ChrisP

All sorted! I removed both circular ‘hatches’ at rear of xenon headlamps to access the back of both bulbs, to which I eventually applied enough anti-clockwise twist, bayonet-style. I then simultaneously ‘ventilated’ the interior of the headlamp, with the Audi’s own 12v tyre pump tube inserted through one aperture, and using the other as exhaust, whilst applying a hair dryer to the exterior of the front lens. I kept the hair dryer moving, and continuously checked the lens temperature with my spare hand. Two 20’ sessions on consecutive days were required to clear some pretty heavy condensation. Hurrah!

Brill, thanks so much. Chris

Hi again everyone, After all the wet weather and a couple of high pressure spray car-washes recently, I have developed quite a bit of condensation in my nearside headlamp of my 2015 C7 A6 Allroad. This subject has had a lot of cover over the years and I've looked at what my searches have thrown up. After checking for cracks in the lens, and found none, I've tried covering the external lens with aluminium foil and switching on full-beam for 2-30 minutes, with only marginal benefit, and next I'm going to try a couple of applications of hair-dryer treatment on medium heat settings. Responses to previous posts suggest that this may help, but that residual water vapour predictably condenses as the unit cools, so the approach maybe more effective in the summertime, and will certainly require several attempts. I gather from Gareth's response to an enquiry about condensation in a Q7's Matrix LED Headlight lens in the last year or two that these are sealed units and that not much else can be done. However, mine are 2015 Xenons. I wonder whether this might provide any additional opportunity for sorting the problem? I note that removing the headlamp unit sounds one hell of a hassle on the C7, as is even changing the bulb. I don't live in much hope. Chris

Hi again everyone, After all the wet weather and a couple of high pressure spray car-washes recently, I have developed quite a bit of condensation in my nearside headlamp of my 2015 C7 A6 Allroad. This subject has had a lot of cover over the years and I've looked at what my searches have thrown up. After checking for cracks in the lens, and found none, I've tried covering the external lens with aluminium foil and switching on full-beam for 2-30 minutes, with only marginal benefit, and next I'm going to try a couple of applications of hair-dryer treatment on medium heat settings. Responses to previous posts suggest that this may help, but that residual water vapour predictably condenses as the unit cools, so the approach maybe more effective in the summertime, and will certainly require several attempts. I gather from Gareth's response to an enquiry about condensation in a Q7's Matrix LED Headlight lens in the last year or two that these are sealed units and that not much else can be done. However, mine are 2015 Xenons. I wonder whether this might provide any additional opportunity for sorting the problem? I note that removing the headlamp unit sounds one hell of a hassle on the C7, as is even changing the bulb. I don't live in much hope. Chris

Thanks Gareth, I'll call one tomorrow. Ironically, it actually came loose following the attentions of a large bodyshop, the kind that your insurer says you have to use to get the courtesy car entitled by your policy, and where you only get to speak to manager after making a complaint. Chris

Hi Y'All, I believe that the OEM Audi Allroad plastic rear 'wheel flare' trim extension replacements come new with strips of double-sided sponge rubber adhesive mounting tape in situ, and all one has to do is pull the protective strip off the adhesive surface of the tape to affix. However, I want to reuse and replace the piece of trim that came off, so have carefully and thoroughly cleaned it up, along with the exterior painted bodywork around the wheel-arch, to eliminate all traces of old tape, oil and wax etc, culminating in a methylated spirits (alcohol) rub or two. But what should I use adhesive-wise to reattach the trim securely? I don't want it falling off and any hazard aside, the OEM article costs £150 on eBay. 3M do a 2cm wide, double sided, 0.7-0.8mm thick, sponge rubber, mounting tape, apparently designed for this purpose but the reviews appear mixed (eg 'useless'). Casting the net wider using Google & YouTube etc, into the world beyond Audi, self anointed pundits suggest everything from 'No More Nails', to JD Weld vulcanised silicone rubber sealant adhesive, to a drop or two of Superglue applied to the failed adhesive surface of the original sponge rubber mounting strip -advice which for me came too late. For the plastic wheel flare trim itself to stay in place, the adhesive will need to be strong enough to hold it under tension. This is because for the trim follow the contours of the car's hind-quarter, it essentially needs bending into place, and since the silicone, for example, needs 24hrs to cure to full strength, it would clearly need the use of some plastic clamps to temporarily hold it in place. I can imagine making a dreadful mess with the silicone sealant, or the tape-mounted wheel arch flare falling off on the M5. Has anyone been here before? All advice gratefully received. Thanks, Chris

