What's involved in changing out the Valve stem seals?

NYTDIBoy

Veteran Member
Joined
Nov 20, 2003
Location
Rhinebeck, NY
TDI
2000 Jetta GLS; 2013 Passat SE 6SP
Hi,

Been battling a soot issue with my car since I owned it and I think I am down to only 1 or 2 major culprits. The major one is the valve stem seals. I think they are bad because I have observed an awfully high pressure (and volume) of air comming out of the CCV.

So has anyone done this job? If so, how bad is it? I assume it involved everything in a TB job, plus removing the cam?
 

Mad_Dasher

Veteran Member
Joined
Jan 10, 2005
Location
Indianapolis
TDI
2002 silver Jetta
When valve stems seals go bad the usual problem is excessive oil consumption. But on a diesel engine with a turbo there is a positive pressure in the intake manifold instead of the vacuum that exists in a gas engine. Thus a diesel engine does not develop the vacuum to suck oil down the valve stem into the intake manifold. Nobody replaces valve stem seals in a diesel - even diesels without a turbo.

How many miles are on your jetta? How much oil are you consuming?
 

whitedog

Veteran Member
Joined
Jul 12, 2004
Location
Bend, Oregon
TDI
2004 Jetta that I fill by myself
Mad_Dasher said:
Nobody replaces valve stem seals in a diesel - even diesels without a turbo.
Please be more accurate. The guy that rebuilds our heads at work always replaces the stem seals.

That's just one guy, but I bet if you asked frank06, he will tell you that he always replaces stem seals.

That's two guys, but if you ask anyone that has replaced valve guides in an ALH head, you will find that they too replace the stem seals.

To say "Nobody replaces valve stem seals in a diesel" is just plain wrong.
 

sdeck

Veteran Member
Joined
Aug 25, 2006
Location
Northern Colorado Front Range
TDI
2003 Jetta, 253K, 01M, DLC520s, VNT-17(sold); 2014 Passat SE 6M, 61,000 miles (Feb 16 buyback date)
I have the same question, as I am using about 1 quart every 2000-3000 miles. Compression is 490/490/490/490. ('03 Jetta). Haven't done a leak-down. What else should I be checking if it is not the valve seals? Not seeing much smoke outside of normal puff when I step on it. Car seems loud to me (sounds like a diesel), especially at start up. Acceleration is OK, (auto).

I was reading about this in my Bentley's manual this morning. It indicated that leaking valve stem seals is a major source of excessive oil consumption in the TDI. It indicated it occurs during decelleration with smoke evident when you let up on the go-pedal
 
Last edited:

rjr311

Veteran Member
Joined
Jan 14, 2006
Location
Western Shawnee, Kansas
TDI
2004 Passat Wagon , 1996 Passat sedan
If you are suffering leaky valve seals it is probably time to check the rest of the cylinder head components.

I replace valves ( or at least re-face), valve guides and valve seals when head is removed.
The time and money is but a pittance _now_ compared to doing it a year or two later and having to do the timing belt job and replacing the head gasket as well a second time.
And while you are at it have a multi angle valve job done ( 3-way)

Here is a "dummies guide to valve work" -
http://home.hiwaay.net/~langford/corvair/valvejob.html

A similar analogy would be changing oil but not replacing oil filter.

Robert

whitedog said:
Please be more accurate. The guy that rebuilds our heads at work always replaces the stem seals.

That's just one guy, but I bet if you asked frank06, he will tell you that he always replaces stem seals.

That's two guys, but if you ask anyone that has replaced valve guides in an ALH head, you will find that they too replace the stem seals.

To say "Nobody replaces valve stem seals in a diesel" is just plain wrong.
 
Last edited:

PDJetta

Top Post Dawg
Joined
Nov 6, 2003
Location
Northern Virginia
TDI
'04 Jetta GLS TDI Pumpe Duce Platinum Grey w/ Leather
The "High" blow by (crank case pressure) is not related to bad valve stem seals. "High" is subjective. It may be normal. Diesels, due to high combustion pressures, have more blowby and may seem high to most people.

