

So otw home a few days ago I had to make a fast pass around a drive that pulled out in front of me. So I switch to S ‘Sports’ mode and put maybe ‘2/3’ throttle down. Once shifted back into D ‘Normal’ mode and accelerating back to speed after slowing under speed limit I start getting engine power loss and my MIL start flashing a yellow engine light. So I limp home and grab my trusty code scanner and get ‘General Misfire’, ‘Misfire Cylinder 1 and 3’ engine codes. After letting the engine completely cool down I try a cold start. It starts up just fine, but now I have a clanking sound coming from the engine. I have not driven the car since, due to concern. I have 2 videos uploaded to youtube of the noise @ temp and at cold crank. I’m having a hard time determining if I’m dealing with rod knock, piston slap, lifter tick, or valve noise.

I’m adding the 2 video links so you can hear the noise, hopefully there’s an engine whisperer out there, I’m not @ that skill level to ‘hear’ the problem out.

Better Video
1st video

Thanks for anyone who takes the time to read, watch, and help out. FWIW I do have an aftermarket extended warranty w/ I’d say better than average coverage, but I’d like to have a solid idea what the issue is b4 involving them so I’m not stuck w/ hours of diagnostic and labor fees in case it’s not a covered item.

Topic

[Daniel]

Unfortunately it sounds like it could be a rod, valve train chatter, a water pump, alternator,power steering pump,smog pump, ac compressor clutch, or even just an exhaust manifold leak.
If it’s piston rod noise it should (but might not) change a little when the engine warms. You might (or might not) see a change in oil pressure too (if you have an oil pressure gauge).
I would start by getting a mechanic’s stethoscope or a long screw driver and listening to each components individually. Don’t assume it’s the engine. Keep in mind that the accessories spin at the same rate as the engine, so it could be something simple on the outside of the engine.

[Dutchie]

I dont what to be kinda rude, but i have heard this noise before, and i was every time a problem whit the oil supply. Are you using the proper oil? Both the grade and VW grading? is the pressure ok, is the oil level ok? Does the eninge use any oil?

Is it a 2.0 T or a 2.0 20V T, any a engine code would help a lot to determine what kind of oilpump is on this engine, since there are some that are know to fail.

[Daniel]

I’m not saying it’s not engine noise, but if you assume it’s engine noise you may overlook something. Never go into a diagnosis looking for a specific problem. Collect all the information you can and let the evidence bring you to a conclusion. Don’t let a preconceived notion alter how you interpret evidence.
I will admit I don’t work on VWs frequently,but proper diagnostic procedure is the same for pretty much every car.
I’m not trying to sound like a “know it all” or say that anyone’s opinion is wrong, but keep an open mind and find the problem in a logical manner.

[Dutchie]

I know, every one has there own way to do his diagnostics, online we can only point out the commenfaults.

Here you can see a commenfault on the B6, the oilpump is drivin by a hexagon, yes the same size every mechanic and tech has in there toolbox 😉 . THese wear over time and turn round, causing the oilpump to lose pressure, offten the pump will pump just enough that the light will stay off, but the bearings are well, gone, same goes for the crankshaft :unsure:

[Matt Richards]

Thank you everyone for so many replies with such good information. I’d like to respond to the questions asked.

It’s a 2.0T Turbo engine BPY engine code, I use Liquimoly Top Tech 4200 VW certified oil, @ the maintenance handbook weight.
I do not have an oil pressure gauge in the car.
The car does use oil, but that is common for a B6 2.0T FSI engine, I check the oil level @ every fill up and top off when needed.
The car is a tiny tiny fraction lower than 100% full on oil, like 97% full ATM.
I did the rod knock screwdriver test and did not hear any knock, but still don’t rule it out as it may have issues down there, but the top engine noise may drown out any indication while the primary issue is going on while running the engine.

I have noticed the noise does lessen once the car reaches idle. However the ‘intensity’ stays the same, it just slows down and is drowned out a little from the accessory belt and timing belt noise I have.

Thankfully I do have an extended warranty and all of your input and what I have been able to verify myself (tore down to the valves Sunday and today), I’m confident the issue and any contributing issues will be well covered since the warranty actually includes whole engine, accessory part, and even a full timing belt service (including water pump).

I am curious to see if the issue comes from the oil pump, I hadn’t given that much focus, but would make a lot of sense as a cause of the major breakdown. I was focused on valve deposits building up so much they make contact, the fuel supply, then the noise started and everything changed.

