Troubleshooting Oil Consumption (Loss or Leak)

[defever]

Hello B5 drivers,

I've been noticing oil consumption (loss or leak) for the last 6,000miles; I had it at the "max" when I did my oil change then and it's now at 1/4 on "max - min" zone on the dip stick.

So far the following has been changed, based on oil residue around the area:

Sump gasket (the rubber gasket) (9,000miles ago)
Turbo: oil return pipe gasket (9,000miles ago)
Turbo: intercooler hose from turbo intake to intercooler (the "s" shaped hose out from the bottom of the turbo) (3,500miles ago)
Breather: From the pipe at the block to the valve at the top, including the oil separator (1,500miles ago)

I just checked all those areas again; the surrounding is clean and there's no new sign of oil leak.
I also just checked (from above) and felt around the oil cooler, as this seems another common place for oil leak; luckily, no residue of oil leakage from the oil cooler or filter.

I wiped the oil sump pan 500miles ago and I've yet to check the state of it. When I did this, there was a thin layer of slimy (not gunky) oil all around the pan and a droplet was forming at the sump plug (checked and tightened). The plastic undertray also had some oil residue all over. I did notice a gunky oil residue above the pan gasket and further above from the engine but couldn't locate where or how long since the breather pipe was replaced; the breather pipe was making a mess around it so I couldn't quite figure if the residue is from pre- or post replacement. There's lots of stuff crammed up at NS of engine block so its quite hard to identify.

It's probably worth mentioning that intake pipe at intake manifold has always been oily (enough to drip by gravity if the plastic pipe is removed), but I'm not sure how much oil is acceptable in the intake and how much is too much.

Is there anything else obvious that I can check while I monitor further loss / leak of oil?

Thanks very much for your 2p as always.

Happy motoring.

[Doctle Odd]

Why was the sump off? It doesn't have a gasket it uses sealant and unless its sealed properly it can leak

[niall campbell]

What grade of oil are you using ?

[defever]

Thanks very much both Niall and Doctle for your posts.

The current oil is Triple QX oil 5W-40 full synthetic (VW 505.00 approved) from ECP. It might have been the oil for PD engines, as the container was black not gold as seen on the website. I always ask a garage for annual full service with MOT to maintain FSH record so I don't know what oil is put in.

I'm keen to use Castrol from ECP for next interim oil (I usually do it 6,000-8,000miles or 6months, which ever comes first).

The sump was taken off because the garage noted a leak from the sump at the beginning of the year.
I thought that was the cause of the leak so first, I tried to do it myself and looked at PartBase.org for the sump gasket part:

http://www.partsbase.org/audi/audi-a4-s4-avant-quattro-a4q-eu-1999-8d-x-199-999-10315-cylinder-block-with-pistons-oil-sump/
(http://www.partsbase.org/audi/audi-a4-s4-avant-quattro-a4q-eu-1999-8d-x-199-999-10315-cylinder-block-with-pistons-oil-sump/)
29377

There's couple of parts for sump gasket:
#28: 044103609D (http://www.partsbase.org/parts/aud-044103609d/) Seal
#28: 037115220B (http://www.partsbase.org/parts/aud-037115220b/) Surge lock

I ordered the seal, which I believe is a metallic gasket with rubber lining on the outside. I realised that the sway bar (I think) goes right across the pan and there was no way I was going to do a DIY on it with just axle stands. So I asked, with other things that needed doing, the same garage to replace the gasket. When it was completed, I can see that they've used the seal I ordered as well as white cream / sealant (I don't know what it is). So that's all I know about the gasket replacement.

Is this what you expect to be done, Doctle? I haven't questioned their sealant replacement job until you mentioned it. I don't doubt their workmanship but perhaps something is missing or not done as you would?

Many thanks for your input, as always.

[Doctle Odd]

In order to replace the sump gasket you need to support the engine and lower the subframe. I don't recall ever seeing an actual sump gasket for an AFN the gasket you linked seems to be for a turbodiesel rather than a TDi. The white sealant isn't automotive it sounds like household silicone. I've seen white sealant on many engines it doesn't stick it doesn't handle heat well and oil weeps out of it

[Doctle Odd]

In order to replace the sump gasket you need to support the engine and lower the subframe. I don't recall ever seeing an actual sump gasket for an AFN the gasket you linked seems to be for a turbodiesel rather than a TDi. The white sealant isn't automotive it sounds like household silicone. I've seen white sealant on many engines it doesn't stick it doesn't handle heat well and oil weeps out of it

Read the info posted by Crasher in this thread

Oil Sump/Pan removal [Archive] - VW Audi Forum - The #1 VW Group Community (http://www.vwaudiforum.co.uk/forum/archive/index.php/t-90316.html?)