Hi Steve, Yes, I was going to look at the Audi Extended Warranty, and the their service plan, given the car's relative youth, mileage-wise & condition. Thanks, Chris

Hi Jason, Thanks. Neither injectors, bolts or seals injectors were touched or serviced before they first blew, or started to leak, and in the case of those that blew out, the steel retaining bolts stripped their retaining sockets in the Alu head/block, thus then requiring helicoil fixation. Initially, two bolts were unfortunately reused, but when I read around the subject and appreciated the implications, I had the garage replace with new and retorque to spec, and this approach was subsequently used for all the others. New copper seals were used on each occasion throughout. So we still have no explanation for so many injectors coming loose and requiring resetting. Hi Gareth, Thank you. The engine has been serviced to manufacture's spec, with regular oil changes until this last twelve months, since when the same has been achieved by continuous topping up necessitated by the leaks (-in course of trying to fix which one cracked rocker cover has been replaced, and a front crank-shaft seal three times, latterly using the Victor Reinz (disposable) special setting tool). In respect of your suggestion re worn piston rings, as the likely cause of raised crank-case pressure, there is no dipstick on these vehicles to investigate in the way you recommend, simply the bayonet-fit top-up cap. And as I mentioned, there is no apparent loss of power or fuel economy, and the engine-running seems entirely smooth, the tachometer showing no rpm hunting.or dancing about. However, my reading of the Rheinmetall website this pm (https://www.ms-motorservice.com/int/en/technipedia/sealing-problems-and-piston-ring-damage-889) does suggest that an injector leak may cause diesel deposition on rings and cylinder walls, displacing lubricant and rapidly accelerating their wear. This begs the question (-as to why so many injectors should be thrown) which I posed to Jason...

Thank you. Apologies for lack of clarity. I guess what I'm seeking are answers to the following questions: (1) why the car should have thrown 6 diesel injectors (#6 now puffing too!) / 130,000 miles (2) whether these injector problems may have somehow resulted in raised crank-case pressure, in the absence of either (a) cardinal signs of piston ring damage (ie irregular running, loss of power and poor fuel economy) or (b) evidence of PCV blocking, either of which are frequently cited as the 'usual causes'. And if the injector problems can be indicted as a cause of raised crank-case pressure, how might this occur? What is the physics? The Audi specialist was unwilling to countenance the notion that so many oil leaks and such heavy lower engine compartment oil contamination were mere coincidence. He took the view that they could not have occurred without underlying predisposing cause (- ie raised crank-case pressure). Thanks, Chris

Hi Y'All, I initially posted this yesterday as a follow-up to my original Adblue issues, whereas the help I need relates to a different problem, namely recurrent oil and coolant leaks. I've therefore belatedly reposted it here. Apologies. Since 2018, I've had a 2015 post-facelift A6 C7 3.0L TDI V6 Allroad which I've taken from 40K to 130K miles, initially with main dealer support, and latterly that of the village garage. Having just had had some Adblue system faults expensively fixed (-new NOx sensor in the villlage, and then a Adblue pump new pump and ECU reflash by a main dealer), I'd now quite like to unload it, However, it has some very obvious oil and coolant leaks, presently unsorted, for which I'll naturally take a hit price-wise. These include leaks from around the sump's retaining bolts, ongoing leakage from the front crankshaft seal (-replaced x2 this last year), as well as oil and coolant into the 'V' from the cylinder head gaskets. Having had these issues looked at by an independent 'Audi Specialist', they feel sure that problems of this extent speak to underlying raised crank-case pressure as a cause. The specialist was also surprised by the vehicle's history of having blown no less than 5/6 diesel injectors over the last couple of years (-each requiring reseating with new retaining bolts and seals, several of the retaining bolts' cylinder-head sockets having needed to be heli-coiled in addition). In fact they say they cannot recall another 3.0L V6 TDi in any VAG vehicle which has thrown so many. But what amazed them more was how smoothly the car runs and, in respect of poke and economy, I cannot fault it myself either. For the record, I've never let the oil level drop much, having always acted promptly on the instrument console advisories. Potential causes of raised crank-case pressure obviously include include leaking piston rings and crank-case vent problems. However, I cannot believe, given the above feel-good stuff, that the underlying issue is leaking piston rings. Furthermore, in respect of blocked crank-case venting, I had one oil-leaking cracked (plastic) rocker cover replaced last year, and the other, and its integral PCV, rechecked and declared OK just last month. Reading round the subject of raised crank-case pressure in the VAG 3.0L V6 TDI on line, I'm afraid I've drawn a blank in respect of this being a common or inevitable problem, even in higher mileage vehicles. Any ideas as to its likely underlying cause would therefore be gratefully received. The Audi Specialist indicted the blow-back around the car's previously loose diesel injectors, but I didn't entirely follow the physics. Needing another A6 Allroad I can rely on, I've just bought an immaculate (2018) A6 C7 3.0L V6 TDI, with just 26K on the clock and I'd like to do everything possible to mitigate the risk that it too might also suffer such problems as it ages. I'm also inclined to take out an AUDI service plan and extended warranty to manage the unexpected. All insights gratefully received. Thank you.

