RS5 Vacuum Leak - PCV Replaced - Low Whistle from Driver-side Intake

[Majorlazer]

Hi All,

I was driving home from work one day and my EPC light came on with a flashing CEL light. Engine got sluggish and it felt like the car might stall - this is while diving 70 on the highway. Luckly I was at my exit and pulled off, parked the car on the side of off ramp and turned it off. Waited a few minutes and turned the car back on and it seemed ok. Then while driving back to my house the engine started stumbling again, pulled into the driveway and turned it off. Checking the codes this is what came up on my OBDEleven:

Misfire Cyl. 1
Misfire Cyl. 6
Random/Multiple Cylinder Misfire
Cylider 6 - Injector Circuit - Fault Code P020600 (intermittent)
Hide Cylinder - Fault Code P130A00 (intermittent)

I did some research and found a lot of folks pointing to a vacuum leak and a faulty PCV. I started the car up and tried to take off the oil cap and noticed a heavy suction on while trying to remove. I'd put it around 8-10lbs of force to get past the suction. So doing some more researching and decided to order the JHM Billet Crankcase Breather Vent Hose Kit to replace my two PCV lines. Installed and started up the car, cleared the codes and it seemed to be running just fine. I did notice a very low level whistle while the hood was popped but didn't think much on it at the time and was just happy to hear my car running again.

Fastforward a week or so and the same thing happened except while on some side road. Stopped again and this time had a solid CEL light and EPC. Took me a while to slowly get my car home and received the following codes:

Misfire Cyl. 1
Misfire Cyl. 3
Misfire Cyl. 6
Random/Multiple Cylinder Misfire
Cylider 6 - Injector Circuit - Fault Code P020600 (intermittent)
Hide Cylinder - Fault Code P130A00 (intermittent)

I popped the hood and did the oil cap check and noticed it still had a strong suction ~8lbs. This time I paid attention to the whistle and tracked it to the mouth of the driver-side intake. I could hear it coming from one of those tiny holes on the intake and you couldn't hear anything on the passenger side intake. So I started removing the intake sections, removed the box with the filter and the sound moved to the exit of the sleeve coming off the throttle body. Then removed the TB sleeve and whistle was coming from within the TB. I started playing with all the vacuum tubes and couldn't get the noise to change. I also did A LOT of adjusting the JHM PCV system with no change to the whistle or suction on the oil cap.

I came back at it with a smoke test that I rigged up myself. Filled the intake manifold and couldn't spot a leak unfortunately.

At a loss I finally removed the throttle body on the driver side where that whistle is coming to see if there was anything wrong with the gasket and also to get a better view at the vacuum lines around that area. While it was really dirty the gasket looked fine. What I did spot were some gaping seams in the intake manifold inlet. These appear to be seams and not cracks but one or two of them look far from a standard seam and wondering if I found the issue. Not sure how many of you have removed the TB before but if someone has can you take a look at these pics and let me know if what you've seen on your car is similar or not? Also as I suspect someone might ask, I pushed open the passenger side and peered in with a flashlight - the same seam is sharp and not gaping like in these pictures.

Appreciate any insights or feedback on this!


RS5 TB Inlet 2.jpgRS5 TB Inlet 1.jpg

[Majorlazer]

Hi All, I repaired the visible gaps in the photos attached with some plastic JB Weld and Hot Staples. Sanded smooth and started up the car. Still have a whistle coming from the driver side throttle body. Checked the oil cap suction and it was still pretty strong but maybe improved? Probably in my head.

Next step is a smoke check with UV oil and a UV light. Hoping if there’s still a leak somewhere I’ll find it!

[hahnmgh63]

If it actually comes down to it and you need a replacement intake manifold, due to some folleys I happen to have two extra intake manifolds. I'd be nervous about using any JB Weld on the inside of the manifold where it could get sucked into a valve or damage one of the rings.

[Majorlazer]

Hey man, thanks for reaching out. I might take you up on that because I had no luck finding any vacuum leak while searching with the UV dye.

I have a few other trouble shooting steps to check out so we’ll see how this goes.