[defever]

Thank very much Doctle, interesting information.

I've Googled the rubber sealant part number and AFN and it looks like some known websites has a reference to this rubber sealant for AFN:

http://www.germanautopartsdirect.co.uk/AUDI-A4/S4/RS4-upto-2001-ENGINE-&-CLUTCH/c1_23_84/p1555/ENGINE-OIL-SUMP-PAN-GASKET-044103609D/product_info.html

Volkswagen - M >> AHU 760 000* M >> AFN 866 421 seal (044103609D) Teile Katalog (Pats Catalog) (http://www.germanautopartsdirect.co.uk/AUDI-A4/S4/RS4-upto-2001-ENGINE-&-CLUTCH/c1_23_84/p1555/ENGINE-OIL-SUMP-PAN-GASKET-044103609D/product_info.html)

The rubber sealant was ordered from TPS so they would've mentioned if it isn't needed for AFN engines.

This could be one of those mystery parts...

I will check the sump gasket again and see what's happening. I'm convinced that the white sealant is a silicone sealant, but not sure if it's VAG approved or whether it's one of the garage's generic sealant.

Thanks very much for your 2p and I'll have a look under the bonnet sometime this week.

***

One a side note, the garage I've been using has a very good reputation locally and lots of people I know rely on their services. Having said that, with the knowledge specific to my car that I gained from this forum, I'm starting to notice some little errors in their works on my car; for example the last few jobs I asked I had to do it myself again and got it sorted eventually by myself (with the help of this forum). Perhaps it's time that I look for VAG specialist garage; and there's one fairly local (though there's hardly any info on how good the garage is). I intend to go there for the next MOT and full service to see how they are and talk geek about my car.

[Doctle Odd]

I was wrong again you can get a sump gasket!

[defever]

I was wrong again you can get a sump gasket!

We learn new things every day! But the questions is, is that rubber gasket necessary or will a sump seal much better with silicone gasket? You might know the pragmatic answer to that from your experience and wisdom.

I checked the oil level and its near to the min level so I topped up around 700ml to get it up to the max level again. That's about 1.7L of top up in 4 months (approx 6,000miles).

Given that the leak isn't from the sump gasket, is there anywhere else obvious that I should check?

I'm wondering if there's a hairline crack on the sump...

[grant19841]

Oil filter seal, head cover seal, faulty oil cap, and as you say air line crack perhaps somewhere.

Maybe jack the car up and remove the under tray cover, clear and wipe all oil traces, place some large cardboard on the floor surrounding the engine, run the car for 30min or so and let the engine warm to mid temp then keep a close eye out.
Sometimes oil leaks can go unnoticed because if leaked on hot engine surfaces it will evaporate so check on every journey and monitor the loose.

How's the exhaust fumes, any changes in smell or colour?

Sent from my SM-A300FU using Tapatalk

[zollaf]

max to min is about a litre, so you have lost a fair amount of oil. even a cup full thats leaked out will be obvious. both my audis have a few little leaks. the sump on the s4 is always wet as is the 80, yet neither actually use any oil thats above what you would expect. if you pour a cup of black oil on your drive then you will notice it, if you splash it over the engine you will notice it. if you can't really see much oil on the car and the exhaust pipe isn't dripping with it then its fair to say the engine is probably burning it. a car that is using oil due to a leak generally leave's quite a trace down the road and your drive.

[grant19841]

True, as zollaf said is quite a bit of oil to lose, didn't really think of as he described.

I'd go with engine is burning it too.

Sent from my SM-A300FU using Tapatalk

[Doctle Odd]

Of course if some idiot tried to remove the sump then decided to just put silicone sealant on it to save work it could be leaking into the bell housing. Do you have an undertray? Zollaf may be on the money re burning oil

[zollaf]

be worth pulling the boost pipe off the bottom of the intercooler, see if your lost oil has found a new home down there..

[Doctle Odd]

Is there any oil on the underside?

[defever]

Thanks everyone, I've just had a quick look under the tray...

The sump itself has been bone dry, but the rim is slimy wet. I tried to get a photo on my phone:

2938129382293832938429385

Where the rubber gasket is, you can sort of see the white sealant and I can feel the gasket quite wet all around.

