03 Jetta TDI Intercooler

The intercooler assembly is wet with oil. I noticed oil seeping from the tubing connections and pulled it apart to find it wet with oil from the bottom of the turbo all the way to the EGR. Don't know if this is normal but suspect that it is not. The oil is not enough to be dripping and leaving puddles. Any info concerning this problem will be greatly appreciated.
Thank you!

A light coating of oil on the inside of the intercooler and related hoses is normal.

It's normal because it's part of normal turbo seal operation to leak a little oil... which makes its way into the intake hosing and intercooler.

"How much is too much" is the difficult question to answer... but in my opinion I would not be concerned if I drained a teaspoon or two any given year from the intercooler (which I do drain annually), and every TDI I've ever had eventually a bit of oily residue creep at the major intake hose joints.

Whether your situation is more or less than that is tough without actually being there... or seeing pictures.

That said, I'd not expect multiple "puddles"... how many miles on your turbo? What's your actual oil consumption like at the moment?

How much oil are you having to add between changes?

The oil does not come from the turbo. This is a very common misconception among members of the TDIclub, for reasons that escape me.

The oil comes from the CCV system and is completely normal. Since the vacuum pump exhausts into the top of the head, that flow needs to be evacuated. Using the turbo suction pulls it into the intake (along with some of the oily mist that is normal inside the valve cover) and that eventually coats everything.

Really now, if the turbo started bleeding oil whenever it wasn't under boost, why wouldn't every TDI that has ever sat in LA traffic have consumed all their own oil long ago? Same for sitting at how many stoplights or traffic jams between oil changes just about anywhere else. It doesn't happen. The turbo does not have "seals" as such, b/c what sealing material do you know that can withstand 150,000 rpm of friction or over 1200 degrees of exhaust gas?

No, the turbo shaft is "sealed" with a pair of thrust washers that have very tight tolerance to the shaft itself. The drain is the path of least resistance away from the turbo shaft and bearing area, and the surface tension of the oil is high enough to keep it from flowing into that thrust washer's tiny clearance while simultaneously cooling the washers and the turbo shaft.

The turbo is *always* spinning though b/c once the oil pressure is present, the shaft is basically in a frictionless environment. Even the slightest puff of air (and the engine's normal intake is quite vigorous) is more than enough to keep it spinning quite rapidly.

My Jetta has 140,000 miles. I do not have to add oil between changes. Thank you for responding. You have made me feel much relieved.

I do not have to add any oil between changes. Thank you for responding. Everything I have heard makes me believe this is normal. I feel much better now.

Geordi said:

The oil does not come from the turbo. This is a very common misconception among members of the TDIclub, for reasons that escape me.

The oil comes from the CCV system and is completely normal. Since the vacuum pump exhausts into the top of the head, that flow needs to be evacuated. Using the turbo suction pulls it into the intake (along with some of the oily mist that is normal inside the valve cover) and that eventually coats everything.

Really now, if the turbo started bleeding oil whenever it wasn't under boost, why wouldn't every TDI that has ever sat in LA traffic have consumed all their own oil long ago? Same for sitting at how many stoplights or traffic jams between oil changes just about anywhere else. It doesn't happen. The turbo does not have "seals" as such, b/c what sealing material do you know that can withstand 150,000 rpm of friction or over 1200 degrees of exhaust gas?

No, the turbo shaft is "sealed" with a pair of thrust washers that have very tight tolerance to the shaft itself. The drain is the path of least resistance away from the turbo shaft and bearing area, and the surface tension of the oil is high enough to keep it from flowing into that thrust washer's tiny clearance while simultaneously cooling the washers and the turbo shaft.

The turbo is *always* spinning though b/c once the oil pressure is present, the shaft is basically in a frictionless environment. Even the slightest puff of air (and the engine's normal intake is quite vigorous) is more than enough to keep it spinning quite rapidly.

Click to expand...

If the vacuum pump is discharging that much air there must be a major leak somewhere. The vast majority of air coming out of the CCV is blow-by. All engines have blow-by. VW diesels going back to the first one in the 1977 Rabbit had oiling issues from the CCV system. The 1980 models had recalls to the dealers to add an extra hose off the existing hose in an effort to deal with excessive blow-by oil. The modern TDI engine has much improved Valve Cover with a plastic baffled cover under it to help deal with the oil mist created by the spinning cam shaft. The combo of oil mist and blow-by (and some vacuum pump discharge) accounts for some of the oil ...... but not all of it!

