...OIL LEAK AT OIL-FILLER CAP of ALH engine...

MrSafety

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California... Novato... 25 Mi. N. of S.F.
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2002 Jetta TDI/ALH/01M-'80 240D Mercedes/'81 Rabbit "Caddy"/'99 Lexus ES300
I have a problem leak from around the Oil-Fill Cap !
I have changed the cap at least 3 times and the latest one was new!
So I figure that the crankcase pressure is somehow building up too much either:
(a) because we have an engine that has too much "blow-by"… OR
(b) there are 1 or more restrictions in either the "Hockey Puck-Like"
....... filter that sits on the valve cover … OR
(c) a restriction in the "Breather Hose" that runs between the “Puck" and
....... its connection to the "Intake Air Tube" just before it turns down
....... behind the engine on it's way to the turbocharger… OR
(d) there is too little suction (in general or at certain times) from the turbo ....... charger
My Bentley printed manual calls this the Positive Crankcase Ventilation (PCV) system...
but I also see on this FORUM where many call this the "CCV" system which I presume is short for
"CrankCaseVentilation" system!
I have:
(1) verified that the "Hockey-Puck" filter/separator is not restricted...
(2) verified the “Breather Hose” and it’s connection to the “Intake Air Tube”
..... are not restricted…
(3) there is observable suction of air into the “Breather Hose” when the
..... engine throttle is increased
(4) verified the presence of a 2-wire electrical component at the connection
..... of the “Breather Hose” to the “Intake Air Tube”… and that this appears to
..... be a heater as explained in the Bentley Service Manual.
(5) verified that with the Oil-Fill Cap in place, the crankcase is pretty much
..... air tight when I try to blow air in through the hole in the valve cover that
..... the PCV/CCV “Hock-Puck” draws oil mist and vapors.
I am aware of what is known on this FORUM as the “CCV Mod” whereby an alternative
Oil Mist Separator/Filter is installed on the engine as a means to reduce the buildup of oil residue
on the walls of the intake manifold… but our engine has no such system installed.
Today I replaced the “Hockey-Puck” Filter-Separator in a somewhat desperate attempt to solve this mystery!

Q1 – What is the purpose of the “heater” installed at the connection of the “Breather Hose” to the
....... “Intake Air Tube”?
Q2 – In response to (5) above, should there be an air inlet opening to the
...... crankcase somewhere so that more air is Freely drawn through by the
...... turbo charger’s suction on the Intake Air Tube”?
Q3 – Is it possible that somehow there is a partial loss of turbo suction
....... under certain conditions and this results in insufficient suction and thus
....... the pressure builds up in the crankcase?
Q4 - How does one test to see IF excessive "blow-by" is happening...
...... a compression test?
Q5 - Does anyone have a suggestion as to what I look into next?

Any help will be most appreciated!
Sam Ross
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
There is moisture in the blow by gas. The heater keeps it from freezing and blocking flow.

It's not a positive CV system since there is not an inlet to the crank case as on most gas engines that lets filtered air flow through it.

A compression test might be in order.

Is the sealing surface on the valve cover undamaged? Wrong cap?

Any large vacuum leaks? The discharge from the vacuum pump is into the case but there should be no flow from it except a very minor amount when a vacuum device is operating. Even if there were the flow path to the manifold is so big I can't see the crank case pressurizing.
 

MrSafety

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Location
California... Novato... 25 Mi. N. of S.F.
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2002 Jetta TDI/ALH/01M-'80 240D Mercedes/'81 Rabbit "Caddy"/'99 Lexus ES300
There is moisture in the blow by gas.
The heater keeps it from freezing and blocking flow.
It's not a positive CV system since there is not an inlet to the crank case as on most gas engines that lets filtered air flow through it.
A compression test might be in order.
Is the sealing surface on the valve cover undamaged? Wrong cap?
Any large vacuum leaks? The discharge from the vacuum pump is into the case but there should be no flow from it except a very minor amount when a vacuum device is operating. Even if there were the flow path to the manifold is so big I can't see the crank case pressurizing.
Thanks a lot for your response and I'm already on much the same page
as you when it comes to understanding the distinct differences between
the PCV system on a GAS engine and what Diesels have.
I'll check into and try to monitor our TDI's vacuum system.
Q1 - Do you suppose that modifying and making the TDI's CCV system have a small continuous flow of filtered outside air
introduced into the crankcase... might this make the CCV more "dynamic"/self purging and less likely to build up pressure?

