PCV install with intake manifold in place?

**Seattle squash** · 02-14-2016 09:32 PM

Found some DIY info on the b7 rs4 but it was not clear, assuming I found the right one, if it could be done with intake on? Anyone have any good info on that? If so it would be great, or if there is another DIY out there for the RS4.

Thanks.

**AWD Addict** · 02-14-2016 09:40 PM

I'm interested in this as well. Out of curiosity, why are you planning to replace the PCV?

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**Seattle squash** · 02-15-2016 05:29 AM

To see if I can eliminate the 1 court top off mid oil change interval. And if I take the oil cap off while car is running there is major vacuum and car stalls, which I understand is a sign of failed PCV correct?

**FWP!** · 02-15-2016 11:19 AM

Originally Posted by Seattle squash

To see if I can eliminate the 1 court top off mid oil change interval. And if I take the oil cap off while car is running there is major vacuum and car stalls, which I understand is a sign of failed PCV correct?

Yes, that means the rubber diaphragm has failed.

The PCV valve can be removed with the IM on. Take the intake elbow off, the PCV cross over tubes, throttle body, move the brake booster hose up out of the way, loosen the passenger side SAI valve which is bolted to the rear timing cover which will allow you to uncouple and push the SAI tube back out of the way so that you can then start removing both t30 screws that bolt the PCV to the intake manifold. After removing both bolts, you can get the PCV valve removed from the intake manifold, but don't pull it straight out, you have to lift it up enough where you can remove the oil drain back tube that is connected to the bottom of the PCV.

**Seattle squash** · 02-15-2016 01:39 PM

Originally Posted by FWP!

Yes, that means the rubber diaphragm has failed.

The PCV valve can be removed with the IM on. Take the intake elbow off, the PCV cross over tubes, throttle body, move the brake booster hose up out of the way, loosen the passenger side SAI valve which is bolted to the rear timing cover which will allow you to uncouple and push the SAI tube back out of the way so that you can then start removing both t30 screws that bolt the PCV to the intake manifold. After removing both bolts, you can get the PCV valve removed from the intake manifold, but don't pull it straight out, you have to lift it up enough where you can remove the oil drain back tube that is connected to the bottom of the PCV.

Great, thanks for that feedback. So would you say about an 1/2 hour job or so? Thanks and got a new one ready to be installed.

**highPSI-S4** · 02-15-2016 04:21 PM

Originally Posted by Seattle squash

Great, thanks for that feedback. So would you say about an 1/2 hour job or so? Thanks and got a new one ready to be installed.

It's a bitch to get to if you have sausage fingers lol! I have taken off/on twice and its a little bit of a pain. I'd say 45mins is about right haha!

**evolution2147** · 02-15-2016 09:44 PM

Originally Posted by Seattle squash

To see if I can eliminate the 1 court top off mid oil change interval. And if I take the oil cap off while car is running there is major vacuum and car stalls, which I understand is a sign of failed PCV correct?

What oil are you running? I have been using mobil1 on my s4 and rs4 and have always had about 1-1.5qt loss and the yellow MIN oil light would always come on about 3k miles into the change. I just switched to castrol 0w40 and am at the 5k mark and have had no issues yet.

Also every VAG car I have seen seems to stall out when the oil cap is removed. Not too sure why but i think its normal.

**Seattle squash** · 02-16-2016 05:21 AM

Hmm interesting. Pennzoil ultra/platinum 5w-40. Similar for me except I just check and add slightly at 2.5k and never have the light come on. Thanks.

**Al Sline** · 02-16-2016 12:56 PM

Hi Seattle, i seem to have the same issue with my PCV... Is it a fact the the vacuum leak is directly associated to a defective PCV.... I do blow out a significant amount of smoke only when i start my car in the morning so i was thinking of eventually swapping it out....but after checking the oil cap my car definitely stalls...:(

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**dufferdude** · 02-16-2016 01:42 PM

Originally Posted by Seattle squash

Great, thanks for that feedback. So would you say about an 1/2 hour job or so? Thanks and got a new one ready to be installed.

What's the part number? Ty

**WinterRunner** · 02-16-2016 01:42 PM

I have to try this out.... What is the mileage we tend to see the failure?

**highPSI-S4** · 02-16-2016 01:45 PM

As per JHM website.