Btw too late on the JB weld. I have that crease filled and hot stapled. Sanded the area down after and the whole thing is looking pretty stable. Mystery where the whistle is coming from.

[Majorlazer]

Hey All,

The smoke test with UV dye didn’t give me any clues.

I decided to pull the IM and get my injectors cleaned with the hope that I could investigate a bit more with the car disassembled.

The big discovery is that the pcv system has sucked A LOT of oil into the IM and that oil has leaked into the valley where it pooled and then further down the engine. Would guess 1QT worth at once based on the area it had to cover.

I’m down to either I’m pulling too much air from the crank case or the free air inlet to the engine is blocked.

Pulling too much air thoughts:
- I’d hate to think the JHM pcv sys I bought is no good but not ruling it out.
- I was also wondering if the throttle body is just not calibrated well, not open enough and the engine is thus pulling more air through the PCV at idle. Would still point to a faulty PCV valve in the JHM product.

Blocked Fresh Air Inlet thoughts:
- if pulling a normal vacuum from the pcv but no fresh air inlet to compensate could this contribute to a high crankcase vacuum? Or does that fresh air inlet not make its way to the crank case?

Last thought, someone said they had a similar issue and maybe resolved it by replacing the “crank seal”. That thread seemed to die off a few months ago so not sure I’ll get a definitive answer back on that one.

Next Steps:
- pressurize fresh air inlet line to see if there’s a blockage
- check out this crank seal replacement to see if that’s something or not
- clean oil off engine
- install cleaned injectors and rebuild
- start the the car and check vacuum at the dip stick
- check vacuum on both PCV lines

Any other thoughts before I put the IM back together?

[hahnmgh63]

Definitely seems like a PCV valve is faulty, that would be my first thought but obviously you have another problem or un-related since you started this journey before you had installed the JHM PCV system. I wonder if you can call JHM and see if they can test the valves and if they have any ideas? Let me know if this link works, pics from a 99k RS5 intake manifold and from a 26k intake manifold. Pretty much these two look the same. 6775 & 6776 are from the 26k manifold and 6777 & 6778 are from the 99k manifold, high miles is a 2013, lower miles is a 2014. https://www.dropbox.com/scl/fo/4gbvc...gwy85c884cev6v

[Majorlazer]

I got the photos and thanks for sharing! So both IM have the same gaps on the driver side - I guess that’s not really any thing to be concerned about. I separated the front and back sections on the upper IM and found oil was leaking from the gasket. I’ll share some photos later. Thinking this gasket isn’t meant to contain oil.

I want to check if both valves in the jhm pcv are pulling the same vacuum from the IM. Figured what’s the chance both valves are bad? But thinking the same thing and will follow up with jhm next week.

Will test it when I get things back together. Fuel injectors won’t be in until Wednesday so this is a late next week effort. Right now I’m slowly carbon cleaning.

Oh and second note, I noticed oil leaks from both valve cover gaskets. Oil all over this engine.. you’d think I have too much pressure and not too much vacuum, weird.

[Majorlazer]

Hi All,

I got my injectors back and they’re looking great! I did some carbon cleaning while i was waiting and repaired the gasket seal between the two UIM half’s where I found the leaking oil. Ordered new seals for the UIM and LIM. It’s all put back together and the car started up nicely after the fuel recharged in the system.

Now back to the vacuum discussion. Had low expectations that anything would be different, and yep, no change. I didn’t find any issues with the vacuum lines or fresh air line. So I checked the vacuum from the dip stick at idle and it was 10 inHg. I read a few places that 1-3 is normal but still not sure if that’s too much or not. I also checked the vacuum pull off each of the pcv lines by removing the billet from the crank case and jamming my vacuum gage into it. Each side reads 20inHg which I’ve read is normal for the IM… but shouldn’t the valve be mostly closed when the vacuum is this high in the IM? I reached out to JHM yesterday and waiting for their response.

I’ve read that there could be an issue with my crankshaft position sensor. I believe this communicates back to the throttle body and controls vacuum in the IM so perhaps that might be a lead.

