Audi A6 - High mileage VW/Audi TDi engines

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Fri 29 Oct 2010 13:24
Audi A6 - High mileage VW/Audi TDi engines - Trilogy

I've taken my 1998 Skoda Octavia 90bhp to just over 200,000 with very few problems. I'm looking to buy a prePD or PD engine A6 which has covered around 130,000 miles and run it to over 200,000 miles.

Has anyone else any experience of doing this and were there any problems?

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Fri 29 Oct 2010 13:53
Audi A6 - High mileage VW/Audi TDi engines - 659FBE

VAG diesels will run to starship mileages if you buy the right one and maintain it properly. Doing both of these things is not as easy as it might seem.

The pre-PD diesels were reliable but are all getting too old now. The economy was excellent but they lack the power of the PD units.

The best PD units are mid-period 1.9s with solenoid injectors. Avoid the later piezo injector engines and avoid the 2.0 PD at all costs because of the likelihood of oil pump drive failure - especially in N-S installations. The earliest PD engines had a rather complex and flaky fuel cooling system which is also better avoided.

The best vintage PD is probably an '04 1.9 130 (AWX) - the 150 HP units are not as reliable and don't actually go much better.

All PD engines require oil to VAG spec. 505.01 (fixed servicing) or 507.00 (variable). Camshaft wear will be the result of variations from this spec. - although the fully-synth 507.00 is fine for both, but a little more expensive. There is a general consensus, which I share, that variable servicing is not good for engine wear unless operated under the most favourable conditions - which few are.

I change the 507.00 oil in my AWX every 7k miles. So far, very good.

The latest CR engines run very nicely and are smoother than the PDs (but without the "shove") but I am beginning to hear of far too many (piezo again) injector failures and HP pump failures. Best avoided for now unless under warranty. The beauty of the PD system is that the highly stressed pump plunger followers are oil rather than fuel lubricated. It makes a considerable difference.

659.

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Fri 29 Oct 2010 16:09
Audi A6 - High mileage VW/Audi TDi engines - Trilogy

Thanks 659,

I can't really afford a c.04 A6 so might go for a 03/04 Passat 130 pd tdi. How do I know which ones have solenoid and which piezo? I'm also going to look at a pre PD 115bhp A6 Avant, fsh with 130,000 miles. Probably its best I drive a Passat PD and the older A6 to see which I prefer.

Even though the prePD is older, as it's simpler is likely to be more reliable and be better to a higher mileage?

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Fri 29 Oct 2010 16:51
Audi A6 - High mileage VW/Audi TDi engines - 659FBE

An '03/4 Passat 130 would be a good choice - right fuel system with solenoid injectors. I'm not sure when they changed but it was later - probably '05/6.

Once you've driven a PD engined vehicle, you would not be happy with a vehicle of similar weight but fitted with the earlier engine - it just doesn't have the grunt.

I would favour the (right) PD engine in terms of reliability over the earlier engines with rotary (VE) pumps. The PD system is in essence very simple but needs careful maintenance in terms of timing drive replacement and the use of the correct engine oil. Do this, and they last very well.

If you're in the market for a saloon, have you looked at the old Skoda Superb (nee Passat)? They all have PD engines (the 4 cyl diesels) and offer more legroom and better equipment per unit cost than the Passat. Mine goes well - but there was a narrow window in time between getting folding rear seats and the 1.9 AWX (rather than the hopeless 2.0) engine - so if you want one of those you'll have to look.

I did, and I'm pleased with it.

659.

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Fri 29 Oct 2010 18:17
Audi A6 - High mileage VW/Audi TDi engines - concrete

Hello 659, I have a 55 Skoda Superb with a 130PD 1.9 diesel engine, coming up 5 years old with 110K on the clock. I have always been on the variable service regime with my local Skoda dealer. It seems to ask for service approx every 17K or so. They use the fully synthetic oil and that is what I top up with occasionally. I am very happy with the dealer and the car runs like a sewing machine. They tell me they service many cars with extremely high mileages, which is encouraging. My mileage is 90% motorway at about 2 to 2.5K revs returning over 50mpg. I never do short journeys and keep tyre pressures right. I am hoping to run the car until it drops, hopefully at least 3 more years until I retire. By then it should have about 200K on the clock. Some of your comments were encouraging, some worrying. Do you think I can improve my chances of keeping the car running by doing anything differently? I am so happy with this car, I am able to transport 3 6'5' 125Kg rugby players plus my not inconsiderable frame in extreme comfort with legroom to spare. Not many cars in this price range, or above, can do that with ease. Your comment would be appreciated. All the best. Concrete

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Fri 29 Oct 2010 20:22
Audi A6 - High mileage VW/Audi TDi engines - 659FBE

Greetings, Concrete. I would say your Superb is one of the few which is suited to the VAG variable servicing regimen - so carry on as long as you use and top up with VAG spec 507.00 oil.

