Increased oil consumption on highway?

Did a 500 mile trip this weekend. Mostly highway miles with the a/c on and temperatures in the mid 80's. With the seats folded down the car was pretty heavily loaded with camping gear and coolers full of food and beverage. Left the house and oil level was near the top of the dotted lines. I am at 88K and therefore 8K miles in on this oil and I've already added about 1 quart. I also have a Provent with about 6 inches of tubing off the bottom which was emptied before I left.

After the 500 mile trip averaging about 70mph, the oil level dropped a few marks on the dipstick and the tube off the Provent was nearly full. This is much more consumption and blowby than I typically see. Are there any issues I should be checking for? I fear if I had gone another 500 miles I would have been looking at dumping the tube and adding more oil... not good! I've never done an oil analysis but plan on doing one this time around.

Any ideas?

Is the intake clear and air filter clean? It could be sucking oil from the CCV if you are getting a strong vacuum after the air filter.

As far as I know it should be clean and clear. The filter is fairly new and the snow screen unobstructed.

So excess vacuum could cause the crank case pressure to increase? Is there a simple way to tell if that is happening?

I understand that what happens is that the turbo want's it's air and if it doesn't get enough volume through the intake hoses it will cause a stronger than normal vacuum from the crank case vent and actually suck the oil that is splashing around in the cam area through into the intake.

What is a Provent CCV? The CCV vent that comes stock has a rubber diaphram that sucks in if there is too much intake vacuum, and blocks that from happening. I don't know how a Provent works but if you say the hose was almost full after the trip then that would be my guess.

The Provent is an air/oil separator. It is plumbed off of the CCV outlet and separates the oil from the air and then it is plumbed back to the intake.

What is a mark? It is not a unit of measure found in or on my car. OK, maybe not really. My dipstick has a high mark and a low mark which is about a quart. I can drive 10,000 plus miles between oil changes and I do not have to add oil. I drive on the highway at legal speeds almost every time I drive the car.

If the drain hose was 6 inches long and you had the tube filled up it is not a big deal. The Provent itself has a few cups of capacity internal. Sometimes the Provent collects lots of oil. Other times not so much. Do the math. 6XPiRsquared is what? 1.18 cubic inches. multiply by .55411 (Pocket Ref by Thomas J. Glover, Sequoia Publishing) to figure out how many ounces that is. Not much oil in that 6" tube.

Blowby is not measured by the amount of oil your Provent collects. Nor is it measured by the amount of oil your car consumes.

Have you ever gone to the racetrack and watched a road race with boxer engined Porsche race cars? They burn oil a fair bit. I bet when they are driven at 70 mph with cooler oil they consume less oil. A friend had a delivery truck that would burn oil like crazy when his employees drove it at 80 mph loaded with a few tons of materials. When driven at a legal speed limit the oil consumption went down. 70 mph is not that fast or hard for a VW unless you are carrying a lot of luggage on the top of the car or towing a brick shaped trailer.

The crankcase vent system works on a venturi principle I think. More air into the engine intake causes greater potential flow from crankcase vent. Oil cover and the hockey puck (on my car) restrict the amount of air flow to a degree. I suspect if you hooked a vacuum guage up between the valve cover and the Provent you might not even get a reading.

If you are trying to say you used 1.5 quarts of oil on a 500 mile trip then you have something to worry about. If you are saying you used 3 ounces then you are worrying about nothing.

I can camp for a week with a 50 pound bag that has my tent, bag, clothes and sleeping pad. Add some groceries and a cooler and you should only have a 100 pounds of crap unless you are bringing the kitchen sink. OK, the big Coleman cook stove is 20 pounds with fuel som maybe 120 pounds of junk.

squebel said:

Did a 500 mile trip this weekend. Mostly highway miles with the a/c on and temperatures in the mid 80's. With the seats folded down the car was pretty heavily loaded with camping gear and coolers full of food and beverage. Left the house and oil level was near the top of the dotted lines. I am at 88K and therefore 8K miles in on this oil and I've already added about 1 quart. I also have a Provent with about 6 inches of tubing off the bottom which was emptied before I left.

After the 500 mile trip averaging about 70mph, the oil level dropped a few marks on the dipstick and the tube off the Provent was nearly full. This is much more consumption and blowby than I typically see. Are there any issues I should be checking for? I fear if I had gone another 500 miles I would have been looking at dumping the tube and adding more oil... not good! I've never done an oil analysis but plan on doing one this time around.

Any ideas?

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By "mark" he means the rows of dots I think.

Again, to me, it seems excessive. I have more oil consumption than it seems most people experience and that last 500 mile trip sorta freaked me out. I wouldn't think I should see any consumption on just 500 miles, right? And Bob is correct, I'm referring to the rows of dots on the dipstick. At the same time the amount that was filtered out by the Provent seemed a bit much as well. I'm just wondering if I'm having some other kind of issue that I should be checking for. Could the Provent be causing excessive crankcase pressure? Could the age of the oil have an effect?

