fouled plugs diagnosis? 2002 VW Beetle 2.0

[zanzabar]

plugs are left-right cyl 1-4 (left closest to timing belt, passenger side).



Cyl #4 plug is almost completely covered in gunk, the pic was taken after I tried to clean it off. That stuff is hard and baked on. This car has some significant and increasing oil consumption. It has been getting worse over recent 6 months, up to about 1qt/1500 miles now. Car has 102,000 miles total. These plugs have just under 30k on them.

What's going on? Sticky rings leading to too much oil blowby? Head gasket leak? Why the gradient in fouling from cyl 4 -> 1?

 

[mattd]

Sounds like the oil control rings on those 2 cylinders are tired. VW uses low tension oil rings on this engine. If the car is not driven hard regularly, it will develop oil consumption problems. Best fix is to remove the rods and hone cylinders with new rings.

 

[zanzabar]

I was afraid that would be the answer. What would be the 2nd best fix?

Soak cylinders overnight in solvent? AutoRx? Italian tuneup?

Any chance this is result of something simple like valve cover gasket, or crankcase breather?

 

[Quest]

I suggest establishing a baseline first by means of performing wet/dry compression test on all 4 cylinders before you try something.

Q.

 

[shDK]

It.s a well known problem on that engine. You can try give it som engine cleaner in the engineoil. If that doesent help. Try hone the cyllinder and change the piston rings.

 

[mattd]

Originally Posted By: zanzabar
I was afraid that would be the answer. What would be the 2nd best fix?

Soak cylinders overnight in solvent? AutoRx? Italian tuneup?

Any chance this is result of something simple like valve cover gasket, or crankcase breather?


Unlikely. You can try a soak but more than likely will not fix it. As someone else said it is a well known issue on this engine.

Best chance is someone to go out and beat the [censored] out of it. Is this car a manual?

 

[JAG]

If that 2.0 liter engine is similar to the 1.8T's intake manifold and PCV line routing to the driver's side of the intake manifold, then that PCV line's oil vapors are getting most drawn into the cylinders on the driver's side. I put a little catch can on that PCV line in my 1.8T and it collects a fair amount of oil/water. You could have an engine problem going on as well and if there is a ring problem, blowby will increase, further fouling your plugs from the extra oil going through the PCV system.

 

[clarkflower]

Originally Posted By: zanzabar
plugs are left-right cyl 1-4 (left closest to timing belt, passenger side).



Cyl #4 plug is almost completely covered in gunk, the pic was taken after I tried to clean it off. That stuff is hard and baked on. This car has some significant and increasing oil consumption. It has been getting worse over recent 6 months, up to about 1qt/1500 miles now. Car has 102,000 miles total. These plugs have just under 30k on them.

What's going on? Sticky rings leading to too much oil blowby? Head gasket leak? Why the gradient in fouling from cyl 4 -> 1?


You stole my plugs...

Actually I have one bad just like it.
I was told valve guides

I tried MMO 10 hours running in the crank.
A few months later Seafoam in the crank for 20 hours

Got nothing from them

 

[TomYoung]

Before pulling this engine apart, I would:

1. Change the oil to one of those known for cleaning function (PP, Ultra, PYB, GTX) in VW recommended grade,
2. Add a full can of Seafoam to crankcase.
3. Drive 1,000 miles (why not?, you are in partial rebuild territory anyway) Change oil.
4. Then check compression.

You are looking for your problem to be gummed/sticky piston ring. That could be the case.

My bet would be leaky valve guides.

This engine gets smack-talked all over the place, but is actually a very reliable and durable piece.

Also, let's lose the triple electrode plugs and replace with OEM, or NGK, Bosch etc.

If it is any consolation, I have seen far worse plugs on engines that run well and are not burning that much oil.

Also, your oil consumption is completely acceptable.

 

[morris]

upper lube for a fix? i agree with Tom Young. dont take the engine apart till you try a fix of some kind, will not cost much

 

[antiqueshell]

Originally Posted By: TomYoung


Also, let's lose the triple electrode plugs and replace with OEM, or NGK, Bosch etc.


Although these triple tips were not spec'd in US AEG engines, they were in cars sold elsewhere with the identical engine.

Should be no issue with them.

 

[zanzabar]

Many suggestions online to use those triple electrode NGKs. I replaced the plugs with Autolite double platinums (they didn't have the NGKs at AZ). Told the owner to bring the car back in 1000 miles so I can pull the plugs to inspect.

 

[UG_Passat]

Originally Posted By: TomYoung


Also, let's lose the triple electrode plugs and replace with OEM, or NGK, Bosch etc.


THose are NGK's

It says it on the insulator

 

[zanzabar]

Might this be one of those AEG engines with rings installed upside down? Why is it worst on cyl#4? Maybe PCV issues? Going to get another look at it next week and see what the new plugs look like.