The interesting thing is that anything above it is not slimy, but just gunky from being 16 years old. I can definitely rule out oil filter, oil cooler and head gasket as they are all bone dry.

[zollaf]

yeah, does look like bathroom sealant on the sump, at least i have never found white rtv silicone for cars. i would get that sorted to start with, new gasket properly fitted etc, then see how it goes. maybe the oil was a bit thinner than usual, or a fully syntheti rather than semi. can you get someone to drive behind you with their head out the window to see if they can smell any burning oil.

[defever]

Couple more to note:

This bar on the OS of the sump pan (sorry I don't know what it is) was loose at the bolt (17mm):

29386

So I tightened it. There were couple of sump bolt around it so I guess the garage forgot to tighten it (this is what I meant by the reputable garage making error that I keep spotting)

Also I checked the intake pipes to see if there's any oil residue:

293872938829389

The first two are at the intake manifold. And the third is at the breather valve. I also removed the boost pipe at the intake turbine and its well lubricated.

I think there's quite a lot of oil; or is this acceptable for 16yo car?

And snap... Zollaf, I wasn't quite clever enough to see the bottom of the "S" shape boost pipe!

So I think the sump gasket isn't sealed properly and there's possibly more than usual amount of oil circulating into the intake?

[defever]

Is there any oil on the underside?

Yes, I have the undertray. The tray has been oily and gunky long before I noticed oil leak this year, mainly due to some other fluid leak the car experienced in the past (e.g. brake, coolant, some oil etc.). The noise buffer sponge has absorbed all sorts of fluid so it's quite hard to know any recent residue on it.

Having said this, I can see that the centre bolt that attaches the engine understray and the transmission undertray (the one further back) has been oily and I can see from below that the bottom of the gearbox is fairly. I assume that this is because of the oil leak being sprayed behind from driving.

I never noticed and obvious oil puddle where I park, but then I park on black tarmac road so probably hard to notice...

[defever]

yeah, does look like bathroom sealant on the sump, at least i have never found white rtv silicone for cars. i would get that sorted to start with, new gasket properly fitted etc, then see how it goes. maybe the oil was a bit thinner than usual, or a fully syntheti rather than semi. can you get someone to drive behind you with their head out the window to see if they can smell any burning oil.


Thanks very much Zollaf,

I'm a bit disappointed with the job done. I'll visit VAG specialist independent garage to get it sorted, rather than the one I usually go. Maybe it was a job too specific to do for the generic indy garage so I'll get it sorted at VAG indy with full service and MOT next month.

The oil is in fact full synthetic from ECP. It says on the bottle that it's VW505.00 approved. Should it be semi-synthetic?

Another note, when I replaced the tracking boot, I drove back home with front windows open and I did smell what I thought a exhaust fume. Perhaps it was the burning oil? I don't know, I might be trying to connect the dot in favour of assumptions.

[defever]

So the question now is, assuming that the sump gasket is sorted, how do I deal with the burning oil?

Where from does the oil enter the intake pipes? From oil feed on the turbo or breather valve?

Can something be done about burning oil?

Thanks everyone for very quick and specific responses!

[zollaf]

well the last one i sorted was a passat. that burnt a litre every 1000 miles, probably more. head off, sump off, rods and pistons out, hone bores, new rings, rebuild with new shells and gaskets, went like a train after that, much better. until the owner thought it needed topping up so put a gallon in it when it didn;t need topping up, crazy woman, don't know what she actually broke but it sounded terminal so we found her a golf..

[Doctle Odd]

Can I ask how much labour the charged for when doing the sump?

[zollaf]

probably an hour doc, ooooh, loook at ths, it won't come off, don't worry, bath sealer will sort it...
i would get the sump done and use semi synth oil, run it and monitor the level.. fully can be too thin and leak past the rings...

[Doctle Odd]

I'd say your right Zollaf. As you know by the time you lower the subframe, get it off cleaned properly clean the block etc and reassemble with new oil etc there's not much change out of 4 hours. I did a golf once and the ball snapped off the Allen key on one of the hidden bolts and refused to move. Eventually I decided to remove the gearbox and the bugger fell when I was pulling the box off the dowels. Grrr

[defever]

Can I ask how much labour the charged for when doing the sump?

I can't tell specific to the sump job because I took it in for several jobs: a) steering noise (which I eventually fixed it with new track rod boot), b) coolant leak (which I also fixed it eventually), and c) replace gasket for oil return pipe from turbo.

