2005.5 Jetta TDI losing massive amounts of oil, looking for ideas

Rezer

Member
Joined
Nov 27, 2006
Location
CA
TDI
2006 Jetta TDI
My Jetta has 320,000 on the odometer, and after some engine work it's now losing an incredible amount of oil and I can't figure out where it's coming from. It's losing on the order of 2-3 quarts every 200 miles. None of it is coming out below the car, it's all going out the tailpipe, but I've inspected the turbo and see nowhere near the amount of shaft play that would be required for it to dump this amount of oil. A synopsis of how I got here might be helpful, so apologies in advance if this gets a bit long winded...

To start with, the car had been pressurizing the coolant reservoir for a while, and I just put up with having to top it off every month or so. Eventually it got bad enough that I sucked it up and pulled the head to replace the head gasket. I cleaned the **** out of the block and the head, using a very fine grit honing block on the block and a roloc disk on the head. I checked whether the block and head were warped with a machinist's straight edge, everything looked great. Slapped the head back on the car, bolted it all back together, drained the oil, refilled it, etc. After a bit of cranking it started right up, everything seemed fine.

Fast forward a couple days, and while I'm about 100 miles from home the turbo starts whining...badly. I thought I could make it the rest of the way home before things went too far south, but before I managed to do so oil was being dumped out the tailpipe so fast that I was leaving a smokescreen behind me. So I pulled over and got a tow the rest of the way home. I probably drove it a little longer than I should have, but nothing catastrophic seemed to have occurred. I pulled the turbo out and sure enough the shaft was just flopping all over the place, and I assumed I had missed something in the intake that impacted the compressor wheel and knocked it out of balance. So I bought a new CHRA for the turbo from turborebuild.co.uk and installed it, in the process cleaning out all the intake piping, draining a ton of oil from the intercooler, flushing the intercooler, etc. Started it up, calibrated the turbo VNT stopscrew using a boost gauge tapped into the exhaust manifold, and everything seemed fine. However, within 5 miles of driving I'm seeing oil under the vehicle. Hoping it was just residual I think I went a total of maybe 40-50 miles or so before deciding that something isn't right. The oil was coming from the not-quite-tight-enough exhaust clamp that joins the turbo to the downpipe. I pulled the turbo out and the brand new CHRA seemed to already have a large amount of axial play, to where it would juuuust contact the housing if I pushed it to the side.

At this point I started thinking maybe my oil pump is just not keeping up, or maybe I have some grit from honing the block still in the oil pan acting as an abrasive. So I dropped the oil pan, replaced the oil pump, the pump chain, the crank bearings and the connecting rod bearings for good measure. There were one or two that were a little scored, but nothing major, and I saw no signs of residue in the oil pan or damage to the crankshaft itself. I put everything back together, put the factory original turbo back on the car that had been sitting in the garage, re-tuned it back to factory settings, and started it back up. Smoke was still coming from the exhaust, but I crossed my fingers that it was just residual oil being blown out from the exhaust. That didn't pan out. It kept right on smoking, and I soon found out it was losing just an obscene amount of oil. Pretty soon it started missing periodically as well, within a small amount of local driving just to check out how things were running.

I've inspected everything I can think of, and while there is still a lot of oil in the exhaust it doesn't seem to be coming from the turbo. I don't have a vacuum leak that I can tell; I can hear air being sucked in the line when I remove the vacuum hose from the back of the valve cover 30 minutes after shutting off the engine. The camshaft and valves all look good, I don't see any fuel leaks around any of the fuel injectors, and the tandem pump, while original to the car, doesn't seem to be mixing fuel and oil at all that I can tell (and to my understanding that tends to pump fuel into the valve cover, not oil out into the fuel). I did a leak down test (while cold, oil pan off) and all the cylinders were testing around 95%. The compression test (while hot) looks a lot worse, reading 440, 300, 410, and 350, but even so the blowby does not seem to be that extreme, and the intake does not seem especially oily. I ran some logs of the injector compensation values and those numbers are just...all over the place. I can't make sense of them, and even it it were the injectors how would it be losing so much oil? Also, the timing measures 0.5 advanced.