The only reason to consider replacing valve guide seals is because of high oil use, and in a diesel, valve guide seals do not control oil as much as in a gas engine, since there is no intake manifold vacuum to suck more oil past the seals than would flow from gravity (like in a gas engine).

If your engine does suffer from excess blowby, it is probally from worn piston rings/cylinder bores. Oil consumption should be high as well.

--Nate
 

PDJetta

Top Post Dawg
Joined
Nov 6, 2003
Location
Northern Virginia
TDI
'04 Jetta GLS TDI Pumpe Duce Platinum Grey w/ Leather
sdeck said:
I have the same question, as I am using about 1 quart every 2000-3000 miles. Compression is 490/490/490/490. ('03 Jetta). Haven't done a leak-down. What else should I be checking if it is not the valve seals? Not seeing much smoke outside of normal puff when I step on it. Car seems loud to me (sounds like a diesel), especially at start up. Acceleration is OK, (auto).

I was reading about this in my Bentley's manual this morning. It indicated that leaking valve stem seals is a major source of excessive oil consumption in the TDI. It indicated it occurs during decelleration with smoke evident when you let up on the go-pedal
"It indicated it occurs during decelleration with smoke evident when you let up on the go-pedal"

That applies to gasoline engines. When the throttle closes in a gas engine (when you take your foot off of the gas) on engine over run, a large manifold vacuum develops and this sucks oil past worn valve guides and bad VG seals.

Also, I would imagine a pluged/kinked turbo oil return line or worn turbo bearings/seals could increase consumption, as well as oil leaks.

You can replace the valve guide seals with the head on the car. Cam comes off and lifters come out. Each cylinder is done at TDC and the valve keepers released, springs are removed and the seals replaced. On the diesel, the valve will rest right on the piston top. On a gas car, compressed air (or a nylon rope inserted into the cylinder thru the spark plug hole) keeps the valve from falling into the cylinder. You do need several special tools to do this, though.

--Nate
 
Last edited:

Mad_Dasher

Veteran Member
Joined
Jan 10, 2005
Location
Indianapolis
TDI
2002 silver Jetta
Whitedog,

I agree if your rebuilding the head, of course you would replace the seals. I was answering in the context of the question posed in the post. I wasted time one afternoon replacing the valve stem seals on my dasher. It was of no help in slowing oil consumption. No throttle plate means little of no intake vacuum. Thus the seals are rarely a problem on a diesel. But I would, however, insist they be replaced on a rebuilt head.
 

whitedog

Veteran Member
Joined
Jul 12, 2004
Location
Bend, Oregon
TDI
2004 Jetta that I fill by myself
Thanks. That's why I think that clarity is important; it makes for less confusion.
 

Franko6

Vendor , w/Business number
Joined
May 7, 2005
Location
Sw Missouri
TDI
Jetta, 99, Silver`
I appreciate it when I am mentioned by name as someone who 'knows'... thanks, whitedog...

Here is the thing that most people seem to misunderstand about a turbo'd engine. There is no oil sucked into the engine from valves. There is constant pressure that goes through the intake and exhaust valves into the crankcase. That means BLOW-BY. That can cause a lot of oil consupmtion by pushing oil into the intake manifold by way of the crankcase vent (CCV).

I just took apart a head that I know must have been having a lot of oil consumption simply because the CCV would not be able to handle all the crankcase pressure pushing oil into the intake manifold and therefore, causing excessive oil usage by burning the crankcase oil. It was simply the excessive clearance between the valve stem and the valve guide that caused this issue.

If you have valve guides that are so worn that there is a substantial amount of blow-by, I am not so certain that valve guide seals are going to cure your problem. I think that the pressure from the crankcae venting is going to overcome the springs holding the valve seals in place.

Although I do always replace the valve guide seals when rebuilding a cylinder head, I think to do seals without considering the valve guide is to do things in half-steps. The valve guide has more to do with blow-by than does the valve seal. As a matter of fact, I think that the valve seal is superfulous. Even though I always install them, I think they are of little consequence.

I think that a close tolerance between valve stem and valve guide and a very accurate and concentric cutting of valve sealing surfaces would drastically reduce oil consumption and leads to long valve and valve guide life.