Thank you, Chris

Hi Y'All, This is by way of part follow-up to my last 'C7 vs C8 Audi A6 Allroad purchase?' posting, and an appeal for some info as to the likely causes of raised crank-case pressure in my old soon-to-be-disposed-of 2015 218HP C7. After having the 130,000 mile 'AdBlue System Fault' advisory confirmed as a faulty (low pressure) AdBlue pump at an Audi Main Dealer, who proceeded to replace the pump and reflash the ECU software, thus sorting the problem satisfactorily, I took the car to a well-thought-of 'Audi Specialist' about 10 miles away to look over a chronic recalcitrant oil leak that the local heart-sunk village garage had failed to sort, despite replacing a cracked (plastic) offside rocker cover, and having twice refitted the front crankshaft seal over the last twelve months. They are a great outfit who previously kept my pair of mid-1990's BMW 525iX's on the road for the last 7-8 years of their lives. The independent specialist confirmed multiple high-volume oil leaks, including the front crankshaft seal (again), around individual bolts attaching the sump, and at the head gaskets on both sides, where also leaking coolant. They diagnosed (-by implication) an underlying elevated crank-case pressure, felt the necessary repairs uneconomic, and recommended that the said sad machine be released into the trade through one of the discounted online high volume purchasers, caveatemptor.com, and that I clench my teeth and take the hit. Two things amazed them: (1) the car drove very well, the engine remarkably smooth and responsive (-confirming my own impression of great poke and economy) and (2) its history of having thrown no less than 5/6 of its diesel injectors over this last four years, each having required new retaining bolts, seals and helicoils in the Alu head. Never had they seen such a thing in any 3.0TDI-engined context previously. They attempted to explain the raised crank-case pressure with reference to the thrown injectors, and their gunk-blocked by-pass channels, but I failed to grasp the physics. In the meantime, my needing a replacement Allroad, I bought a 2018, 26,000-mile C7 A6 3.0L TDI, with tech-pack and a few more (ie 268) HP, freshly serviced with a 12-month MOT. Looking ahead, I remain fearful. How might I avoid or mitigate the same (unknown!) predisposing problem in the new motor? Famous causes of pathologically raised crank-case pressure include disrupted piston rings, and blocked/choked PCV's. However, with so smooth a free-revving and pokey engine, and great fuel economy, surely the rings could not be broke? And looking into the PCV issue, in the 3.0L TDIs, the PCV function is apparently integrated into the plastic rocker-cover, one of which was replaced for a crack, (-originally suspected as the cause of the oil leak), some 12 months back, and the other declared patently innocent just last month. Help me understand, please! Than you, Chris