I’m having the car towed to a top notch euro indie repair shop, hoping they tell me what I want to hear (the truth) and do a complete job or I’ll have to take it down the road to the stealership, (atleast they have outstanding reviews),

I’m hoping while it’s @ the shop someone can find the cause of my hard shift issue shifting up from 1-2 gear. The last shop (a VW dealership) that actually gave a diagnosis said it needed a whole new tranny + VB. (AND YES, my warranty would cover the whole repair).

If everything goes my way, I could be looking at a nearly new car, upper/lower engine parts, timing, crank, drivetrain, AND tranny. If that’s the case I’ll be dancing for EVER!

[Matt Richards]

Ok, so the mechanic says it’s engine sludge, on a scale of 1-10 he says it’s near a 5. Their recommending a oil sludge treatment and a new oil pickup tube. I will pay for them to clean the oil pan, since I can’t do that @ my APT complex.

My question is this:

Does anyone have any experience with cleaners like Auto-RX, Marvel Mystery Oil and Motor Medic for cleaning sludge? The mechanic was confident that it’s not ‘past that point’ and would respond to cleaners, flushes, and additional oil changes.

Also since the B6 Passat has a poor EGR and PCV design, would that contribute to sludge build up? Since I’ve owned the car I’ve used MANN filters, Liquimoly SuperTech 4200 oil, and Motor Medic prior to the oil change. It has been done on a 5k schedule since I’ve owned the car. The first few oil changes were done @ Express Lube using MANN filter and Royal Purple full synthetic oil.

This is where I’m needing advice, everything else I had issues with is covered, but the warranty company is claiming neglect on the sludge and denied the repair. I’m arguing back that since I’ve owned the car it’s been maintained better than VW service recommends. I’ve never had any mechanic or shop even say the word sludge. So, there must be a reason for the sudden build up or release (break up) that’s causing these issues. Any help or insight would be great!!!

What I am thinking ATM is doing an aggressive motor flush w/ Seafoam and Motor Medic, conventional oil (cheap, but quality oil), FRAM oil filter. Then after 2 flushes, doing a heavy sludge treatment with Auto-RX, using Rotella T oil and FRAM filters.

[Auto-RX treatment]
2 bottles added after completing the flushes, adding oil and driving 300 miles.
Drive 1500 miles or so and change oil filter (FRAM Filter)
@ 3000 Miles do a full Oil + Filter service, Add 1 bottle Auto RX Treatment and use my usual Liquimoly Tech 4200 + MANN FIlter.
Drive till next scheduled oil change (5000 miles) and start a Motor Medic flush prior to oil change, then maint with 4 OZ of Auto-RX for the next 10K miles of oil changes.

I’m thinking after cleaning the pan and replacing the pickup tube an initially aggressive approach will breakup and circulate (filter) some of the layers of sludge. Then once the larger portion of sludge has been broken up and drained, a ‘drivable’ sludge treatment (long term) process will remove the residual sludge, prevent new buildup, and eventually restore the engine to a cleaner, better state. All of this w/o having to have done or figure a way to DIY manually clean the buildup in the engine.

[Dutchie]

Slugde can come from a few things, wrong type of oil, mixture of diffent type of oils, also engine coolant (white), or a problem whit the crankcase ventilation system. The crankcase ventilation system needs replacing when dealing whit lots of oil consum. Incl engine software upgrade and the cranksealents.If this wont solve the isseu the engine needs replacement.
The 2.0T FSI needs to have 5W30 whit a ACEA C3 (or beter) coding and a VW 504.00/507.00 coding.

Drop that oilpan, and clean it out, you wont flush it out, period.

[Bill]

It seems like you’re trying to reinvent your car. Definitely sounds like a valve train noise. If you have confidence in your “euro” mechanic let them decide the best course of action. Those cars are known sludge makers as the crankcase ventilation system is very poor. I wonder if those German clowns who build those cars will ever get the message.

Now I’m really gonna stir up a hornets nest but I have seen several sludged up engines that have had Royal Purple oil in them but I’m not sure if the sludge was there before the use of that oil. VW recommends Castrol oil for a reason. They know it does the job. I’m sure they spend millions on testing different lubricants for their cars. It’s only my opinion but after 47 years in the trade I’ve seen the results of infrequent oil changes with the wrong oil as well as the recommended oil, especially in sludge prone engines. VW is not the only one either to have sludge problems. Just ask anyone who owns or owned a Chrysler 2.7 v6.

[Author]

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