Baffled,,,Any guru's wanna take a crack?

[Pseudotropheus]

As I do "Engines" this quarter in school. I decided to bring the Beetle in the shop and run a ton of tests.
I am going through about 1 qt of oil every 400-500 miles.

Yet, its not shooting out the tail end. I dont have a leak or any signs of dripping. I ran a compression test on all cylinders. Getting about 105-110 PSI on 1 crank, and as high as 190-200 PSI on 4 cranks.

I decided to do a Cylinder leakage test. I am running about 25%to 31%. There is supposed to be about 20% leakage. So its a little higher, however, it is no where near the danger zone.

With the slightly higher readings I was thinking Piston Rings. However, I would venture to guess that these readings, should not be a cause for concern.

I did run a Bore scope on all cylinders, and noticed a very excessive amount of "carbon" build up on the walls and atop of the pistons. I am gonna run some B&G 44K on it with some "Supreme-o" gasoline. See if this burns it away.

Still, how can I be chewing up this much oil. This baffles me... I cannot figure out where it is going...

[savethebluths.org]

Originally Posted by Pseudotropheus

As I do "Engines" this quarter in school. I decided to bring the Beetle in the shop and run a ton of tests.
I am going through about 1 qt of oil every 400-500 miles.

Yet, its not shooting out the tail end. I dont have a leak or any signs of dripping. I ran a compression test on all cylinders. Getting about 105-110 PSI on 1 crank, and as high as 190-200 PSI on 4 cranks.

I decided to do a Cylinder leakage test. I am running about 25%to 31%. There is supposed to be about 20% leakage. So its a little higher, however, it is no where near the danger zone.

With the slightly higher readings I was thinking Piston Rings. However, I would venture to guess that these readings, should not be a cause for concern.

I did run a Bore scope on all cylinders, and noticed a very excessive amount of "carbon" build up on the walls and atop of the pistons. I am gonna run some B&G 44K on it with some "Supreme-o" gasoline. See if this burns it away.

Still, how can I be chewing up this much oil. This baffles me... I cannot figure out where it is going...

Ide have to start off by saying beetles eat a higher amount of oil than most cars so im not too worried but we'll start there.

What I think you have is a hose leak, reason why its "invisible" is it only leaks when the pressure builds up when you're driving and falls to the ground your speeding away from. Check the oil coolant line's to start, then check the oil coolant seal that's on top of the oil filter then do what I do by looking for the "goop"

If you jack the car up, look where any oil might be running on the underside, mind you you aren't losing a whole lot so its not going to be terribly obvious. Check the oil filter, if its goopy on the end your coolant seal is bad, if you have an area under the axle that the oil might be pooling then you should find it.


Keep us updated.

[Pseudotropheus]

With the excessive carbon build up on the piston and such. Wouldnt this be a good indicator of worn valve guide seals?

If they were worn, wouldnt the oil just kind of stay there until the motor warms up and the seals expand?

I mean the only smoke I shoot is on cold mornings, from the condensation. This goes away after about 2-3 minutes down the road.

Also, could worn spark plugs cause the excessive build up from not burning the fuel correctly?

[Smileybug]

I know that on some of the early 2.0's there were issues with I think piston rings installed upside down. Its a problem across the VW models.

[vdubbugman53]

Originally Posted by Smileybug

I know that on some of the early 2.0's there were issues with I think piston rings installed upside down. Its a problem across the VW models.

yes many of the AEG motors came with oil scrapers that were installed upside down

[savethebluths.org]

Originally Posted by Pseudotropheus

With the excessive carbon build up on the piston and such. Wouldnt this be a good indicator of worn valve guide seals?

If they were worn, wouldnt the oil just kind of stay there until the motor warms up and the seals expand?

I mean the only smoke I shoot is on cold mornings, from the condensation. This goes away after about 2-3 minutes down the road.

Also, could worn spark plugs cause the excessive build up from not burning the fuel correctly?

yes yes and yes but I believe its a really really common thing to have gunked up piston heads.