And yes, we usually take the kitchen sink. I've roughed it 100's of times. When I can take the kitchen sink, I do. ;-)

No, Provent cannot cause crankcase pressure. The Provent is basically a jar with a hose entering and leaving. To make pressure you need heat like when you boil water or something that turns and has some sort of impeller or piston. You do not see any of those things in a Provent. The only thing that can cause crankcase pressure is leaking rings or valve guides.

Did you check the oil level when the car was parked in exactly the same place and the engine had been shut down for the exact same time or at least a few hours after the engine had run?

How many miles on your car? What is a typical drive? I usually drive my car an hour 1 way. That is fairly easy on oil consumption. I have no idea how my engine was broken in as my salesman tranfered it from another dealer to his shop. The car had a few hundred miles on it when I got it.

I have had engines in used cars where someone ran the oil level low and the cylinders were scored. Oil consumption was greater than it should have been. I wasted plenty of money on VWs trying to reduce oil consumption. On my Toyotas changing valve stem seals reduces consumption significantly. Problem is that I have to remove the head to do that task. VW has some rediculous oil consumption rating of maybe a quart every 1,000 miles. Not many are happy if their TDI is burning oil at that rate.

You might want to remove the Provent because it will cause you to continually freak out over the quantity of oil it can hold. I think I have drained a cup or more out of my Provent on occasion.

And you're certain there are no new leaks? I know that sounds trivial but just checking.

The car has 88K on it all by me, all high quality 505.01 oils, and followed break-in procedure to a "T". My normal driving on a daily basis is only about 25 miles, but I don't get to sustain a lot of consistent highway miles and speeds. It seems like I start to consume more oil the more miles I add onto the present oil change. I suppose it's possible my daily driving it much harder on my oil than most people's... that is why I'm finally going to have an UOA done.

I measured the amount of oil in my tube and there was about .5oz. I'm thinking I went through about 5 or 6 oz on that trip just by looking at the dipstick.

If I wanted to find out if I had rings going out, I would need to do a compression test, right?

And yes, there are no leaks anywhere. I keep the engine clean and make sure there is nothing leaking. I guess it would probably be worth checking the intercooler to make sure it's not full of oil.

I had the CCV open earlier with the engine idling and there was quite a bit of air pressure coming out of that thing. I guess the only way to find out what is too much would be to put a gauge on it and measure the pressure. If I put my hand over it for a few seconds and then let off, it lets out a lot of air in a big whoosh.

As far as removing the Provent... I plan on leaving it on. I'm glad to know that the oil is going there instead of back down the intake.

how many miles on the turbo?

Remove your oil fill cap, plug it with your hand. If you feel pressure there is a big problem. You should have little to no pressure. If you do then you also have low compression on at least one cylinder. I can't imagine that you have that kind of problem. I've never heard of a TDI having a compression problem. 150,000 miles on mine and I have never "added" oil between changes.

Original turbo. I will check the pressure out of the oil fill when I get home to the car. I had it off earlier and there definitely was air coming out, but how much is too much?

If you can feel it, it's too much. If you have another vehicle start it and do the same test. You'll know then. Good luck. Keep us updated.

Take the provent off!

Those things create more issues because people freak out when water is captured which would have otherwise been burned off by the motor in the CCV.

More than likely the stuff in your provent was water or a combination of water and soot. A long drive will cook off the water entraped in the engine and it will condense in your provent.

I personally tell people to never install any catch can on the CCV system. If you look in your intercooler you still have the same amount of oil as you did before the installation of your catch can.

Nearly all the oil comes from the turbo NOT the CCV.

High speed driving will increase oil consumption slightly due to the oil mist from the pistons oil injection system.

My point is they are a waste of time and increased complexity that does not belong on these engines.

I used to subscribe to them but no longer do.

Oil in the intake WILL NOT hurt anything, besides that there is nothing you can do about as long as you have a turbocharger!

DBW: Finally someone that understands. I do think though that he still has a problem, his quote "there definitely was air coming out". If he has positive airflow out of the oil filler cap there is a problem. JMO.

Karl

Ok. Taking DB's recommendation (knowing he know's his junk), I took the Provent system off for a while and put the plain ol' plastic pipe back on.

Have people done tests on the stuff that the Provent is able to separate? Besides having a UOA performed on the contents, how can I actually be sure it's more water than oil?

Back to the pressure situation - Yes, there is quite the amount of air chugging out of the oil fill. I've read in the past about that pressure and trying to find out what is too much, but not sure I've found a definitive answer.