[edit]IF I were to do this, then I would definitely look seriously at the "CCV-Mod" ideas I found on this FORUM.
As I understand these "CCV mod" ideas, they are an attempt to reduce the CCV/EGR systems
from causing the "goo" that forms on the inside of the intake manifold!

Also, someone has made a strong case with me to double up on the
flat/round gasket seals used on the underside Oil-Filler Cap.
They gave me the P/N for this $1-to$2 gasket seal... 06A-103-483-D!
I'll install two of these and see IF this easy fix works!?!
Thanks and I'll report back by next week!
The car belongs to my Son!
Sam Ross
 
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Ski in NC

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Joined
Jul 7, 2008
Location
Wilmington, NC USA
TDI
2001 Jetta ALH 5sp stock
Cap should not leak even if blowby flow is high. Something is wrong with cap sealing. Aftermarket cap??

Redneck blowby flow test: with engine running, loosen oil fill cap see if it tries to blow off. It should just "dance" as there are normal pressure pulses in crankcase. But if on loosening it blows out of your hands and hits the hood, you've got a problem. If it just sits there and dances, you have a good engine and a bad sealing cap.
 

KLXD

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Joined
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Location
Lompoc, CA
TDI
'98, '2 Jettas
A bleed wouldn't work. Unlike a gas engine where the PCV outlet is plumbed downstream of the throttle plate, there is virtually no vacuum in the TDI intake system unless the filter badly plugged.
 

MrSafety

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California... Novato... 25 Mi. N. of S.F.
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2002 Jetta TDI/ALH/01M-'80 240D Mercedes/'81 Rabbit "Caddy"/'99 Lexus ES300
Cap should not leak even if blowby flow is high. Something is wrong with cap sealing.
Aftermarket cap??
Redneck blowby flow test: With engine running, loosen oil fill cap see if it tries to blow off.
It should just "dance" as there are normal pressure pulses in crankcase.
But if on loosening it blows out of your hands and hits the hood, you've got a problem.
If it just sits there and dances, you have a good engine and a bad sealing cap.
A bleed wouldn't work.
Unlike a gas engine where the PCV outlet is plumbed downstream of the throttle plate,
there is virtually no vacuum in the TDI intake system unless the filter badly plugged.
Thanks "Ski in NC" & "KLXD",
KLXD - I agree about the vacuum... on these turbo models,
the "boost" also makes sure that any small low-pressure (a vacuum)
would be destroyed by the air being pushed down the throat of the engine by that turbocharger!
Ski in NC - I really like your Redneck blowby flow test!!
On our MB diesels we pinch off the breather air hose running from the valve cover and see
how long it takes for the engine to stalls!
I hope you are not the inventor of the "Redneck Intake Manifold Flame-throwing Cleaner" method...
for I would NOT be so brazen as to get aluminum that hot and then quince it with cold water!
I cooked my on the patio inside a smoker Bar-B-Q and then let it cool off very slowly before I then
pressure washed the interior surfaces with 1,500 psi water-spray!
Regards,
Sam
 

jake8842

Well-known member
Joined
Nov 24, 2007
Location
oswego, ny
TDI
2001 Jetta GLS 5spd
Are you sure the egr valve is not leaking?? I would be willing to bet it is.
Sprays out the vent hole on the front and looks like the oil filler cap is leaking. Repair = replace egr valve
 

Bran Diezel

Veteran Member
Joined
Jul 13, 2009
Location
Bristol, Va
TDI
On my 5th TDi - 2003 ALH 5spd Wagon
i asked a guru at the dealership and he told me to just flip the rubber gasket under the cap over.

i did it and for the most part i'm staying alot cleaner. i think my egr has a smidge of a leak though.
 