Lastly I heard back on the other form that someone with a similar issue replaced their crank seal and resolved the vacuum issue. Digging into that now.

I’ll post some pics of the injectors and carbon buildup in my car. I have 99K miles on this car.

[Majorlazer]

Ok here are the pictures that I said I'd share:

Carbon Buildup:

carbon.jpg


Upper Intake Manifold Leak (lower middle fastener)

IM Oil Leak.jpg


Oil Path from UIM traveling to the front of the engine

Attachment 310008


Carbon Buildup on Injectors:

Injector 2.jpgInjector 1.jpg

Checking the Vacuum at the dipstick:

Dip Stick Vacuum.jpg

[Majorlazer]

Hi All,

A few more updates:

Took a bit of driving but I ran into the rough idle again. Shut off the car turned it back on and seemed to be back to normal. Checked the codes and saw the same ones I had before (I had cleared them). Cyl 1 & 6 misfires and a intermittent circuit on cyl 6.

I decided to play around with the fresh air line coming off the driver side intake that goes down to the "valley" or crankcase housing? I plugged it with my finder and the whistle went away. huh? Ok that was a nice discovery. So next I stuck the vac hand pump into the dip stick, read 10 in/Hg, then plugged that fresh air line and guess what, the vacuum increased to 13 in/Hg. Cool, some correlation here. I opened the repair manual and sought out that line to see where it actually went and how it related to the whole system. Interesting what I found - the repair manual calls it a crankcase housing "ventilation". Huh. Well mine is sucking air in and definitely not ventilating. I have a hunch that air is escaping the engine somewhere it's not supposed to be escaping from. Thinking back to what I found in the other form, I could have a leak at the crankshaft seal. The oil leak I found might be masking the oil leak you'd find with a failed seal. From some searching I certainly found forms where folks were correlating a high vacuum with a crankshaft seal. Anyways I'm venturing further into that theory and will look for a way to test it out and then maybe pull the front end off the car and change it out.

Here's a clip from the manual of the ventilation hose and also crankshaft seal:
crankcase ventilation hose.jpgcrankshaft seal.jpg

[hahnmgh63]

That hose should have suction and not pressure. It is for Fresh air to enter the engine. The Blow by gasses come off the valve covers and go to the oil separator, some blowby with oil is supposed to be dumped back into the crankcase and some ends up in the Intake and gets reburned/burned. Not all Crankcase gases are piston blowby, some are from the fresh air entering. Others have had a squeal from the PCV system.

The crankcase ventilation system also includes a
crankcase breather. Air is drawn from the air filter box
and flows through a check valve into the crankcase at the
inner V. The mixture of fresh air helps ensure a reduction
of water and fuel mixture in the crankcase from the blowby
gases.
A damping chamber is located below the check valve in
the engine block. This helps prevent check valve flutter
and eliminates noise.

Read Post #12 in this link from SMAC
https://www.audizine.com/forum/showt...-replaced-Help!

[Majorlazer]

Hi All - i eventually went for the crankshaft seal and had some success. But still a few open questions - story below and skipping over the stuff that followed closely to the manual.

First off removing the front bumper is not a big task but the radiator is rough.. There is a the large coolant hose connecting to the bottom of the radiator that is hard to access if you follow the Audi manual and is extremely hard to remove and install. It has a plastic couple and a clip to secure it in place. You can’t wedge a pick under it, spray wd40 and loosen the parameter like the other coolant hoses around the car. Instead I bought a wide flathead screwdriver and worked around the exposed areas until I could yank it off. Putting it back on was a ridiculous task. Again little access in that area and it doesn’t simply slide on. After 2 hours of trying i resulted in putting a large zip tie on the couple that held a chain of zip ties to either side (driver side exposed by removing the bracket/mount that holds the oil cooler and the other side fishing out at the bottom of the radiator and plastic frame it mounts to), bracing against the radiator and pulling with both hands. That stupid setup did the trick.. there’s probably a professional way to do this.