Things that create the positive air flow thru the motor:

-Vacuum pump: Provides a CONTINIOUS flow of air PUMPED into the crankcase to provide vacuum to the brakes, ventilation system, turbo servo, Anti-shutter valve, vacuum accumulator. Air is drawn in from the airbox after the filter and provides clean air for the vacuum pump.

-Turbo seals(Intake and exhaust): under boost air passes accross the turbos compressor seal. At idle and all operating regimes exhaust gasses pass accross the turbine seal and both route via the oil return line back to the crankcase. You are making something that is normal into a problem that does not exist

-Normal Blow-by: you own a diesel, each cylinder generates as much as 2,800 psi of combustion pressure...YES some will leak past the rings and into the crankcase.

My point is that AIR FLOW from the engine is MANDATORY otherwise you will blow the seals out of the block! A TDI because of the vacuum pump will have 3-4 times the outflow of a gasoline engine since they generate all their vacuum via the intake manifold.

You don't have any issues with the motor, if anything the more you look into the Provent the less you are going to sleep...take the thing off the car and let the car run the way it was designed. You are creating a problem from something that is normal, simply put your engine is perfectly fine.

Oil consumption will increase with sustained high speed driving, its the nature of the beast.

I walked out and started my engine which has 230,000 miles on it. I can hold a paper towel a foot away from the fill hole and it gets blown a good bit. I am agreeing with DBW.

As a point of reference my oil level is down to the bottom of those dots some people reference but above the lower kink mark. I think that oil change is 8-9,000 miles and it was not up to the top bend. No oil added.

I have always found oil in the intercooler. With the Provent and without. Once agan agreeing with DBW.

Is there enough oil in the IC to pour out?

Don't mean to hijack, but I got one for you guys.

As some know, I recently did an engine swap and installed a VNT 17. I've noticed that my engine is using quite a bit of oil. I can go from my home to Edmonton and back (about 600Km) and I'll use enough oil that it will go from the top of the hatch marks on the dipstick to about 1/16" below the lowest hatch mark.

Now, I noticed that when I got the engine started for the first time, at least 1 lifter was ticking a bit. Not too loud, but I could hear it. I know for sure that it isn't leaking oil. There isn't any marks on the skid plate and there are no drips anywhere on the engine. Nor is there any oil in the coolant, so it burning oil. I do notice that I get a bit of a bluish haze behind me when I accelerate hard.

Now I'm thinking that there is a chance that maybe the valve guide seals are bad. Is it a good chance those seals are causing my problem?

Input is welcome.

Bob_Fout said:

Is there enough oil in the IC to pour out?

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If you have enough to pour out the issue is how your are driving and never getting "On-boost".

Pooled oil in the intercooler is the result of not driving the car properly and the oil from the associated systems isn't being blown clear.

Drivbiwire said:

If you have enough to pour out the issue is how your are driving and never getting "On-boost".

Pooled oil in the intercooler is the result of not driving the car properly and the oil from the associated systems isn't being blown clear.

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Yup, that was my point in asking If roadhard has oil in the IC, he's not flogging it enough

Bob_Fout said:

Yup, that was my point in asking If roadhard has oil in the IC, he's not flogging it enough

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I think I'll name my car Molly.

I had to google that one

Yes, I am not a flogger of that car. It occasionally gets some full throttles but not often. Grandma driving it. I have some annoying surges at full throttle I need to chase down so full throttle third gear does not bring joy. It starts with new vacuum lines but I have been too cheap to order those.

My little truck on the other hand gets flogged pulling the horse trailer or equipment trailer. I use every bit of torque and HP it has. Of course it has some serious issue so it is down on hp and torque. Starting to throw parts at it which is sort of expensive. Think of all the cool bicycle parts I could get if I did not have to maintain vehicles. I also need to split the tractor to grease up the input shafts. Plural as there is the tranny input shaft and the pto input shaft.

Bob_Fout said:

Yup, that was my point in asking If roadhard has oil in the IC, he's not flogging it enough

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737tdi said:

DBW: Finally someone that understands. I do think though that he still has a problem, his quote "there definitely was air coming out". If he has positive airflow out of the oil filler cap there is a problem. JMO.

Karl

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Oh, contraire... There's a surprising amount of flow from the valve cover @ idle. It was a matter of some concern to me until I found out the vacuum system is also dumping into it. Now I realize it's normal. You absolutely should feel some pressure coming from the uncapped oil fill spout, an alarming amount if you're used to gassers.

Because of the high pressure at the oil fill, I'm assuming at least that is the cause, I get some oil weaping through the cap and down onto the top of the engine. It's not so much that it is like dripping off the back of the motor but it's more of a film that needs to be wiped off. Sometimes it is worse than others. Should I get a new oil fill cap or would that even help?