OEM Part Number is: 079103464F or 079 103 464 F

**JimmyBones** · 02-16-2016 01:58 PM

Originally Posted by WinterRunner

I have to try this out.... What is the mileage we tend to see the failure?

It varies but I would personally do it every 40K to 50K at least.

If it were my car then I would take it apart and clean it or better still replace the PCV every time that I do a carbon clean. However they are pricey at like $250ish.

**WinterRunner** · 02-16-2016 02:37 PM

So my car doesn't stall per se, but it definitely falters some, like lowering the choke on a snowblower or mower. I think I might have this done. Would it stall out within seconds? I took mine off and it was sputtering for 20-30 seconds before I replaced it, but never stalled.

**Al Sline** · 02-16-2016 03:00 PM

Hi winter... Was it tough to turn the oil cap while the engine was running followed by a vacuum sound?

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**CoreyRS** · 02-16-2016 03:31 PM

JimmyBones,

Have you experienced a decrease in oil consumption after replacing a PCV on an S4 or RS4?

**JimmyBones** · 02-16-2016 04:03 PM

Originally Posted by CoreyRS

JimmyBones,

Have you experienced a decrease in oil consumption after replacing a PCV on an S4 or RS4?

Yes on the B6/7 S4s, the RS4s, the low revving 4.2 FSI V8s, and the 5.2 V10 FSI engines. The B6/7 S4s use a different style PCV that sucks as well. The RS4s, low revving 4.2 FSI V8s, and the S6/S8 V10 all use similar PCV valves but the angle of the drain nipple is different.

**WinterRunner** · 02-17-2016 08:10 AM

Originally Posted by Al Sline

Hi winter... Was it tough to turn the oil cap while the engine was running followed by a vacuum sound?

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Yes, I mean it is under vacuum right? Either way I'm having this done, should also help with consumption issues (not alot, only about a quart every 5K).

**koolade9** · 02-17-2016 01:36 PM

Originally Posted by WinterRunner

Yes, I mean it is under vacuum right? Either way I'm having this done, should also help with consumption issues (not alot, only about a quart every 5K).

Our crankcase is not under vac (or very little vac basically). There's a breather from the intake elbow to the valley that flows metered air into the crankcase that then flows through the PCV into the IM. If the PCV diaphragm is torn, it will change the flow characteristics and actually create vac in the system since the breather can only flow so much air. Removing the oil cap introduces unmetered air into the system, and if that PCV is torn, it will take all of that air into the IM, hence the stalling. If your PCV is okay, it will bog a bit, but shouldn't stall. That being said, the idea of removing your oil cap while the motor is running just sounds like a bad idea...hope you don't have any sand/debris around your oil cap.

**WinterRunner** · 02-17-2016 01:44 PM

Originally Posted by koolade9

Our crankcase is not under vac (or very little vac basically). There's a breather from the intake elbow to the valley that flows metered air into the crankcase that then flows through the PCV into the IM. If the PCV diaphragm is torn, it will change the flow characteristics and actually create vac in the system since the breather can only flow so much air. Removing the oil cap introduces unmetered air into the system, and if that PCV is torn, it will take all of that air into the IM, hence the stalling. If your PCV is okay, it will bog a bit, but shouldn't stall. That being said, the idea of removing your oil cap while the motor is running just sounds like a bad idea...hope you don't have any sand/debris around your oil cap.

Well it bogged but didn't stall at all, even after 30 seconds. It is squeaky clean, I make sure of it everytime I add oil. Thanks for the detailed explanation. I think I'm going to have the PCV replaced anyways, as it's higher mileage (near 90K).

**Mistro** · 02-17-2016 02:33 PM

Just to add to what people said, you'll need a pretty slim ratcheting torx bit driver/wrench to get to the screws holding the pcv in.

**CoreyRS** · 02-17-2016 03:27 PM

Good info here guys, thanks all!

**AWD Addict** · 02-17-2016 03:28 PM

Is the test with the oil cap the only way to determine if the PCV is failing? I'm getting smoke at startup but also when I pull away from a long stop light.

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**komseh** · 02-17-2016 04:58 PM

Physical inspection is the best way to determine if your PCV is bad.

The smoke is black, correct? You may have issues elsewhere but ensuring a properly functioning PCV is a good start.