The Turbo does have seals... The seals are metal expansion rings... very similar to piston compression rings! And, yes, oil will be pushed out around, by, between, etc., the seal! Oil that makes it to the exhaust side is burned. Oil that makes it to the Impeller side is blown into the intake! If you ever disassemble a VNT 15 (or 17) you will see that re-assemble requires force to make the sealing rings contract into the housing shaft hole.

Try this test: Remove the discharge hose on the Turbo of your TDI and drive it down a remote road where it is safe to go slow ... you will be surprised at the amount of oil blows out the Turbo ! With virtually no back pressure, the oil pressure will force oil out and around the seal.... <<<< been there and seen it happen !

Sorry, I have to disagree.

If the oil loss was as bad as you suggest, then each time I have used my TDI for a hotel and let it idle for 8 hours straight with the AC running, I must have lost a massive amount of oil, right? Probably many quarts?

Funny then... On an engine with over a quarter-million miles on it, and a turbo with over 375k miles... I was checking the oil each day on my last big trip (where I ran the engine continuously for about 10 days with only one 18 hour continuous period parked and off) And over 4000 miles on this trip... And it used exactly half of one quart.

That is almost exactly what the engine has used between oil changes for several years now, pretty much no matter how I've been driving it. Obviously your mileage may vary.

It wasn't me that said the Turbo lost lots of oil while idling in a traffic jam, accident on the Interstate, etc. I never said that! I sit one time (winter of 2003) for almost 7 hours due an accident on the Interstate........ cold out, engine idled the entire time! I do not recall having to add oil. (so we agree on that point).

I've started my 2000 Jetta TDI with over 350k miles on it (engine and turbo are OE) never shut it down for up to 15 to 18 hours while driving the 127 Highway Yard Sale (almost every year I've owned it). I leave it idling with the AC on for my doggy. I never noticed any significant loss of oil. Now at 359k miles it does drop almost a full quart between 10k mile oil changes. However, my son drives it as a relay vehicle with his work. The drive is about 250 miles per week! If he flips the relay, it gets about 500 miles on it in one trip during the week. Really not much driving at all.

However, the vast majority of gurus will agree that the turbo is going to pass more oil by the seals (which you don't believe they have) while idling vs on the road driving.

At the end of July, I finished an almost 12k mile road trip with my ALH TDI Vanagon (200k miles on the OE engine). It took almost a quart of oil to keep it topped off (holds a bit over 5 quarts). I was hauling 4 adults, baggage, and pulling a 1200 lb popup camper. The Vanagon transmission gearing has the engine revving at about 3100 RPMs at 70 mph. The CCV system uses an E-vac set-up which actually pulls on the crankcase with a slight vacuum. Which accounts for some of the oil. The Turbo does dump in some oil in the intake system (quite evident upon inspection). ... of which neither is anything to worry about in my opinion.

Your 1/2 quart on the trip you mentioned is about right for the engine and turbo described. No argument there!

But, do the test I suggested. You will be surprised at the amount of oil that will be blown out the boost side of the Turbo.

As for the CCV system, well there is a lot more oil passing through it than most people are willing to admit... and more as the engine becomes high mileage. Combine the oil from the Turbo and it can be a significant source of loss, driving conditions included.

You are both right. The turbo will pass a bit of oil, but its almost unmeasurable. You can stop the oil on the turbine side by using a gapless ring, which I used on my remote mounted turbo van as due to its location, it bled a bit more than I liked.

If you remove the CCV system, you'll virtually stop any oil in the IC system.

Eliminating the CCV system on my ALH in the Vanagon and it did not stop oil from being inside the Turbo pressure piping... It has always been a bit oily but there are no places in the system for it to pool like in the Jetta, Golf & NB.

Below, CCV piping set-up going to the E-vac on the exhaust.



Below, the E-vac bung/fitting between the CAT and glass-pack muffler. (Muffler on the left and CAT on the right). There was too much back pressure to install it upstream of the CAT.



Below, looking down the barrel (upstream) of the muffler. The E-vac produces a small amount of vacuum, thus assists with pulling out crankcase blow-by, suspended oil mist, and vacuum pump exhaust.



The above has been in operation for over 71k miles with no issues. The engine just turned 200k miles and come from MrGutWrench's wrecked vehicle (Jetta, Golf, whatever) via Jimbote. So, the engine history is well documented to be excellent. However, the Turbo does dump in some oil as I stated above. Back in July we rolled up almost 12k miles pulling a popup camper with 4 adults on board. I had to add just under 1 qt of oil to keep it topped off (it holds a little over 5 qts.)

So, either my Turbo is bad or they dump more oil into the pressure pipe than we realize. I have no plans to change the Turbo.

Interesting. Thank's for the insight.