[akasha1963]

"mind you you aren't losing a whole lot so its not going to be terribly obvious"

That is a huge amount of oil to be dropping in 400-500 miles. The underside of the car should be coated if it is leaking under pressure. If it was burning you would see black around the tail pipe & bumper. And you arent seeing any drip under the car when it's parked? It IS a mystery.

[Pseudotropheus]

There is no leaks or signs of leakage. Took an airhose and cleaned off the motor as best as I could yesterday. Still, no signs of leaks. No smoke. Im gonna look at a few things, that people have suggested, and see what I find.

Im gonna run an oil pressure test today and see what results I get. I dont suspect any thing wrong with oil pressure, however, im going to run the test anyways.

[Pseudotropheus]

Originally Posted by savethebluths.org

Ide have to start off by saying beetles eat a higher amount of oil than most cars so im not too worried but we'll start there.

What I think you have is a hose leak, reason why its "invisible" is it only leaks when the pressure builds up when you're driving and falls to the ground your speeding away from. Check the oil coolant line's to start, then check the oil coolant seal that's on top of the oil filter then do what I do by looking for the "goop"

If you jack the car up, look where any oil might be running on the underside, mind you you aren't losing a whole lot so its not going to be terribly obvious. Check the oil filter, if its goopy on the end your coolant seal is bad, if you have an area under the axle that the oil might be pooling then you should find it.


Keep us updated.

Its due for new oil and filter anyways, i'll take a look at it, and see what I can find.

[2005Beetle]

I'll bet your problem fixes itself with this oil change. I'm thinking someone put a wrong weight in last time and that's the cause of your disappearing oil. I had the same thing with power steering when I accidentally put the wrong fluid in.

BTW: My local VW dealership sent me a reminder to bring the bug in for an 80k-mile service. Should I bother or can I handle it myself?

[Canadianbugin]

Originally Posted by 2005Beetle

I'll bet your problem fixes itself with this oil change. I'm thinking someone put a wrong weight in last time and that's the cause of your disappearing oil. I had the same thing with power steering when I accidentally put the wrong fluid in.

BTW: My local VW dealership sent me a reminder to bring the bug in for an 80k-mile service. Should I bother or can I handle it myself?

Time for TB & WP and thermostat.And acc belt and tensioners...

[Canadianbugin]

Originally Posted by Pseudotropheus

As I do "Engines" this quarter in school. I decided to bring the Beetle in the shop and run a ton of tests.
I am going through about 1 qt of oil every 400-500 miles.

Yet, its not shooting out the tail end. I dont have a leak or any signs of dripping. I ran a compression test on all cylinders. Getting about 105-110 PSI on 1 crank, and as high as 190-200 PSI on 4 cranks.

I decided to do a Cylinder leakage test. I am running about 25%to 31%. There is supposed to be about 20% leakage. So its a little higher, however, it is no where near the danger zone.

With the slightly higher readings I was thinking Piston Rings. However, I would venture to guess that these readings, should not be a cause for concern.

I did run a Bore scope on all cylinders, and noticed a very excessive amount of "carbon" build up on the walls and atop of the pistons. I am gonna run some B&G 44K on it with some "Supreme-o" gasoline. See if this burns it away.

Still, how can I be chewing up this much oil. This baffles me... I cannot figure out where it is going...

How long have you been loosing oil at that rate??? Sounds to me that the excessive carbon build-up has carboned up the piston rings so they no longer seal properly. Anything else out of the ordinary...???

[simonsi]

Originally Posted by Pseudotropheus

I am going through about 1 qt of oil every 400-500 miles.

I'd suggest some better data on the oil burn rate, no harm in a bit of base science before all the tests.

What is the "about" figure and is it over 400 or 500 miles (no point starting with 25% error in the figures).

How many miles on the engine and has it always burned oil or is this a new issue?

What oil is in it, how long/miles has it been there and what oil was in before the last change?

[Pseudotropheus]

Heres the thing. If I use 1 quart of Lucas along with some Valvoline Full Synthetic. The oil lasts alot longer, and can get through a full cycle. 5W-30

However, if I choose to run just the Full Synthetic, it chews through it in weeks.