**Seattle squash** · 02-17-2016 10:03 PM

Having it installed tomorrow, and keep you posted on differences in performance/consumption/behavior.

**JimmyBones** · 02-18-2016 09:07 AM

Originally Posted by AWD Addict

Is the test with the oil cap the only way to determine if the PCV is failing? I'm getting smoke at startup but also when I pull away from a long stop light.

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Sometimes I have heard a whirling noise like a leaf or stick stuck in the wind coming from the PCV valve while driving. Usually the radio and heat/AC has to be off to hear it though.

**Seattle squash** · 02-18-2016 08:35 PM

So new one installed today. I know the oil cap test is relevant now as it used to stall right away once removed. Now bogged down for a second and then stabilizes and runs smooth. Cool, will watch the oil consumption and see if cold starts are less smoky. Reference point for me; is 1 quart per 5k. I will update.

**WinterRunner** · 02-19-2016 07:30 AM

So it bogs but then sputters back to normal idle? Hmm then I suspect mine is not done for, but on it's way out...

**Seattle squash** · 02-19-2016 09:05 AM

Yeah huge difference for me. Just a small hesitation/bogged down for a second and then perfect. Less suction too. Before crazy suction and then car completely died in a second.

**wednesday** · 03-07-2016 10:50 AM

It looks like it's my turn to have this replaced now. I have a lot of suction when oil cap is removed at cold idle. Car bogged quite a bit once cap is removed but it didn't stall.

Is this really less than an hour of a job? Do you have any lessons learned or gotchas from this? Thanks!

**MattboyR32** · 03-07-2016 03:02 PM

got to try this test!

@seattle squash, how much time did your mechanic charge to change the PCV?

**your daddy** · 03-07-2016 03:10 PM

Originally Posted by wednesday

Is this really less than an hour of a job?

LOL. throttlebody off, all pcv hoses, purgevalve with hoses, SAI hose removed, throttle boot, misc hoses, slightly easier with the jhm coolant bypass. and the btch is the oil drain hoses squeeze clamped on. good luck.

**Seattle squash** · 03-07-2016 04:24 PM

Originally Posted by MattboyR32

got to try this test!

@seattle squash, how much time did your mechanic charge to change the PCV?

He charged me $100 (an hour or less), well worth it to me, especially with a cluster of a back!

**your daddy** · 03-07-2016 06:28 PM

Originally Posted by Seattle squash

He charged me $100 (an hour or less), well worth it to me, especially with a cluster of a back!

any other work done at the same time? carbon clean? flap work, etc?

**MattboyR32** · 03-07-2016 07:08 PM

Wow. Ok cool. I did the oil cap test and the engine really struggles to get back to idle. It's going on the list of stuff to do at next service.

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**Seattle squash** · 03-07-2016 09:10 PM

Originally Posted by your daddy

any other work done at the same time? carbon clean? flap work, etc?

No just PCV, CC about 7.5k ago, flaps intact but coded out to be safe, Intake plates removed when new intake manifold "spacer" was added.

**dturn37** · 03-08-2016 11:00 AM

Wouldn't this throw a CEL or a fault code if it was faulty or going bad? I was under the impression the only real way to test for a vacuum leak or a faulty PCV valve was to run a smoke test. I've always had some suction when pulling the oil cap off at idle and it would struggle but never stall. Would this also hurt gas mileage too?

**wednesday** · 03-08-2016 11:22 AM

Originally Posted by Seattle squash

No just PCV, CC about 7.5k ago, flaps intact but coded out to be safe, Intake plates removed when new intake manifold "spacer" was added.

What was your before/after impression once PCV was replaced?

**Seattle squash** · 03-08-2016 04:45 PM

Originally Posted by wednesday

What was your before/after impression once PCV was replaced?

Less smoke for sure, especially on cold-start. Within a month or so I will update on oil consumption, once I have a good point of comparison.

**Seattle squash** · 03-30-2016 05:49 PM

So its been 2500k and would say that I am about 40% less in oil consumption based on my dip stick reading. So pretty happy to see that, and mine was pretty bad/failed. Just wanted to update upon check yesterday. I am never getting the oil dash warning but used to be a quite a bit lower on the dip stick at this point. Same oil, same driving style etc.