I am also a very strong believer in the aftermarket Crank Case Vents that are available. The small CCV atop the valve cover is simply not large enough to handle the demands of the engine, especially an engine that has been modified for additional horsepower.

A agree that valve stem seals can be replaced without removing the head, but doing seals without taking care of the underlying cause is futile.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
I agree. Putting new valve stem seals on worn out valves mounted in worn out guides won't do a thing.

It is possible there is some oil ring soot built up, and there is only one method I know of short of an overhaul that can help with that.

BG makes a "compression restorer" that introduces and EXTREMELY powerful substance into the engine oil, and if used properly can loosen and remove the crap built up in the rings. I am not a big advocate of additives, but the BG stuff actually does work.

Also, there may be some oil blowing past the turbo seals, although usually that goes pretty quick when it happens.
 

PDJetta

Top Post Dawg
Joined
Nov 6, 2003
Location
Northern Virginia
TDI
'04 Jetta GLS TDI Pumpe Duce Platinum Grey w/ Leather
NYTDIBoy said:
Hi,

Been battling a soot issue with my car since I owned it and I think I am down to only 1 or 2 major culprits. The major one is the valve stem seals. I think they are bad because I have observed an awfully high pressure (and volume) of air comming out of the CCV.

So has anyone done this job? If so, how bad is it? I assume it involved everything in a TB job, plus removing the cam?
"Soot" is an indication of overfueling or not enough air, or retarded timing. Turbo problems, mis adjusted injection timing, and worn injectors can cause black smoke. Oh, plugged air filters (or snow screen) can cause it too.

--Nate
 

greengeeker

Vendor
Joined
Feb 8, 2006
Location
Cambridge, MN
TDI
2002 Jetta GLS
If blue smoke on startup is the case and you go ahead and replace only the stem seals, are you going to have to redo the job later because the worn guides weren't replaced? To rephrase, can your seals go bad and still have good valve guides?
 

whitedog

Veteran Member
Joined
Jul 12, 2004
Location
Bend, Oregon
TDI
2004 Jetta that I fill by myself
Frank, I was thinking the same thing on valve guides. Saw a Cat 3304 that had two guides so worn, the end of the valve had probably 3/32 inch play. Exhaust soot was in big gobs around the valves.

Of course the block with holes on each side was what finally made them shut it down.
 

NYTDIBoy

Veteran Member
Joined
Nov 20, 2003
Location
Rhinebeck, NY
TDI
2000 Jetta GLS; 2013 Passat SE 6SP
PDJetta said:
"Soot" is an indication of overfueling or not enough air, or retarded timing. Turbo problems, mis adjusted injection timing, and worn injectors can cause black smoke. Oh, plugged air filters (or snow screen) can cause it too.

--Nate
I figured Overfueling or not enough air. The car has been chipped, but even before it sooted pretty bad. I do the timing belts myself, have all the correct tools and check the timing advance with my VAGCOM, everything appears to be fine. The car get's 47-49 mpg consistantly in mixed highway/city driving. Oil consumption is minimal (about 1 quart every 10,000 miles), and I don't seem to have any power problems. The car now has 170k on the clock. I know nothing about the first owner or how it was maintained. Got it with a bit less than 60k on the clock and when I did the first TB I pulled and cleaned the intake because it was pretty clogged and had the MAF changed under warranty. I also pulled the snowscreen out soon after getting the car so it's not clogged. I keep a good eye on the filters and change the air filter every oil change (sometimes every other if it looks clean enough).

The only time the car soots real bad is under moderate to high acceleration. It is not nearly as noticable in the higher gears as it is in the lower gears. The reason I ruled out overfueling is the cars consistant and high mileage. When I saw what seemed to me to be real high CCV pressure I thought it might be pressure from the intake leaking out past the valve stem seals. That's what led me down the not enough air path. other items on the not enough air path would be sticky VNT vanes ("actual" boost levels vs "requested" boost in VAG-COM seems to track nice in the high gears) or maybe a badly clogged intake again. I'm hoping neither of those is the case though as the power doesn't seem to be lacking and VAG-COM readings all appear normal.