Does any of that give any clue to where this oil may be leaking out from? None of this makes any sense to me at this point, and every time I have another bright idea about what might be the cause it just winds up being another dead end. I really wish I had replaced the rings while the head was off, but I'm having trouble convincing myself it's possible to lose that much oil past the rings.
 

Seatman

Top Post Dawg
Joined
Apr 23, 2010
Location
Scotland
TDI
2007 Seat Alhambra 2L tdi
Maybe there's been a problem with the oil supply to the turbo and it's damaged it. One of the things with a new turbo is finding out what went wrong originally that caused the problem to start with.

If it's coming from the exhaust I think it will be the turbo, I think it maybe got a bit starved initially and it's now damaged.

You should have some play as the shaft floats on a film of oil when running but nit to the extent you can almost put the wheel against the housing.
 

Rezer

Member
Joined
Nov 27, 2006
Location
CA
TDI
2006 Jetta TDI
Maybe there's been a problem with the oil supply to the turbo and it's damaged it. One of the things with a new turbo is finding out what went wrong originally that caused the problem to start with.

If it's coming from the exhaust I think it will be the turbo, I think it maybe got a bit starved initially and it's now damaged.

You should have some play as the shaft floats on a film of oil when running but nit to the extent you can almost put the wheel against the housing.
I put in a new braided oil supply line when I first swapped out the core of the turbo, and when I changed the oil pump I pulled the entire filter housing and made sure nothing was in there obstructing it. I checked the oil flow from the end of the braided line while cranking, and while it made a mess all over the engine compartment it sure didn't show any signs of obstruction. I saw how bad the first turbo got (and how quickly it did so), and the turbo that's on there now is showing none of the same symptoms. The end play is acceptable and it's still boosting like a champ. The oil also seems to be all over the inside of the exhaust manifold, so unless it's traveling upstream from the turbo I can't see that being the primary source.
 

Rinderle_77

Member
Joined
May 29, 2018
Location
GJ, CO
TDI
2000 Beetle TDI, 2015 Audi Q7 3.0TDI
I would say it's the turbo, but you have oil in the exhaust manifold. That would then tell me that it's either the rings, or valve guides. Leaning more towards valve guides. Which if they're that bad, it would give you your low compression numbers, pass a substantial amount of oil (especially under vacuum when coasting in gear) and could cause some of your other erratic diagnostic symptoms.
 

Rezer

Member
Joined
Nov 27, 2006
Location
CA
TDI
2006 Jetta TDI
I would say it's the turbo, but you have oil in the exhaust manifold. That would then tell me that it's either the rings, or valve guides. Leaning more towards valve guides. Which if they're that bad, it would give you your low compression numbers, pass a substantial amount of oil (especially under vacuum when coasting in gear) and could cause some of your other erratic diagnostic symptoms.
While I had the head off I did replace the valve stem seals, but I didn't do anything to check the guides themselves. Would the new seals be irrelevant with worn valve guides? I've pretty much given up at this point and I'm planning on pulling the head back off to try to get a better idea of what's going on. Is there an easy method of checking valve guide wear, and are they something that can be replaced without access to anything much more advanced than a shop press?
 

Rinderle_77

Member
Joined
May 29, 2018
Location
GJ, CO
TDI
2000 Beetle TDI, 2015 Audi Q7 3.0TDI
I can't say for sure on this engine (head), as I haven't personally had one torn down. Most of the stuff I've been into is much larger ie. heavy construction equipment, class 8 trucks, large stationary powerplants... which often require use of dry ice or liquid nitrogen to shrink parts to have clearance to press them in.

That said, if there is too much slop in the guides, the seals may not be able to stay in contact with the valve stems and alow oil to pass. Sadly, you'll probably have to pull the head to be able to measure the guides.
 