MrSafety

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Location
California... Novato... 25 Mi. N. of S.F.
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2002 Jetta TDI/ALH/01M-'80 240D Mercedes/'81 Rabbit "Caddy"/'99 Lexus ES300
Are you sure the egr valve is not leaking??
I would be willing to bet it is.
Sprays out the vent hole on the front and looks like the oil filler cap is leaking. Repair = replace egr valve
i asked a guru at the dealership and he told me to just flip the rubber gasket under the cap over.
I did it and for the most part i'm staying alot cleaner. i think my egr has a smidge of a leak though.
"jake8842" - I will double check this next week when I get my hands on the car...
but I'm inclined to say not so because this last winter I did the intake cleaning and at that time I replaced all gaskets/seals on the EGR!
"Bran Diezel" - I have three times now replaced the oil cap with a different one and the last time was a new OE cap.
I'm going to throw two new flat gaskets on the oil cap... p/n = 06A-103-483-D ...
and see how they fit or if this makes removal of the cap overly difficult!
IF it is too difficult to turn, then I'll look for a sheet neoprene material that just a bit thicker than the OE gaskets and try making my own!
Thanks,
Sam Ross
 

golf.angers

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Apr 16, 2010
Location
quebec
TDI
golf
i have the same problem and i changed the cap at its still doing it i don't know what it is its not leaking from my egr clearly the cap. could it be that my ccv is blocked ?
 

josh8loop

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Joined
Sep 15, 2009
Location
Vero Beach, Fl.
TDI
2002 VW Jetta TDI Manual(performed 01M to 5-speed swap) - 183,000 miles and climbing!
i have the same problem and i changed the cap at its still doing it i don't know what it is its not leaking from my egr clearly the cap. could it be that my ccv is blocked ?


You could check your CCV oil demisting pads like I did in this video:

http://www.youtube.com/watch?v=kEZzSUQONVA


They may or may not be gunked up. Mine were pretty clean, but I've heard guys say theirs were pretty dirty.





..
 

T_D_I_POWER

Top Post Dawg
Joined
Jun 7, 2007
Location
Savannah. GA. USA - Toronto. ON. CANADA
TDI
'04 VW PASSAT GLS TDI '06 Audi A4 q Avant 6-Spd Sport Pkg
Double the no. of gaskets and it should stop oil from leaking/seeping OFC

2 gaskets on OFC


Double gaskets shown slightly protruding the OFC flange. Smear oil on the gasket for easy removal.


Peace of mind
 

MrSafety

Newbie at Heart
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Location
California... Novato... 25 Mi. N. of S.F.
TDI
2002 Jetta TDI/ALH/01M-'80 240D Mercedes/'81 Rabbit "Caddy"/'99 Lexus ES300
It looks like the oil leak is actually from the EGR!?

Are you sure the EGR valve is not leaking??
I would be willing to bet it is.
Sprays out the vent hole on the front and looks like the oil filler cap is leaking. Repair = replace egr valve
"Jake8842" & Others...
I think you are probably correct that the leak is coming from the EGR (or at least from that direction)!
After installing a new "Breather Filter/PUCK" on top of the valve cover,
to my surprise I found there was noticeably less of a sign of the oil leak at/near the Oil-Filler Cap... BUT...
then yesterday I wrapped a medium square of aluminum foil over/around the Oil-Fill Cap...
and this a.m. when I checked the foil for new signs of a leak,
well I found none on the inside and a small, fain oil spot on the outside of the foil...
and so positioned that it came either directly from the "weep-hole" on the front side of the vacuum actuated "engine-kill flapper valve"...
NO... now I think it is from below the main EGR valve's diaphragm... possibly from its butterfly vavle shaft's hole!?