How about an exhaust problem? The car has the original full exhaust on it. What would a clogged or failing cat do?

The other choice is the worn injectors. I seriously thought about ordering a set of injector tips from TDiParts with my order the other day, but didn't. My reasoning against the injectors was the high mileage. I thought if the injectors were dirty that the mileage would be poor, but I have been known to be wrong before!

Thanks for all your help with this problem that has been bugging me since I bought the car!
 

Franko6

Vendor , w/Business number
Joined
May 7, 2005
Location
Sw Missouri
TDI
Jetta, 99, Silver`
Ok, a simple test for blowby... pull the CCV off. Loosen the oil cap. If it flys off the hole, you've got too much blowby... hehe..

I've actually seen an engine with so much blowby that he couldn't shut it off. Getting oil in the car was a horrible mess 1/2 went in the hole, the other half just blew everywhere. He lost a set of rings in TX and milked it home about 500 miles.

Let's just say we've got it narrowed down. It's probably not your injectors... It's running way too good. It's not timing. or the same answer. It's probably got great compression, but you can check that easily enough. And assuming that is ok, then you've only got one thing left... really worn exhaust guides (probably intake too).

To be very blunt about the valve guide seals, they aren't going to hold back exhaust gasses blowing through a loose valve guide. There is only one way to fix the guides... remove the head.

If you are getting 49 mpg, I can't imagine what a fixed head will do...

You also might check VAG-COM block 11 and see that the VNT is moving freely. Go to the basic settings and that will cycle your VNT.

The other thing about 'soot'... if you are burning a qt of oil in 10,000, that's not a lot, but it seems that your smoking may be due to a small amount of oil. It does combust in the engine, but at the wrong time and without much good effect. That may be what you are seeing under hard acceleration.
 
Last edited:

breadman 50

New member
Joined
Apr 28, 2015
Location
Elmira, NY
TDI
2002 Jetta TDI
Timing Belt broken at 30,000 on my 2002 Jetta

Last week the timing belt broke on my 2002 Jetta TDI. The car had 161,000 on it and I thought it was going strong. I thought it would be the last car I owned. I had had other diesel Rabbits, Golfs and Jettas. I take very good care of my cars. I had changed the oil at all the recommended times, etc. My last Jettas went over 250,000 but rusted out. They were a 1985 and 1986.

I was going up a slight hill in 3rd gear and all of a sudden the engine locked up. Fortunately I was near a home. I called our mechanic to see what he thought. He asked me to try to start the car again as he believed he knew what it was. The lower engine was trying to start but to no avail.

I had the car towed to the garage. The engine head was disassembled and it looked like there was damage done to the valve stems as they were bent.

My question is , does anyone think that it is good to try to order a new full cylinder head or a full engine? I found one online that matched the ALH engine code. They are asking $3250 for it.

I have been advised by several people not to waste the money in fixing it up. My problem is is that this car is in very good condition otherwise. It never lost a drop of oil between oil changes which a 1998 TDI Jetta I had did do that.

This car has the heated seats, sunroof and a CD player cassette. Tires that are in very good shape, plus snow tires not on rims in very good shape. The car handled so well and it didn't have any rust except for a little starting on the edge of the front hood, which could be easily fixed.So you can see why I'm torn between these two options.

I have test driven a couple of TDI's in our area. One is a 2013 with only 25,000 mi. on it. They want $17,000. Another one is a 2009 TDI that has 51,000 mi on it and they want $14,500. So it boils down to the question if anybody would fix up a 2002 if they had one???

Thanks for your help.
 

maxmoo

Veteran Member
Joined
Jan 19, 2011
Location
Lakefield, Ontario, Canada
TDI
2000 golf, 2001 golf, 2000 beetle, 2003 wagon, 2004 golf, 2004 jetta, all diesels
Last week the timing belt broke on my 2002 Jetta TDI. The car had 161,000 on it and I thought it was going strong. I thought it would be the last car I owned. I had had other diesel Rabbits, Golfs and Jettas. I take very good care of my cars. I had changed the oil at all the recommended times, etc. My last Jettas went over 250,000 but rusted out. They were a 1985 and 1986.