Interesting setup on that CCV tube. I gather you haven't had any issues with popping your rear main seal - that is the main problem with allowing the CCV to hold any pressure. From the CRD side, the common logic is that we don't want more than 1psi of pressure, or less than [the equivalent of -1psi] inches of vacuum b/c it will cause problems. But the vacuum discharge into the crankcase is indeed most of that flow b/c you have a constant flow of fresh air into the vac system from the brake bleed and the turbo solenoid bleeds.

There is also bound to be blow by that passes the valve guides, and that would add to the oily mist by splattering the oil from the valve guides up into that baffle in the top of the valve cover. I love that baffle by the way - I made the mistake of opening the oil fill cap on one of the Jeep CRDs while it was running.... Now I have a white shirt that looks like a dalmatian. Oops.

I think if we were able to completely scrub the intake track from turbo forward, degreasing the entire thing, we would find the barest tiny drip from the turbo under most circumstances. But getting the thing clean enough to tell would be the hard part. If they are only using 1 quart in 5000-10000 miles... That isn't worth the bother to even worry about.

As I stated, over 71k miles with the set-up without any problems.

My Turbo set-up (this is an ALH in a Vanagon) was clean as a whistle from the exit of the Turbo pipe to the Intake, including the Intake......But, almost from day one, it has had some oil on the inside.

This last 11,600 mile road trip pulling a popup camper and hauling four adults is the only time it's taken over a half qt (almost a whole quart) of oil to keep it topped off. The engine handled the load extremely well (Ky to Alaska back down thru the edge of the Rockies to Glacier, Yellowstone, Grand Tetons, Rushmore, Badlands, and home (also drove to the Arctic Circle) ...... did roughly that same trip two years ago.

Before the last trip, I installed a new clutch and my original modded tranny ....... I never saw any indication that the rear seal was leaking, nor the front seal. In fact, my engine is quite clean!

I sort of doubt that the majority of the CCV venting is from the Vacuum pump discharge. I have a Vacuum gauge on the vacuum system. It stays at about 23 inches until I touch the brake pedal...... very seldom drops below 20 inches and rebounds fairly quick. As for the Turbo actuator use of vacuum, I have never been able to notice a change in the vacuum gauge while going thru the gears and observing the Turbo gauge to assure it is operating.

All internal combustion engines have blow-by.... high mileage engines will have more. The Blow-by oil mist in the first generation of VW Diesels was horrible, turbo or non-turbo. The engine oil turns black because soot has ben blown by the rings.

I doubt there would be any blow-by pressure going by the Intake valve guides because of the counter pressure of the Turbo. At idle, the blow-by pressure is going to be quite low. The Intake suction on the CCV system on the OE set-up would be more than adequate to handle blow-by at idle rpms, thus no problems with the Intake valve guides and seals. There might be exhaust pressure go up by the valve stems and past the seal on the exhaust valves... However, I've never seen that to be an issue of major proportions!

Side note: Every VNT15 I've disassembled had gap rings for seals. I'd like to know a source for "gapless" ring seals.

AndyBees said:

Side note: Every VNT15 I've disassembled had gap rings for seals. I'd like to know a source for "gapless" ring seals.

Click to expand...

Trying to find some, might be a custom made thing though.

Interesting info with the E-vac thingy.

The instructions show the 45* angle to be facing down (parallel to the exhaust pipe). It has a small cut in the pipe up from the 45* which is suppose to face upstream for the exhaust to hit and go down and out, thus creating vacuum. As with the orientation I did, the cars of days gone-by had a similar set-up with the 45* angle cut facing toward the rear to pull the crankcase fumes out (elephant trunk style).

Well, as you can see I turned the 45* angle toward the exhaust exit. It seemed to work just fine. I could hold my finger over the end of the pipe while the engine idled and feel vacuum.

Anyway, after about 60k miles and in June before we left for the road trip, I removed the entire exhaust and installed stainless but still used the CAT and Muffler as seen in the photos. I had to have some welding done on the CAT up-stream end. So, I wanted it to be nice and clean for the welder. I pressure washed it, outside and inside. I left it hanging on a fence post in the Sun for several days. ..... It was amazing how much soot was blown out. I assume both the CAT & Muffler. Well, that procedure did not hurt the CAT. It still appears to work just fine (chlorine smell). Also, with the clean CAT & Muffler, using compressed air, I did a few crude tests to see which angle produced the best vacuum. I could really not tell much difference but leaned toward my set-up.

Also, on the road trip, even with two additional people and their luggage on board, the Van got about 1.4 MPGs better than two years ago. I suppose the larger exhaust and clean CAT was responsible. My driving technique was no different. If anything, on average, I drove faster... more 70 MPH.