These cars will run to starship mileages but make sure the plenum chamber drain bungs are removed and that the outer pollen filter holder seal is replaced with mastic strip as per the VW branded TSB. Failure to do this will result in costly rainwater ingress.

You could also consider removing the upper suspension ball joints' pinch bolts and greasing them thoroughly before they rust in and become a problem. These cars will usually outrun a set of front suspension arms and the consequences of rusted bolts here are very high labour costs. Removing and greasing the bolts takes 10 mins per side if they are not stuck.

The 1.9 AWX is a peach of an engine in terms of performance and economy - but not the smoothest. In a big chassis like the Superb with high gearing, it's OK and makes a great motorway cruiser. I got a genuine (not trip computed) 53 mpg on my last run from London to Birmingham with the cruise set at 76 (indicated) mph. The car was fully loaded one way.

Not many vehicles can match this with the advantages of genuine legroom and low first cost.

659.

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Fri 5 Nov 2010 15:59
Audi A6 - High mileage VW/Audi TDi engines - concrete

Hello 659FBE, sorry I am late in replying, I have been working in Scotland for the past week or so. Thanks for the re-assurance and the useful information. The car is going into my local Skoda dealer for an MOT in 2 weeks and I will mention your suggestions and get a quote from them. So far they have been very good and their labour rates are very fair. Also if they do it you can bank some goodwill for the future, this has already proved the case after 5 years of steady service and repairs they have performed small operations free of charge, which is quite nice. I agree the 1.9PD 130 does sound like a bag of hammers at tickover but once on the move it is great to drive. The worst sound is the fan on the climate control unit, I was told 2 years ago it sounded like it was on the way out but it is still whiring away although quite loud when stood at lights etc. I expect the fan will pack in one day but 5 years of service is not bad. I have thought of replacing the car but cannot justify the money and possibly end up with an inferior car so roll on 'starship' mileage, to boldly go where no car has been before!! Regards Concrete.

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Tue 16 Nov 2010 13:34
Audi A6 - High mileage VW/Audi TDi engines - craig-pd130

I hope you don't need the upper ball joint doing: budget around £450 - £500 per side if it does.

It's one of those jobs that's worth having a VW / Audi dealer quote you on: when my Passat B5.5 needed it doing, the main dealer's price for the job was actually cheaper than a local trusted independent.

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Fri 29 Oct 2010 20:53
Audi A6 - High mileage VW/Audi TDi engines - dieselnut

' I'm also going to look at a pre PD 115bhp A6 Avant, fsh with 130,000 miles. '

If its 115 bhp it will be a PD engine, should have 85Kw on the printed sheet in the service book or spare wheel well.

The PD engines came in 100, 115, 130 & 150bhp .

The pre PD engine was 110bhp.

The 115 may be a bit underpowered in such a big car but a test drive will resolve the question for you.

It can of course be chipped to 150 or thereabouts.

Deffinately hold out for the PD engine, as 659 says, it is a peach.

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Sat 30 Oct 2010 00:02
Audi A6 - High mileage VW/Audi TDi engines - Trilogy

Hi dieselnut,

It's an 'X' plate pre-facelift. I didn't realise the PD engine came in before the facelift model.

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Sat 30 Oct 2010 00:17
Audi A6 - High mileage VW/Audi TDi engines - Trilogy

BTW if it is a PD it will be an early one and 659 cautioned against buying one of this age.

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Sat 30 Oct 2010 01:13
Audi A6 - High mileage VW/Audi TDi engines - dieselnut

My son had an X reg Passat & that had the 115 PD engine & was the best of the 4 Passat's the family have owned.

This engine will have the slightly dubious fuel cooling system so possibly not the best choice, but if that is your budget it is at least a PD engine.

You will of course get better value for money with a Passat or Skoda.

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Sat 30 Oct 2010 10:33
Audi A6 - High mileage VW/Audi TDi engines - Trilogy

Thanks,

Is the fuel cooling system expensive to replace on the earlier PD engines if it goes wrong?