Q1 - IF leaking from one of the front shaft holes, do you think I could:
..... (a) clean out the shaft opening thoroughly,
..... (b) put in a little packing... then
..... (c) fill it with some of that supper metalized epoxy stuff!?
... OR
Q2 Maybe it is blowing out of a leak in the turbo-pressurized air supply tube
at/near where it's rubber flex-coupling that connects to the EGR's flange!??

So I think you are right " Jake8842 " and I'm one step closer to solving this mystery as well as FIXing the problem.
So I guess I'm back to wrapping either more aluminum foil around and squeezing it tightly around these new suspected areas...
or maybe paper towels and use some narrow painter's tape to hold it in place until the oil spot first shows through!?
Tomorrow I'm changing both lower-control-arms and lower ball joints...
and this will give us a chance to examine things closely and IF we do NOT find an obvious leak,
then apply either the foil or paper towels!?
Sam Ross
 
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Keith_J

Veteran Member
Joined
Apr 12, 2007
Location
West
TDI
2000 Jetta MT
You could check your CCV oil demisting pads like I did in this video:

http://www.youtube.com/watch?v=kEZzSUQONVA


They may or may not be gunked up. Mine were pretty clean, but I've heard guys say theirs were pretty dirty.





..
This is the most likely. Mine were solid with gunk, very little flow area for the blow-by. Since the oil fill cap is on the "misty" side, pressure here would mean lots of oil leakage.

It isn't hard to access, only thing is getting that back right bolt out of the valve cover. My valve cover is attached with regular hex bolts (no socket heads) and a 1/4" drive 10mm with universal joint, long extension and ratchet works fine. I also place a small magnet in the socket to retain the bolts.

Once the valve cover is off, follow Josh8loop's video. If your valve cover drips thick, black oil, the pads are probably clogged.

You could try burning them clean but that would be quite smokey. I soaked in kerosene, then strong TSP solution.
 

golf.angers

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Apr 16, 2010
Location
quebec
TDI
golf
like i said i did have the same problem and did realize that it wasn't my cap and was infact my egr valve. i removed the plastic tubing right after the egg valve and found there was some oil inside the plastic tube but none in the egr valve... i don't quite understand where and how oil got there. can someone help ?
 

MrSafety

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California... Novato... 25 Mi. N. of S.F.
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2002 Jetta TDI/ALH/01M-'80 240D Mercedes/'81 Rabbit "Caddy"/'99 Lexus ES300
I have the same problem and I changed the cap and it's still doing it.
I don't know what it is its not leaking from my egr clearly the cap.
Could it be that my ccv is blocked ?
"golf.angers",
I can read what you say and two of us thought for certain our cap was leaking due to excessive crankcase pressure inside the valve cover... but NOT SO!
A Suggestion for others with is this symptom and reading this
Take a 6-to 10 inch square of aluminum foil and crimp it over/around the oil filler cap after you clean things up thoroughly!
Then after a while, you will know for certain IF the cap is leaking for the oil residue will be mainly on the inside!
Take it from one who knows how to eat humble pie!
After performing the above test, I am now working to see (more likely) exactly where on the EGR ours is leaking...
and it appears to be from a hole in the body of the EGR just below the EGR-function's vacuum diaphragm!
To check this out, after a thorough cleaning I wrapped a thin strip of white fabric several times around the EGR covering the hole.
Now I'm watching to see the tell-tale black oil spot...
and IF so, then it's either "J-B Weld" which is a "liquid/steel/epoxy-resin" or replace the EGR!
The EGR's diaphragm still holds vacuum very well so it appears the EGR's shaft the diaphragm pulls/pushes up/down...
this is probably worn and the oil is now leaking out of the two "weep-holes"... front & back !
I will know soon!?
Sam
 