I stopped using Lucas the past few months, because of the winter seasons. I am about to start using it again on the next oil change and through the summer.

Tested Oil Pressure today, and its more then adequate.

However, I can also say since getting rid of those crapy Bosch Platinum's, and switching to the NGK Plugs. The car seems to accelerate smoother, and the engine sound seems more throaty.

Hell the check engine light went out, no more misfire codes.
The Oil is still a mystery...

[Canadianbugin]

Originally Posted by Pseudotropheus

Heres the thing. If I use 1 quart of Lucas along with some Valvoline Full Synthetic. The oil lasts alot longer, and can get through a full cycle. 5W-30

However, if I choose to run just the Full Synthetic, it chews through it in weeks.

I stopped using Lucas the past few months, because of the winter seasons. I am about to start using it again on the next oil change and through the summer.

Tested Oil Pressure today, and its more then adequate.

However, I can also say since getting rid of those crapy Bosch Platinum's, and switching to the NGK Plugs. The car seems to accelerate smoother, and the engine sound seems more throaty.

Hell the check engine light went out, no more misfire codes.
The Oil is still a mystery...

I would look at the engine seals.. ie,cam,crank&main.If the engine is not putting out smoke or leaking ,that you can see.It has to be going somewhere...????

[The Cheat]

5w30 is waaaayyyyy too thin for your car.

15w50 is an acceptable year-round oil, is synthetic, and should slow the consumption down to 1 quart every 5000 miles on a 10k drain.

[Pseudotropheus]

When I use Lucas in the winter time, the car doesnt "crank" the way it should. I put the thinner in during winter, and it goes just fine.

I put the Lucas in during summer and its just fine. The recommended oil on it is 5w-30. During cold starts with heavier oil in the case, I get an annoying lifter tick.
Yes, it goes away after its warmed up, but I just dont like the sound.

After taking a look at those hoses and underneath the car. Besides normal road grime, there are no pools building and or noticeable wet spots.

With the excessive carbon build up, I am starting to think those Valve guide seals are starting to go.

As I havent got that far; Is there another test you can run to determine if the Valve guide seals are in fact letting oil past, until their warm enough to expand? It's an inexpensive ( relatively ) easy fix to do, as long as you have a lil spare time and the gaskets.

I also ran the bore scope through it again, and after using the BG 44K decarbonizer, the inside looks a lil' bit cleaner after 21 miles. I will see what it does after a full tank has run through with 92 octane.

I was surprised today to find out that based on specs and procedures, they recommend 91 octane. Weird...

[simonsi]

Originally Posted by Pseudotropheus

Is there another test you can run to determine if the Valve guide seals are in fact letting oil past,

Find a long downhill, run down it with the engine on the overrun (ie no throttle), when you open the throttle at the bottom check for blue smoke out of the exhaust (poss with a friend following).

On overrun the valve seals see a long period of inlet vacuum, if they are leaking then this long period encourages some oil past the seals which builds up and is burnt when you open the throttle and gives the puff of smoke...

[Pseudotropheus]

Originally Posted by simonsi

Find a long downhill, run down it with the engine on the overrun (ie no throttle), when you open the throttle at the bottom check for blue smoke out of the exhaust (poss with a friend following).

On overrun the valve seals see a long period of inlet vacuum, if they are leaking then this long period encourages some oil past the seals which builds up and is burnt when you open the throttle and gives the puff of smoke...

Ah, backyard way. I like it!

[70autostick]

Originally Posted by 2005Beetle

I'll bet your problem fixes itself with this oil change. I'm thinking someone put a wrong weight in last time and that's the cause of your disappearing oil. I had the same thing with power steering when I accidentally put the wrong fluid in.

BTW: My local VW dealership sent me a reminder to bring the bug in for an 80k-mile service. Should I bother or can I handle it myself?

Dude,you are awesome,I was wondering where you went ,yes,take it in for service bro.