Some advice please, guys n gals, I have owned a 2015 C7 AUDI A6 3.0TDI 215bhp Allroad since 2018, and have taken it from 40 K to 130K initially with main dealer servicing, and latterly the village garage (-who had previously looked after a couple of my BMW 525iX's very well). Things started going downhill, since when it has felt that the car has owned me, just over a year ago when the Audi 'threw' a diesel injector. Both that injector, and another found leaking on inspection, were cleaned and reseated, and their stripped retaining bolts' sockets heli-coiled back into the cylinder head (-and new bolts used at my insistence, given the torque-tech issue). The same problem had occurred with another injector two years before -an unsettling, but in the event, a durable repair. However, on the latter occasion, a smell of diesel persisted, about which the garage said they weren't surprised and reassured me, citing heavy prior cylinder head diesel contamination. MPG was satisfactory on a 140-mile test drive, to Bristol and back, and I set out on a trip from Worcestershire to Scotland to see a newborn granddaughter. Just short of Tebay, the steering suddenly became oddly uncertain, traffic density was thankfully low and, in drizzle at dusk, I slowed to 40mph without braking on a serendipitous stretch of uphill gradient, and gently eased the vehicle into the nearside lane, whereupon it suddenly spun anticlockwise thro 180º and then, pointing south, slammed its offside into a nearside crash-barrier along the hard shoulder, incurring modest damage to front and rear offside wings. No other vehicle was involved. Highways Agency recovered me to some nearby off M-way services, the police remarking on a strong smell of diesel, as well as noticing diesel on the road under the car. The Highways Agency recovery man complained that the diesel transferred to the soles of his boots lubricated them on the rubber pedals of his truck. I called the AA, to diagnose the source of my diesel leak, my hoping that were this identified and fixed, then I might be able to drive the vehicle home, safely. The insurers' flatbed truck was otherwise going to take 48-72hours. The AA identified a loose (ie completely detached) low-pressure diesel return pipe as the source, then left the scene saying they shouldn't have attended a vehicle involved in an RTA. Left to my own devices, I reattached the diesel return, using a cable tie to secure it. After testing the steering on a few circuits of the now deserted services' parking lot, tyres dry and diesel dissipated, I gingerly headed back down an empty M6 at a sedate 50mph, my arriving uneventfully home at daybreak. A new OEM diesel return system was duly fitted and the bodywork repaired by the insurers. And then another injector reseated. The body-shop remarked upon an engine oil leak, for which a cracked offside rocker-cover was blamed and replaced. However, the oil leak persisted, and the garage fingered a leaking front crankshaft seal. They stripped off the front of the car for access, removed the pulley, replaced the seal and then put everything back together again. About 50 miles later, the Audi invited me to top-up the engine with a litre of oil... Pulling off the M5, I could see the front crankshaft seal dripping again. Reading about the subject, I noted that a £75 Audi special tool was recommended for the seal replacement job, as well as the use of some high-temperature superglue at £40/tube. I sourced a Victor Reinz OEM seal, which was handily supplied with a bespoke plastic disposable fixing tool in the box, and ordered the expensive special glue. The Seal was replaced a second time by the village garage and, at my instigation, the rocker cover CCV apparatus on the nearside bank checked for blockages. Before I could replace the car, an AdBlue System Fault advisory appeared on the instrument console with '650miles to no restart'. Diagnostics indicated an intermittent NOx sensor fault. Replacement corrected the NOx sensor diagnosis, but the AdBlue System Fault notice persisted, along with an illuminated orange engine light, further diagnostics indicating an ostensibly new 'low reductant pump pressure' fault. The AdBlue injector nozzle appeared 'as clean as a whistle'. Time for a visit to the main dealer. They confirmed the 'low reductant pressure' error, and whilst discovering that the Adblue pump is physically working, with measurable output, they suspect a defective pressure sensor, an integral part of the pump and have recommended pump replacement (£800 + Labour @ £169/hr + VAT). Inspection also leads them to suspect an ongoing oil leak, as well as a mysterious coolant leak (-pink liquid was identified in the engine 'V' as well as dripping beneath the car, where admixed with oil, it besmirched their workshop floor). Coolant level in the expansion/top-up tank was satisfactory. Another injector was leaking, btw. Divers other sundry issues were identified. They appeared quite shocked; I was sad. When I have had the AdBlue pump replaced, the ECU reset, the question of the oil and coolant leaks sorted, and the injector reseated, it will be time to dispose of the vehicle and buy a younger model. For various reasons, I genuinely need an A6 Allroad, so the choice lies between another slightly later (eg 2018) low mileage (eg 30K) C7, or a somewhat higher mileage C8, my planning to spend £25-30K. Fortunately, I do not need to sell the good sense of this to a significant other. So here's the question: how much of this tale of woe is down to recognised age-related C7-specific problems which I might avoid with a C8? Or might a leap into an even more technologically complex' C8, whilst avoiding groundhog-day, be a frying pan-fire job? Either way, I'm thinking entry-level, not biturbo. Obviously enough, I'm posting this in both the C7 and C8 forums. I look forward to folks' opinions and considered advice. Thank you, Chris Poole