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Keith_J

Veteran Member
Joined
Apr 12, 2007
Location
West
TDI
2000 Jetta MT
"golf.angers",
I can read what you say and two of us thought for certain our cap was leaking due to excessive crankcase pressure inside the valve cover...
but NOT SO!
A Suggestion for others with is this symptom and reading this
Take a 6-to 10 inch square of aluminum foil and crimp it over/around the oil filler cap after you clean things up thoroughly!
Then after a while, you will know for certain IF the cap is leaking for the oil residue will be mainly on the inside!
Take it from one who knows how to eat humble pie!
After performing the above test, I am now working to see (more likely) exactly where on the EGR ours is leaking...
and it appears to be from a hole in the body of the EGR just below the EGR-function's vacuum diaphragm!
To check this out, after a thorough cleaning I wrapped a thin strip of white fabric several times around the EGR covering the hole.
Now I'm watching to see the tell-tale black oil spot...
and IF so, then it's either "J-B Weld" which is a "liquid/steel/epoxy-resin" or replace the EGR!
The EGR's diaphragm still holds vacuum very well so it appears the EGR's shaft the diaphragm pulls/pushes up/down...
this is probably worn and the oil is now leaking out of the two "weep-holes"... front & back !
I will know soon!?
Sam
Those two holes are there to ALLOW atmospheric pressure to actuate the valve. If these are plugged, the only way for the valve to open is for the valve stem to leak from the intake, this isn't good as EGR will be sluggish and you might have problems. Like a DTC or sluggish performance.

If the stem is weeping, it is doing so due to wear in the guide bushing. There is no cure, only replacement. You could install tubes and route them to a collection container as a stopgap measure. I wouldn't recommend routing it back to the crankcase as there could be dirt from the intake air.
 

MrSafety

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Location
California... Novato... 25 Mi. N. of S.F.
TDI
2002 Jetta TDI/ALH/01M-'80 240D Mercedes/'81 Rabbit "Caddy"/'99 Lexus ES300
Those two holes are there to ALLOW atmospheric pressure to actuate the valve.
If these are plugged, the only way for the valve to open is for the valve stem to leak from the intake.
This isn't good as [the] EGR will be sluggish and you might have problems.
Like [throwing] a DTC or sluggish performance.
If the stem is weeping, it is doing so due to wear in the guide bushing.
There is no cure, only replacement.
You could install tubes and route them to a collection container as a stopgap measure.
I wouldn't recommend routing it back to the crankcase as there could be dirt from the intake air.
Keith,
My sincere thanks for reminding me of how this part of the EGR functions!
What you have said makes perfect logical sense for it is NOT the vacuum (just a lower pressure)
that provides the energy to actuate the EGR...
but rather it is the greater atmospheric pressure coming in through these two holes
and pressing up/out against the underside of the vacuum diaphragm plate that is the greater/real force!
Thanks for reminding me of the physical realities of how this actuator functions!,
Sam Ross
 
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KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
If you plug the vent hole, I don't think the result will be sluggish EGR function. The fact that oil is leaking from it shows manifold pressure is already available.

If you plug it the manifold pressure will open the EGR valve.
 

MrSafety

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Jun 27, 2010
Location
California... Novato... 25 Mi. N. of S.F.
TDI
2002 Jetta TDI/ALH/01M-'80 240D Mercedes/'81 Rabbit "Caddy"/'99 Lexus ES300
... My thoughts are getting somewhat "Rube"!

If you plug the vent hole, I don't think the result will be sluggish EGR function.
The fact that oil is leaking from it shows manifold pressure is already available.
If you plug it the manifold pressure will open the EGR valve.
Thanks "KLXD" for joining in on this discussion.
Actually early this a.m. I was pondering further just how I might salvage more use out of this EGR…
that I'm all but certain is the original production part.
I have been thinking that instead of plugging these two holes
(that I now think should be called "atmospheric vent"(inlet) holes)
and run these lines uphill and to the side where they would eventually join together and
pass through a small (increased volume) chamber like those used by Mercedes to dampen/retard vacuum systems.
However in this case the chamber would act to separate oil droplets from the vapor/gases...
and IF this chamber is also elevated above the EGR, then when the engine is shut down,
oil in the chamber would drain back into/below the EGR's diaphragm and
possibly even back into the intake air tube where the oil came from…
and join with all the other oil droplets that are normally there on their way
to be cooked onto the walls of the intake manifold where I can clean/remove them again at some future date!
Yes, I'm purposely being just a little facetious here but I’m serious about whether this might just work
as a way extend the useful life of the EGR that cost’s ~$180?
[edit]... But can I put together such a batch of Rube plumbing
without dampening the EGR's proper functioning!?