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Sat 30 Oct 2010 11:57
Audi A6 - High mileage VW/Audi TDi engines - dieselnut

I don't know about cost, we never had a problem with ours.

There is a small heat exchanger so would imagine no change out of at least £250 plus an hour or so labour.

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Wed 17 Nov 2010 23:53
Audi A6 - High mileage VW/Audi TDi engines - Avant

"As an example, I find the PD in my Superb to be entirely acceptable except when worked hard (but it does "growl" nicely) but I find the noise of the diesel M-B B Class vehicles to be unacceptable - inside and out. It might be just me."

I'm sure it isn't, 659 - I had a B200CDI for 18 months or so before i could stand it no longer: it's even worse coupled, as mine was, to a CVT. The PD Golf estate that followed it was much quieter, and the current CR diesel Octavia even quieter - although I accept that there are more things to go wrong, if I keep it too long, than on the 1.9 PD that has served you and others so well.

Many thanks for sharing your experience and ex[ertise with us, 659 - much appreciated (was 659 FBE your first car number perhaps? Lincolnshire registration I think).

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Thu 18 Nov 2010 18:25
Audi A6 - High mileage VW/Audi TDi engines - 659FBE

Thanks for your kind words. 659 FBE was a much loved ancient Morris Minor - fixable by the road side with agricultural tools. Not much chance of that with the engines presently under discussion. Car design has progressed however...

N.E. Lincolnshire was indeed its home.

659.

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Fri 19 Nov 2010 10:38
Audi A6 - High mileage VW/Audi TDi engines - dieseldogg

i think? my father mentioned catching on sommat & bending a half-shaft in a Singer car, pulling it at the roadside and straightening it with a hammer/wee sledge over a kerbstone/big stone, before proceeding .

Changed times indeed.

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Sun 5 Dec 2010 20:35
Audi A6 - High mileage VW/Audi TDi engines - dieseldogg

Why does there appear to be a 4th Dec reply to this thread, i cannot find it,(if there is one?) what am I misunderinstanding?

Cheers

M

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Sun 5 Dec 2010 22:53
Audi A6 - High mileage VW/Audi TDi engines - 659FBE

I was hoping for a further input too - perhaps from someone who had experienced piezo injector failure on the road.

Vehicle type, misfire or dead stop?

659.

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Sun 5 Dec 2010 23:41
Audi A6 - High mileage VW/Audi TDi engines - Avant

"Why does there appear to be a 4th Dec reply to this thread, i cannot find it,(if there is one?) what am I misunderinstanding."

About 4 posts up from yours: it was presumably answering a post above it.

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Mon 6 Dec 2010 19:43
Audi A6 - High mileage VW/Audi TDi engines - dieseldogg

Erm, Avant,

Explain how the calender on this forum works again?

or is there a secret Pope among the moderating staff?

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Mon 6 Dec 2010 22:12
Audi A6 - High mileage VW/Audi TDi engines - Avant

"Explain how the calendar on this forum works again?"

It isn't anything complicated: if you reply to a particular post instead of the first post, your post may show immediately underneath unless someone has replied to it anyway.

As an example, mine has just appeared immediatety below yours.

Edited by Avant on 06/12/2010 at 22:13

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Tue 7 Dec 2010 19:28
Audi A6 - High mileage VW/Audi TDi engines - dieseldogg

Ah?

Do I now understand

Let us see

?

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Mon 6 Dec 2010 20:33
Audi A6 - High mileage VW/Audi TDi engines - SteveLee

There was a new comment by Greengrocer2 about 5 posts back, new posts do not necessarily appear at the bottom if they are an embedded reply.

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Mon 6 Dec 2010 21:36
Audi A6 - High mileage VW/Audi TDi engines - dieseldogg

Embedded???

Do you mean an edited earlier post?

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Tue 7 Dec 2010 19:30
Audi A6 - High mileage VW/Audi TDi engines - dieseldogg

OK Now I see

I did not realize that one could reply to any other than the absolute last post so therefore wrongly understood that it would be strictly chronological.

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Sat 29 Jan 2011 01:35
Audi A6 - High mileage VW/Audi TDi engines - rogue-trooper

In 2004 I bought a 1996 A4 110tdi with 59k miles. I had to change for something bigger in 2007 and it had 90k miles on. I sold to my wife's uncle who has had no problems at all since and it now has about 160k on it.

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