I think this job with sump gasket put the final nail on the coffin with this garage. I like to believe they are good (very well known locally and lots of people I know use them, too), but the last few visit has been disappointing (came out "fixed" but advised to "monitor and I ended up fixing the problem myself). Of course, without their diagnostics, I wouldn't have found where the faults were. It's unfair for them to complain about about my experiences; perhaps it's all a misunderstanding or I could be one of those very annoying and picky customers who think they know everything and everyone else is in the wrong. Or perhaps they lost interest in cars older than 10 years and all up for super modern cars.

As suggested, I will get the sump sorted, perhaps sooner than next month at the VAG indy and maybe return to them for MOT and full service if they did well.

[defever]

I'd say your right Zollaf. As you know by the time you lower the subframe, get it off cleaned properly clean the block etc and reassemble with new oil etc there's not much change out of 4 hours. I did a golf once and the ball snapped off the Allen key on one of the hidden bolts and refused to move. Eventually I decided to remove the gearbox and the bugger fell when I was pulling the box off the dowels. Grrr

So that sounds like a major job! They might not have had the VAG specific knowledge to complete the job even with a service manual (I hope they have one).

Oh how I wish either of you were in the local area... Thanks all for all your advice and suggestions so far, I'll update you when I get it sorted!

Happy motoring!

[zollaf]

to be fair, if a subframe is in the way on any car for any job, you just drop it. the b5 is dead simple as the steering rack isn't joined to it, so its off with the lower arms and off with the subframe, yes you need alignment pins to put it back, but its only 2 holes at the front that need to line up and some 16mm or so round bar does the same job.

[Doctle Odd]

It's not a difficult job doing the sump just takes a while and when you're getting paid to do it .... I think another garage would be the way to go, even if they never did this job before it's only bolts and you'd see easily how it comes off. You could do it on your driveway if you were insane, with a lift or ramp it's fairly easy, this is a 21 year old design most grease monkeys should have seen it :)

[zollaf]

oh god on the floor it would be awful to do the job. on a ramp its a lot easier...

[defever]

You could do it on your driveway if you were insane

For a second I thought "...may be". But then it was only for a second until my conscience told me NO. I can't do it, I don't have a hoist nor a ramp. I've only just box a tool box to put all my tiny tools so this is way too beyond my capability!

[Doctle Odd]

You can do if on the ground but really you'd need 5 ton high axle stands and an engine support bar or hoist. be as cheap to pay someone as buy those items. Don't worry many blokes have tiny tools, happy wives and several kids!

[defever]

Okay, a little update.

Took it to VAG indy and they had a look this morning. The sump bolts weren't up to spec torque so they've re torqued and it should be fine, they said. They also noticed that there were oil residue all over the gear box, but also said it could just be the old oil spraying from the front and not necessarily a gearbox leak.

To me, what they said matched with what I thought. When I looked underneath yesterday, I noticed that one of the bar on the OS of the sump was not tightened at all (the 17mm bolt just above the sway bar on the pic below):

29391

That bar was in the way of few sump bolts so I assumed that the previous garage forgot to re-assemble it properly, and possibly not done the sump bolts properly either. I also noted the oil residue all over the gearbox which looked like an old oil (black stain).

Interesting thing is that they said oil consumption of 1.5-1.7L in the last 6,000miles is just above usual for VAGs. I'm not too sure what to make of that. If the sump leak was the major cause of oil loss then I'd notice a puddle as Zollaf mentioned but that's not the case and there's obviously some oil in the intake pipes so maybe that's where the majority of lost oil is. I'll check the bottom of the boost pipe when I get it back to see if Zollaf is spot on.

They haven't mentioned much about oil in the intake; they only asked me if it was burning oil and to that I mentioned that I don't smell oil or noticed any excessive smoke (blue nor black), if not any smoke since I cleaned my turbo in March. So I guess that's a good sign that there's no excess oil in the chamber.

£58 something for re-torquing the sump bolts and general inspection. Not bad I think?

I'll try to strike up a geeky conversation and how much I worked on my car when I pick it up later on...

[Doctle Odd]

Not tightening the sump bolts or the little bar that goes to the front mount is very careless at the least and potentially very costly. IME if the engine isn't leaking it doesn't use too much oil, maybe a couple of hundred mils between services. Still you now know the sump is tight, if it's still losing oil then it's not sealed properly and you should get your money back

[mikeybutch]

I might not be the only one who could live with 1.7l over 6k from an engine of this miles if it was steady and any leaks wernt too messy

[defever]

Thanks very much both,

They said the sump bolts were in fact over tightened and the rubber gasket was splurging out, possibly causing an ineffective sealing from the gasket. So they've loosened them and re-tightened to the spec, which is apparently 20Nm. It's only little they agreed, but the rubber does all the sealing work when it moulds with heat. I wonder if the gasket is already deformed from being overtightened since June, but the garage mentioned that there's no leak since they re torqued the bolts.

