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Author Topic: Pretty bad PCV…  (Read 1513 times)

Offline SANDEGTI

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Pretty bad PCV…
« on: August 09, 2022, 04:54:19 pm »
Hello everyone, decided to have a little tear down today and checked over a few things and managed to get the PCV off and take a little look. I didn’t quite expect the gunk and oil as the car only seemed a little lumpy, nothing serious but on inspection it should be running like absolute sh*t!! Ordered a new one including the gasket as would rather be safe and not have to do it again for a while.

Would definitely recommend checking it if you haven’t for a little while, we had no obvious symptoms apart from a slightly rough idle. I am no expect but with 20 minutes and a couple of basic tools, it’s very simple to do.  :grin:

















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Offline ROH ECHT

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Re: Pretty bad PCV…
« Reply #1 on: August 11, 2022, 02:55:00 pm »
All of that buildup comes through the tube from the primary oil separator. Which is built into the top of the oil filter assembly. Chances are its oil filter assembly is also in the process of clogging. That tube connects the two. The secondary oil separator is built into the rocker cover. You may consider giving all a bath in some petrol and replacing all related seals.

Use a VW 502.00 approved - full synthetic 5W40 oil (5W30 502.00 approved if 5W40 isn't available) and change it at no more than 5k miles.



« Last Edit: August 11, 2022, 03:16:50 pm by ROH ECHT »
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Offline SANDEGTI

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Re: Pretty bad PCV…
« Reply #2 on: August 12, 2022, 04:48:06 pm »
Thank you so much for your comment, gutted I only just saw this as I had already ordered a new PCV and fitted it, new gasket too. Right, the car sounds and feels a bit better since doing so but it's still not right. It backfires a little when you floor it and there's quite a noticeable hissing sound that seems to get worse. The engine feels like it's being overworked but definitely feels smoother since.

What do I need to do next? Honestly, I'm not experienced with cars at all so I'm a total newbie. I'm more of a hands on type of guy. Shall I clean the connecting hoses or just replace them?

EDIT: I forgot to mention, there was an air leaking kinda sound when the car has just been driven and the noise usually lasted about 20 minutes after turning it off. It doesn't seem to be doing that now but I'll monitor it. Not sure if this will help lead to diagnosing exactly what the issue is.
« Last Edit: August 12, 2022, 04:49:41 pm by SANDEGTI »
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Offline pudding

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Re: Pretty bad PCV…
« Reply #3 on: August 13, 2022, 10:19:27 am »
I hate to think how bad a 15 year old primary oil separator looks inside!  An absolute arse to get to though, but those restricted passage ways are like blocked arteries causing high blood pressure, which can result in a bit of blue smoke.

A lot of hard to diagnose air leaks can be caused by the rocker cover itself. See that section with the green line in the drawing?  It's a chamber ultrasonically welded, which can break apart over time causing a vacuum leak.  That's a last resort though as a new rocker cover is about £150+VAT.  Well, it was a few years ago before Brexit, but god knows how much now!



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Offline ROH ECHT

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Re: Pretty bad PCV…
« Reply #4 on: August 14, 2022, 04:51:34 pm »
Given the amount of buildup where the tube connects to the PCV from the filter assembly, I imagine there is much more at the lower end of the tube, and inside the primary separator. You can clean the tube when removed, but the separator would need to be removed. And still, after soaking it, you wouldn't know how clean it is inside for it being a sealed unit. I would just replace it. For the need of new seals on the filter assembly and cooler, I replaced my filter assembly (seals were included). But each to their own.

As said, when the crankcase venting becomes clogged, it can develop air leaks from the pressure forcing its way out of the crankcase.

"What to do next"...in my opinion is (some of this is in assuming it is all foreign to you): some cleaning of the crankcase venting bits as discussed, drop the oil pan/sump and clean the oil pickup screen and clean the pan, replace all leaking seals, look into self-checking the cam follower, checking the timing chain and tensioner health, and studying some general TLC practices of others. Whenever you have something of concern or if you are simply interested in something...search for "MK5 GTI ______" ←*fill in the blank* and read threads/topics. Lately, it seems car manufacturers build cars for the consumer mindset that they are disposable. And only intend for the car to last beyond their warranty periods or to last the period of time people own a car before replacing it. Ours didn't even include the cam follower in any of the service intervals as an inspection in the owner's manual - service interval booklet.
« Last Edit: August 14, 2022, 05:29:06 pm by ROH ECHT »
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Offline SANDEGTI

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Re: Pretty bad PCV…
« Reply #5 on: August 25, 2022, 08:18:56 pm »
Thank you for your response, next time I need to mess with the car I will get in there and clean it and do a bit of research! In all honestly I used to be afraid of messing with cars until I got this one, but had to save money and time with work. Sorry, I didn't mean I wanted to know what to do next in that respect, I've done all the major and common faults so far. From the top of my head I've done the chain, belt, sump, cam follower, plugs, coils, pcv, diverter (was a different animal), camchaft valve (cant remember exact name) and a full service. Not sure what will go wrong next but there's always something... probably injectors. Could they still be the original ones for a 2005 137k? Probably the clutch too!! I've heard they can go strong for a lot of miles and even with stage 2 mods.