Some advice please, guys n gals, I have owned a 2015 C7 AUDI A6 3.0TDI 215bhp Allroad since 2018, and have taken it from 40 K to 130K initially with main dealer servicing, and latterly the village garage (-who had previously looked after a couple of my BMW 525iX's very well). Things started going downhill, since when it has felt that the car has owned me, just over a year ago when the Audi 'threw' a diesel injector. Both that injector, and another found leaking on inspection, were cleaned and reseated, and their stripped retaining bolts' sockets heli-coiled back into the cylinder head (-and new bolts used at my insistence, given the torque-tech issue). The same problem had occurred with another injector two years before -an unsettling, but in the event, a durable repair. However, on the latter occasion, a smell of diesel persisted, about which the garage said they weren't surprised and reassured me, citing heavy prior cylinder head diesel contamination. MPG was satisfactory on a 140-mile test drive, to Bristol and back, and I set out on a trip from Worcestershire to Scotland to see a newborn granddaughter. Just short of Tebay, the steering suddenly became oddly uncertain, traffic density was thankfully low and, in drizzle at dusk, I slowed to 40mph without braking on a serendipitous stretch of uphill gradient, and gently eased the vehicle into the nearside lane, whereupon it suddenly spun anticlockwise thro 180º and then, pointing south, slammed its offside into a nearside crash-barrier along the hard shoulder, incurring modest damage to front and rear offside wings. No other vehicle was involved. Highways Agency recovered me to some nearby off M-way services, the police remarking on a strong smell of diesel, as well as noticing diesel on the road under the car. The Highways Agency recovery man complained that the diesel transferred to the soles of his boots lubricated them on the rubber pedals of his truck. I called the AA, to diagnose the source of my diesel leak, my hoping that were this identified and fixed, then I might be able to drive the vehicle home. The insurers' flatbed truck was otherwise going to take 48-72hours. The AA identified a loose (ie completely detached) low-pressure diesel return pipe as the source, then left the scene saying they shouldn't have attended a vehicle involved in an RTA. Left to my own devices, I reattached the diesel return, using a cable tie to secure it. After testing the steering on a few circuits of the now deserted services' parking lot, I gingerly headed back down an empty M6 at a sedate 50mph, my arriving uneventfully home at daybreak. A new OEM diesel return system was duly fitted and the bodywork repaired by the insurers. And then another injector reseated. The body-shop remarked upon an engine oil leak, for which a cracked offside rocker-cover was blamed and replaced. However, the oil leak persisted, and the garage fingered a leaking front crankshaft seal. They stripped off the front of the car for access, removed the pulley, replaced the seal and then put everything back together again. About 50 miles later, the Audi invited me to top-up the engine with a litre of oil... Pulling off the M5, I could see the front crankshaft seal dripping again. Reading about the subject, I noted that a £75 Audi special tool was recommended for the seal replacement job, as well as the use of some high-temperature superglue at £40/tube. I sourced a Victor Reinz OEM seal, which was handily supplied with a bespoke plastic disposable fixing tool in the box, and ordered the expensive special glue. The Seal was replaced a second time by the village garage and, at my instigation, the rocker cover CCV apparatus on the nearside bank checked for blockages. Before I could replace the car, an AdBlue System Fault advisory appeared on the instrument console with '650miles to no restart'. Diagnostics indicated an intermittent NOx sensor fault. Replacement corrected the NOx sensor diagnosis, but the AdBlue System Fault notice persisted, along with an illuminated orange engine light, further diagnostics indicating an ostensibly new 'low reductant pump pressure' fault. The AdBlue injector nozzle appeared 'as clean as a whistle'. Time for a visit to the main dealer. They confirmed the 'low reductant pressure' error, and whilst discovering that the Adblue pump is physically working, with measurable output, they suspect a defective pressure sensor, an integral part of the pump and have recommended pump replacement (£800 + Labour @ £169/hr + VAT). Inspection also leads them to suspect an ongoing oil leak, as well as a mysterious coolant leak (-pink liquid was identified in the engine 'V' as well as dripping beneath the car, where admixed with oil, it besmirched their workshop floor). Coolant level in the expansion/top-up tank was satisfactory. Another injector was leaking, btw. Divers other sundry issues were identified. They appeared quite shocked; I was sad. When I have had the AdBlue pump replaced, the ECU reset, the question of the oil and coolant leaks sorted, and the injector reseated, it will be time to dispose of the vehicle and buy a younger model. For various reasons, I genuinely need an A6 Allroad, so the choice lies between another slightly later (eg 2018) low mileage (eg 30K) C7, or a somewhat higher mileage C8, my planning to spend £25-30K. Fortunately, I do not need to sell the good sense of this to a significant other. So here's the question: how much of this tale of woe is down to recognised age-related C7-specific problems which I might avoid with a C8? Or might a leap into an even more technologically complex' C8, whilst avoiding groundhog-day, be a frying pan-fire job? Either way, I'm thinking entry level, not biturbo. Obviously enough, I'm posting this in both the C7 and C8 forums. I look forward to folks' opinions and considered advice. Thank you, Chris Poole