Next, the refrigerant return line connection has a fastener that was rusted through and shears off while I was removing it. Not enough room for two nuts trick, so I removed the remaining rusted area and cut a slot for my large flathead with a dremel. It was ceased in there and ultimates the metaled failed around the slot I created. Took a flame and vice grips to get the sheared off bolt out of there. (Pic below of the situation for those interested)
72316510867__4A640883-0D06-4723-B2BD-8AAA8553629B.jpg

Then the brittle plastic line going from the top of the radiator to the overfill tank broke at the connection point to the radiator. The o-ring and plastic nozzle that slides into that outlet had ceased together. I carefully picked it out of the radiator with a small pick (dental pick was too flimsy for this). I cheaped out and used some coolant hose from autozone to reconnect this line. This is the second one of these small plastic coolant hoses that have fallen apart on me while doing repairs. I guess the heat cycles over 100k miles makes them fragile.

Ok, now onto the seal itself. I was adamant on not using the screw and pliers method out of fear of damaging the crankshaft. I bought the amazing hook/leaver tool, and also this Amazon duel hook seal puller tool that is like a revers clamp and pushes on the crankshaft and pulls on the seal. I SHOULD HAVE bought the OEM tool for removing the seal because both of these cheap tools were useless. I eventually used the screw and pliers method to get the damn thing out and DID scar my crankshaft. I had the OEM tool for the install and that went wonderfully.

I had to do this seal install twice:

First time I lightly sanded the scaring I created during the removal, installed the seal dry and got the car mostly put back together. Started the car and guess what, the noise from the fresh air vent was gone and no excessive vacuum on the oil cap! I was low on oil that I lost during the oil cooler removal and went ahead and did an oil change. Stated that car again. Started refilling the refrigerant and when about complete with the first can I heard a “sigh” from the engine and the noise came back. Checked the oil cap and yup excessive vacuum again. I turned the car off and spent the rest of the weekend with the kids. That week I read about seals, crankshaft scaring and wet/dry installing. In general people are saying any scaring, rotating at 1000s of RPMs will be an issue for that seal (makes sense). Others were also saying a dry seal might struggle on the first few starts. So I had a few things to attempt.

I decided to give it a second try.

Second time was a lot smoother. When I got the seal out I went at the crankshaft with 700 grit around the full circumference until the scaring was mostly gone. I then went up to 1000/1500/2000 and finished with polish. I removed the polish and was careful to make sure the sanding didn’t fall into the engine at the gap at the bottom of the crankshaft. I have this oil for metal/seals that I put on on the crankshaft and seal (bought a second seal for this) to help it slide on and ensure the first start was smooth. Put the car back together (lower radiator hose was just as hard the second time around) and started up the car. Noise is fine and the vacuum is normal.

I’ve driven the car for a week now with no issues. Success!!! Why does the crankshaft seal have anything to do with the vacuum in the heads?

Wait.. so there’s more. When I changed my oil I did the min and my min oil light came on. It said I could add 1.25 liters. I added 1 liter and the car then said I was at Max. Ok. Sound came back along with excessive vacuum at cold start! What?! Then after driving to the office the sound and excessive vacuum were gone. It’s been good for the last few days but not so confident that the fix is complete with that reoccurrence at cold start I experienced. Also it was after the car say for a few days. Not sure how that could have played into it.

[axnjaksn]

Bump, did this ever get fixed for good??

[Majorlazer]

Hey Axnjaksn,

The vacuum issue is back. Both times I removed my oil cooler and replaced the crankshaft seal, the excessive vacuum went away. Then added oil and it came back. If I take off the driver side intake that connects to the throttle body, expose the fresh air inlet, and plug/unplug it with my thumb, the system seems to unplug itself and I don’t have the excessive vacuum or sound any longer. So my guess is, replace that fresh air line. If that doesn’t help I’ll pull the oil pan and try investigating from the underside of the engine.

Still a mystery..

[R32sSayBwaaa]

What a sad thread. I feel for you man. I could only imagine experiencing this emotional rollercoaster.

Hope you got it figured out! Let us know what came of it.