I was going up a slight hill in 3rd gear and all of a sudden the engine locked up. Fortunately I was near a home. I called our mechanic to see what he thought. He asked me to try to start the car again as he believed he knew what it was. The lower engine was trying to start but to no avail.

I had the car towed to the garage. The engine head was disassembled and it looked like there was damage done to the valve stems as they were bent.

My question is , does anyone think that it is good to try to order a new full cylinder head or a full engine? I found one online that matched the ALH engine code. They are asking $3250 for it.

I have been advised by several people not to waste the money in fixing it up. My problem is is that this car is in very good condition otherwise. It never lost a drop of oil between oil changes which a 1998 TDI Jetta I had did do that.

This car has the heated seats, sunroof and a CD player cassette. Tires that are in very good shape, plus snow tires not on rims in very good shape. The car handled so well and it didn't have any rust except for a little starting on the edge of the front hood, which could be easily fixed.So you can see why I'm torn between these two options.

I have test driven a couple of TDI's in our area. One is a 2013 with only 25,000 mi. on it. They want $17,000. Another one is a 2009 TDI that has 51,000 mi on it and they want $14,500. So it boils down to the question if anybody would fix up a 2002 if they had one???

Thanks for your help.
....It sounds like you already know the answer. :)
 

csstevej

Top Post Dawg
Joined
Aug 12, 2004
Location
north nj
TDI
2001 golf tdi 4 door auto now a manual, mine, 2000 golf 2 door M/T son's,daughters 98 NB non-TDI 2.0, 2003 TDI NB for next daughter, head repaired and on road,gluten for punishment got another tdi 2001NB,another yellow tdi NB
As Whitedog stated above.......in a heartbeat. I would get ahold of franko6 about an exchanged head with a new complete TB kit with all the parts associated with a head change and motor on.......it will be far less cheaper in the long run.

I picked up an 03 nb that was in an accident, popped air bags and some plastic damage on front end nothing major, body and inside in nice condition.....not too bad but had a botched TB job with 212,xxx miles on it.........it's now my youngest daughter's car.
 
Last edited:

FixItDaily

Active member
Joined
Nov 11, 2018
Location
Washington
TDI
2003 Golf
I found this thread looking at how to fix potentially leaky valve guides and seals. I bought an 03’ Golf TDI. Since owning it I’ve upgraded the turbo and installed a performance head from Kerma with a stage two cam (head was ported). The head came assembled and looked pretty nice, but since installing it I get smoke on startup when the car sits for a while, especially if it’s cold. I’ve yet to get out a borescope to check the tops of the pistons to see if oil may be leaking down onto the tops. The turbo was new, so I can’t imagine that it’s leaking oil. But before switching it I never added oil to the car. It’s not a lot, maybe just over 1/2 a quart in 3000 miles. I use 5w40 synthetic oil. My other thought was blow by caused by the extra airflow so I upgraded to the larger billet CCV from Kerma (looks nice, seems to flow much better). Engine has 58,000 miles on its last rebuild. I get 40+ mpg with the bigger injectors and higher boost. Car does not blow blue smoke when driving or during hard acceleration. EGR is deleted, and the car is tuned. I am in Washington State, good techs are hard to come by so I’ve done most of the work myself and with a little help from people with more experience than I have. A VW dealership has been involved on occasion. Should I try a heavier oil? Should I add more ventilation to the valve cover? Thanks!
 

Invig

Well-known member
Joined
Aug 15, 2021
Location
Adelaide
TDI
Mk5 Jetta BKD
Ok, a simple test for blowby... pull the CCV off. Loosen the oil cap. If it flys off the hole, you've got too much blowby... hehe..

I've actually seen an engine with so much blowby that he couldn't shut it off. Getting oil in the car was a horrible mess 1/2 went in the hole, the other half just blew everywhere. He lost a set of rings in TX and milked it home about 500 miles.
Hey Frank06

How would you rate this blowby? Its running well fuel wise, and doesn't blow any smoke.


If its bad enough, I wonder if you post heads to Australia, and if its worth it?? I don't drive much more than 3000km/year.

Can I just put up with it without destroying the engine?

Cheers,
Ben
 
Top