Rezer

Member
Joined
Nov 27, 2006
Location
CA
TDI
2006 Jetta TDI
I've been pretty much resigned to the fact that I'm gonna have to dismantle it for a while, just don't want to miss anything while I have it apart.

I started taking it apart today, and I just fired it up with the turbo/exhaust manifold off. The #2 cylinder is blowing a large amount of whitish smoke when first fired up, which clears up for the most part after a few seconds, and then it starts blowing it out again with any amount of throttle. I assume there's going to be issues with the fuel ratio with the turbo completely off the car, but I thought it strange that it was only the #2 cylinder smoking to any degree. Would that indicate an issue with that cylinder specifically, or am I assuming too much?
 

Rezer

Member
Joined
Nov 27, 2006
Location
CA
TDI
2006 Jetta TDI
Ok, quick update on where I'm at, I got the head off and this is a photo after wiping some of the coolant off since I clearly didn't drain it well enough:



Given that all the cylinders show some signs of burning oil, and the intake piping has no oil other than what's expected from the CCV, would it be safe to say this rules out the turbo burning oil on the exhaust side? The turbo looks fine to me, but when you say a TDI's losing oil the first culprit is always the turbo and I'm far from an expert on this stuff.

Now the valves themselves do wiggle a little back and forth, but I don't really have any way to quantify it. I did notice a very slight shelf that's only just able to be felt with a fingernail on the intake valves, and below this shelf the valves measure a nominal 7.0mm with my el cheapo calipers:



And above the shelf I'm getting around 6.91-6.92mm worst case:



This seems pretty excessive to me given how hard these valves must be as compared to the valve guides, which are probably worn to an even greater degree. Would this amount of wear be enough to warrant replacement of the valves as well as the guides, and is it likely sufficient to explain losing a quart of oil every 60-70 miles? I'm going to also replace the piston rings anyway, but I'm interested in finding out exactly what's been fucking me over all this time, you know?
 

Chad.

Active member
Joined
Nov 24, 2012
Location
Edmonton
TDI
2006 Jetta TDI
If you've gone this far wouldn't hurt to put some new valve guides and seals in especially with a car that has 320,000 miles on it but I'd find out what the wear spec is first . Won't do you much good if your cylinder walls are egged out though if that's the source of your oil consumption. Just had the head off my 2006 jetta TDI and noticed a lot of build up in the intake exhaust runners. Pretty sure the seals are going but didn't bother to replace them as I didn't have the special spring compressor and don't have any oil consumption issues. If you do replace the guides please post some pics I'd be curious to see how they re done on the BRM heads
 

turbocharged798

Veteran Member
Joined
May 21, 2009
Location
Ellenville, NY
TDI
99.5 black ALH Jetta;09 Gasser Jetta
The two main places these engines usually use oil is rings and turbo. Valve guides won't leak oil in the combustion chamber because there is no vacuum on either the intake or exhaust sides of the valve. Both are under pressure. The way the head looks there is definitely oil passing through the engine. I would say either cylinder/rings or the cold side of the current turbo is dumping oil in the intake.
 

Rezer

Member
Joined
Nov 27, 2006
Location
CA
TDI
2006 Jetta TDI
If you've gone this far wouldn't hurt to put some new valve guides and seals in especially with a car that has 320,000 miles on it but I'd find out what the wear spec is first . Won't do you much good if your cylinder walls are egged out though if that's the source of your oil consumption. Just had the head off my 2006 jetta TDI and noticed a lot of build up in the intake exhaust runners. Pretty sure the seals are going but didn't bother to replace them as I didn't have the special spring compressor and don't have any oil consumption issues. If you do replace the guides please post some pics I'd be curious to see how they re done on the BRM heads
I couldn't find a wear spec for the valve stem itself, but did find a VW workshop manual that says the valve side to side rocking limit is 1.3mm. I don't have a dial gauge on hand at the moment, but with what I have I'm able to put the current valves at around 0.6-0.8mm of travel when rocked back and forth as specified in the manual, not great but not wildly out of spec as I had thought it would be. I thought the spec would be more like 0.2mm or something, so seeing that over 1mm would still be within tolerance was kind of surprising. I still want to replace the valves and guides, but the fact that I can't really find any how-tos for the valve guides makes me a bit skittish about the whole ordeal. It sounds relatively straightforward from what I can find on other engines, but I don't want to get the current ones out and then find out it's a total bear getting them back in correctly.