Finally got the car to the garage today as it still wasn't running right after I changed some parts, I will update with exactly what was wrong with it but as I suspected it was a vacuum leak. There was a crack to one of the hoses, something to do with what connects the intake or something. He done some tests and the car was running about 20 percent too rich! Put a bit of tape on it to check and they dropped back down to normal so found the fault.

Picking her up tomorrow and hoping she stays ok for more than 2 weeks!  :grin:
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Offline SANDEGTI

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Re: Pretty bad PCV…
« Reply #6 on: August 25, 2022, 08:48:59 pm »
I hate to think how bad a 15 year old primary oil separator looks inside!  An absolute arse to get to though, but those restricted passage ways are like blocked arteries causing high blood pressure, which can result in a bit of blue smoke.

A lot of hard to diagnose air leaks can be caused by the rocker cover itself. See that section with the green line in the drawing?  It's a chamber ultrasonically welded, which can break apart over time causing a vacuum leak.  That's a last resort though as a new rocker cover is about £150+VAT.  Well, it was a few years ago before Brexit, but god knows how much now!

Gotcha, maybe I'll get my mate round and we'll have a look together if it's a pain to get to. Never seen blue smoke yet, only white on a cold start. Ours is 17 years old although I don't think we have quite hit that high mileage figure just yet!! Ideally I'd love to get really comfortable with the car and tackle the more difficult issues. At the end of the day, we plan to keep it for awhile. Nothing else really interests me for the price and the potential. I'm terrible, as soon as I get back from a days work I look at cars. I may even buy some projects if life allows!!  :thinking:
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Offline ROH ECHT

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Re: Pretty bad PCV…
« Reply #7 on: August 26, 2022, 04:58:49 pm »
Thank you for your response,

Finally got the car to the garage today as it still wasn't running right after I changed some parts, I will update with exactly what was wrong with it but as I suspected it was a vacuum leak. There was a crack to one of the hoses, something to do with what connects the intake or something. He done some tests and the car was running about 20 percent too rich! Put a bit of tape on it to check and they dropped back down to normal so found the fault.

Picking her up tomorrow and hoping she stays ok for more than 2 weeks!  :grin:
Fuel trim data is always a good place to go and check. Rough idle, a decrease in fuel mpg, or just to do a general/periodic check. With the leak sealed, it should last at least three weeks now, LOL.
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Offline SANDEGTI

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Re: Pretty bad PCV…
« Reply #8 on: August 26, 2022, 09:58:19 pm »
Well... today I got the car back and everything seemed a little better, the car was definitely idling better and 100% seemed smoother on and off the accelerator.

As I finally thought the car was fixed, I headed back to work and took a slight diversion (road works in Norwich 24/7) and there was a little tunnel. I decided to give it a little blast and I heard a pretty strange noise after I let off. As I came to a standstill I noticed the car sounded like it was full decat, loud as hell and absolutely stunk!

Jacked the car up at a layby, couldn't see any exhaust clamps that could've potentially fallen off and noticed the noise was coming from the front of the car. Took it straight to the garage I always go to and he found that the cat and turbo have completely blown off and disconnected. He said he never saw anything like that before on these cars. I'll update with a picture now!

Anyway, it's given me the excuse to go for a full new exhaust system as I think it was pretty knackered anyway. Looking for a sports cat now. Glad I love the car otherwise it would've been long gone  :doh: :signLOL:

Do you think this could've caused the hissing sounds, lack of power and weird backfires??


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Offline ROH ECHT

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Re: Pretty bad PCV…
« Reply #9 on: August 27, 2022, 04:54:16 pm »
Yeah, it could've caused all of that.
Strange how it appears to be a press fit with no welds.
K04 PLAY...K04 turbo/S3 INJ. & FMIC/FORGE FMTC, TB hose, & WG actuator/GIAC's H.O. K04 & DSG TUNES/AWE DV/NEUSPEED P-FLO,TURBO OUTLET & TB pipe/AUTOTECH hpfp/BSH Eng.&Trans Mounts/H&R ARB's/Whiteline Performance springs & W.A.L.K./ECS stage-3 BBK/BILSTEIN B8's...ZOOM'DIS...GIAC K04 tune-2007 Volkswagen GTI: 12.823 @ 112.050 MPH__Voting for my Dragtimes link: http://www.dragtimes.com/Volkswagen-GTI-Timeslip-25700.html?r=1

Offline SANDEGTI

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Re: Pretty bad PCV…
« Reply #10 on: August 27, 2022, 07:29:27 pm »
That's what I thought, although upon further inspection it's just come off very cleanly. Must be all that vibration from the last 17 years it's been on there!

I do wonder if it's been a bit off for awhile as I always thought it was slightly louder than a normal MK5  :signLOL:
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Offline pudding

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Re: Pretty bad PCV…
« Reply #11 on: September 01, 2022, 01:13:27 pm »
Can't see the pic but if the pre-cat has snapped cleanly off the turbo flange, that's a known issue.  The catalyst casing is wafer thin steel, but VW still wanted nearly £2K for the downpipe when it was available  :stupid:


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