Sam
 
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Keith_J

Veteran Member
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Apr 12, 2007
Location
West
TDI
2000 Jetta MT
Yes, you could tap those holes, then thread small tube fittings allowing a venting system that would control weeping.

Plugging the holes would indeed make EGR sluggish which might throw a DTC but also cause drivability issues. Consider if there is a good bit of EGR and you need a lot of power, the EGR wouldn't close fast enough because the air trapped in the EGR diaphragm cavity would also be at manifold pressure, above atmospheric pressure. And with a call for more power, manifold pressure would be increasing.
 

MrSafety

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California... Novato... 25 Mi. N. of S.F.
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2002 Jetta TDI/ALH/01M-'80 240D Mercedes/'81 Rabbit "Caddy"/'99 Lexus ES300
"Keith_J",
Your words from above remain below in black, and mine will be in this Bright Blue!

You could tap those holes, then thread small tube fittings allowing a venting system that would control weeping.
And I might even try this just to prove to myself (and others who really want to save that ~$180 for a new EGR)...
but I'm also planing for my backup which is to eventually replace this leaky EGR!

Plugging the holes would indeed make [the] EGR sluggish which might throw a DTC but also cause drivability issues.
Consider if there is a good bit of EGR and you need a lot of power,
the EGR wouldn't close fast enough because the air trapped in the EGR diaphragm cavity would also be at manifold pressure, [which is] above atmospheric pressure.
And with a call for more power, manifold pressure would be increasing.
And it is exactly such performance issues that I have pondered about that make me plan to eventually replace the EGR!
I have found a German made "Wahler" brand that would be ~$195+our sky-high 9+% Calif. sales tax rate!
Regards - Sam Ross
 
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josh8loop

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Sep 15, 2009
Location
Vero Beach, Fl.
TDI
2002 VW Jetta TDI Manual(performed 01M to 5-speed swap) - 183,000 miles and climbing!
Yes, you could tap those holes, then thread small tube fittings allowing a venting system that would control weeping.

I had thought of this Idea recently myself. It would be a temporary bandaid fix, but certainly better than shelling out $180.00 immediately, and better than having oil residue contaminate belt etc. Also, if one was concerned that the air/oil/carbon material would build up under the actuator diaphragm limiting and slowing down travel they could just periodically remove the bleed fitting there and use a cleaner that would flush it out. I enjoy this "out of the box" type thinking! It's refreshing :D






..




..
 

Keith_J

Veteran Member
Joined
Apr 12, 2007
Location
West
TDI
2000 Jetta MT
Don't over-think the solution, just plumb the EGR vent to the CCV inlet to the corrugated hose from the air box to turbo inlet. I'm surprised mine has never weeped a single drop. Probably because I tapped mine with 1/8 NPT for the boost gauge, only to not plan carefully and drilled the hole in the wrong place. I fixed it with JB Weld and haven't had a single issue but it always haunts me.

IMHO, wear in the bushing which lets it weep is from misalignment or distortion. Either abrasive dirt or thermal distortion (EGR cooler sluggish?). Or both?
 

Deadend

Veteran Member
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Aug 17, 2009
Location
Calgary
TDI
2001 Jetta
Just thought I'd mention, today I replaced my oil filler cap, just for good measure before taking any steps to alleviate EGR weepage.

And I noticed that the old oil filler didn't have a rubber gasket on it.... at all......

Don't know how that slipped by me at all, and not to knock this thread off the good discussion of ccv de-misting, but just a quick heads up to a bit of Occams Razor.

Incidentally I also ordered a couple spare oil filler gaskets... and they sent me like 7 of them. So if any one wants on, PM me.
 
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