The two main places these engines usually use oil is rings and turbo. Valve guides won't leak oil in the combustion chamber because there is no vacuum on either the intake or exhaust sides of the valve. Both are under pressure. The way the head looks there is definitely oil passing through the engine. I would say either cylinder/rings or the cold side of the current turbo is dumping oil in the intake.
The turbo is totally clean on the intake side, and the intake piping has just the oil from the CCV, so at this point I'm pretty confident the turbo has nothing to do with it.

On the topic of rings however, I did get the pistons out, and the cylinder walls look pretty smooth with maybe just a hint of crosshatching left. There's also no noticeable ridge at the top of the ring contact area, and the ring gap is identical at the bottom and near the top of the bore, so I'm assuming the cylinder is not significantly worn (I left my bore gauge in my other pants...).


I started taking some measurements on the #2 piston since it seemed to be smoking more than the others. Here's what I came up with:

Compression ring 1:
Gap: 0.88mm Wear limit: 1.0mm
Ring to groove clearance: 0.28mm Wear limit: 0.25mm

Compression ring 2:
Gap: 0.9mm Wear limit: 1.0mm
Ring to groove clearance: 0.10mm Wear limit: 0.25mm

Oil ring:
Gap: 1.9-2mm (stacked feeler gauges...) Wear limit: 1.0mm
Ring to groove clearance: 0.08mm Wear limit: 0.15mm


So the compression rings are on the far end of not great, but mostly within spec. That oil ring though is waaay out of spec as far as the gap goes. Is this the smoking gun I've been looking for? Or just another contributing factor on an engine that just wants to call it quits?

By the way, the piston itself looks to be in fairly good shape, but I don't have the tools to measure it or the cylinder bore currently. Is there a way to measure the piston to cylinder clearance without picking up a bore gauge and a largish micrometer, or am I going to need to bite the bullet on those? Pictures of the #2 piston below, because why not:


 
Last edited:

Chad.

Active member
Joined
Nov 24, 2012
Location
Edmonton
TDI
2006 Jetta TDI
At this point 320,000 miles sounds like the engine is simply worn out, that's pretty good I would be happy if my car gets that kind of mileage. If it were me and I wanted to really keep the car I would pull the engine take it to a machine shop get the bores punched out new rings/oversized pistons basically rebuild the entire engine. I'd do the same for the head as well and you'd probably be good for another 320,000 miles but will the rest of the car be? It comes down to a question of cost/benefit analysis that you need to decide. Is your car's condition worth the time expense and effort or is it time to pull the plug? Just my 2 cents of course.
 

Rezer

Member
Joined
Nov 27, 2006
Location
CA
TDI
2006 Jetta TDI
At this point 320,000 miles sounds like the engine is simply worn out, that's pretty good I would be happy if my car gets that kind of mileage. If it were me and I wanted to really keep the car I would pull the engine take it to a machine shop get the bores punched out new rings/oversized pistons basically rebuild the entire engine. I'd do the same for the head as well and you'd probably be good for another 320,000 miles but will the rest of the car be? It comes down to a question of cost/benefit analysis that you need to decide. Is your car's condition worth the time expense and effort or is it time to pull the plug? Just my 2 cents of course.
I get where you're coming from, and you're absolutely right that the car's condition does not warrant dumping a bunch of money into fully rebuilding the engine. However, it ran very well up until I changed the head gasket and subsequently blew the turbo as a result. The oil problems cropped up immediately after that, and I've already replaced most of the other potential wear items from contaminated oil. If I can get away without reboring the block, just replacing the rings and valve seats themselves are not very expensive at all. I'm hoping to just get by and wring another 100k or so out of the engine if I can just sort out the source of the oil loss. I'm not looking for a brand new engine, just the engine I had before it suddenly went tits up. The car's a beater for sure, but I'm not ready to get rid of it just yet.
 