So I will be keeping my eyes on it. I'll have a look underneath at some point this week and pop the bottom boost pipe to see if there's oil pooling down there.

Mikey, I guess 1.7L over 6km isn't too bad? As you say, the leak isn't messy, there's no puddle on road, no excessive blue smoke, and it's 16yo engine so little bit of incontinence is allowed, I guess. I used to have Rover 200 1.4L that was gushing out oil (needed 1L top up every 2,000 or so!) from the rocker at 60,000miles and never managed to get it sorted until I scrapped it at 120,000miles. Kept the oil clean all the time but it was costly and messy! So compared to that I guess it's much better!

[niall campbell]

you don't say how often you change your oil ?

Changing at 20,000 miles and you will go through more oil over 10,000 miles.

I change mine at 10,000 now after going for the long life service before, its not using as much oil as it used to

[Doctle Odd]

I don't think the AFN engine had a longlife service schedule, it's quite happy running on regular changes with 10w40 semi synthetic oil. 1.7L over 6k is 2.8L lost between services. That's very far from acceptable

[Rob69]

Have a look for a UV dye and light kit, add the dye and drive for a while, then shine the light. might be worth a shot. Kits around a tenner.

[defever]

I had a look underneath this morning; I couldn't tell much difference on the pan, but they've cleaned around it. There's still a thin coat of wet oil but much less than before. I'll see how it goes.

Also checked boost pipes and oil separator on the breather:

293962939729398

(I don't know how to rotate the images, sorry). I checked the s shaped boost pipe under the turbo (not pictured) and that was fine. The hose coming back to trubo from the breather assembly was quite oily and the turbo turbine was also fairly oily.

The pipe pictured is the 90dgree bend pipe going into the intercooler on NS. That was covered in oil and the kitchen towel went black instantly. You were right Zollaf! I also checked the oil separator (new around 1,500miles ago) and that was already catching quite a fair amount of oil and dripping. But I guess that's okay as it'll just drip down to the sump I believe?

So I will keep my eyes out for the next few weeks and see how it behaves. I have MOT next month and will have full service as well so it'll be interesting how much oil I lose then.

[defever]

you don't say how often you change your oil ?

Hello Niall, I usually do it 6,000-8,000miles or 6months, which ever comes first. I have full service with MOT every year and do the interim oil change by myself in between. I've been using Triple QX oil 5W-40 full synthetic (VW 505.00 approved) from ECP, but I'll change it to Castrol next time.


Iit's quite happy running on regular changes with 10w40 semi synthetic oil.

Thanks Doctle, I always thought it needed 5W-40 full synthetic, but I'll ask what the garage will put on the next service (next month). Castrol oil check link recommends 5W-30 full synthetic Edge or Magnatec. I'll do a little homework on how different 5W-30 and 10W-40 full / semi are. I should know what the numbers mean but I haven't really paid attention other than what the oil checker says for my engine.


Have a look for a UV dye and light kit, add the dye and drive for a while, then shine the light. might be worth a shot. Kits around a tenner.

Thanks Rob, if there's still leak, then this is my next step. I've seen few YouTube clips on this and it seems quite useful.

Thanks very much everyone!

[defever]

New year update on this!

I checked the sump this morning, in preparation for MOT & Full service on Monday. Last year, no. 3 glow plug was stuck and couldn't be replaced so I gave a blast of penetrating oil on all four plugs to help the mechanic out.

So, under the engine, the sump is dry! Around the rim is still moist, but no way near as moist as it was before this garage re-torqued the bolts. So I'm quite happy with it. Thank you VAG specialist garage.

However, I'm still noticing slight decrease in oil level. I looked around and I noticed that the intercooler pipe (the right angle pipe going into the cooler on the nearside) was dripping with oil! I took it out, wiped the pipe, jubilee clips and the interface.

Maybe I need to replace the pipe, as it's rubber and probably hasn't been replaced since factory. But that will not resolve the fact that there's oil passing through the intake.

My next question is: What can I do to minimise oil being transported through the intake and inter-cooler?

Is this inevitable for 16yo TDi?