turbocharged798

Veteran Member
Joined
May 21, 2009
Location
Ellenville, NY
TDI
99.5 black ALH Jetta;09 Gasser Jetta
Take a ring and check the bore in multiple places and see if the gap changes at all. The bores tend to taper out which will cause oil consumption. If the gap is pretty consistant then I would be inclined to give it a hone and re-ring the pistons.
 

Rezer

Member
Joined
Nov 27, 2006
Location
CA
TDI
2006 Jetta TDI
Take a ring and check the bore in multiple places and see if the gap changes at all. The bores tend to taper out which will cause oil consumption. If the gap is pretty consistant then I would be inclined to give it a hone and re-ring the pistons.
That's kind of the direction I wanted to go, but I was so caught up looking for causes of oil consumption I completely failed to notice this little gem on cylinder 2:



So...that's not great. I guess it hydrolocked at some point when the turbo was dumping oil in the intake, and that would explain the excess smoking from cylinder 2 and the feeling that it had kind of a miss, but picking up a used conrod and balancing the set isn't exactly the end of the world.

The bigger problem, as I understand it anyway, is that when I took out the wrist pin to have a look, #1 looks okish, but #2, #3, and #4 all have 2 ridges on the pin on either side of the top bushing and the conrod rocks back and forth significantly, with a very obvious gap between the inside of the conrod bushing and the wrist pin. Like it doesn't look worn, it looks like the metal has actually deformed and raised slightly around the sides of the bushing. Is that a common failure mode for these? The bushing itself doesn't seem very worn, because it still fits relatively snugly in the #1 wrist pin, but hell if I can find a replacement for the bushing anyway. Is it even possible to replace the top conrod bushing on the beveled rods in a BRM engine? Or is the only remedy a new set of rods?

The cost of the wrist pin + bushings alone is nearly as much as just picking up new pistons, so I'm leaning in that direction, but I'm picking up some tools to accurately measure the bore before I start going down that path. I don't wanna drop $400-$500 bucks on parts and find out the cylinder wasn't actually in great shape after all, since I could just pick up a used running engine for what, like $1100 these days?
 
Last edited:

Rezer

Member
Joined
Nov 27, 2006
Location
CA
TDI
2006 Jetta TDI
Well, I got some measurements in today, and they look well within the wear spec, but there is some amount of difference between the traverse and longitudinal measurements...do any of these numbers look concerning to where it would be inadvisable to leave the block as is? A new block is speced at 3.1303, with a wear limit of 3.13425. The numbers represent the top, middle, and bottom of each bore, respectively:

Cylinder 1:
Traverse Longitudinal
3.1320 3.1305
3.1320 3.1305
3.1320 3.1305

Cylinder 2:
Traverse Longitudinal
3.1310 3.1310
3.1310 3.1305
3.1310 3.1305

Cylinder 3:
Traverse Longitudinal
3.1320 3.1310
3.1320 3.1310
3.1320 3.1310

Cylinder 4:
Traverse Longitudinal
3.1320 3.1310
3.1320 3.1305
3.1320 3.1305

I'm pretty new to measuring cylinder bores, so I performed each measurement several times and kept the highest result rounded to the nearest 0.0005. I wouldn't be overly shocked if any of these were off by about that much, but I wasn't having too much of an issue with repeatability. The most any cylinder is out of round is 0.0015, which seems pretty insignificant to me, but I'm speaking from my complete and utter lack of expertise on this matter...
 
Top