High miles for an AHU?

[DRP67207]

Hello all.

I am wondering what qualifies as "high miles" on the AHU TDIs.  Obviously the maintenance schedule throughout it's life can swing this figure one way or another, but at what point do internal bits typically start wearing out, requiring rering/rebuild, that kind of thing?

I am looking for a donor to swap into my '81 caddy and run M, and ideally would like to be able to just replace some seals, new belts, and drop it in and be able to run it for a fair bit before it needs major attention.  Is there a mileage cutoff I should try to stay under to avoid major overhauls in the very near future, or is it simply too dependent on the care and driving of the previous owners?  There seem to be a lot around in the low 200K rang. Is this pushing it, or do these still have a fair amount of life left?  Does a little smoke indicate more serious wear than on the IDI's where a little smoking on start up is pretty normal?  Wondering what to look for...

Sorry for the ignorance, I'm new to the TDI's and appreciate any insight you all might be able to offer.  Thank you.

[Renax]

I've split a engine with 350000km (a bit over 200k miles)
No visible wear, sylinders would not need honing, rings were good to go another round, basically no need to change anything...
This was after i drove it 4-5 miles with no oil, cam locked eventually and t-belt broke.

Ive seen a engine with over 520000km (323k miles), no oil usage, headgasket still held up, good compression.

These are wery durable engines when properly maintained, never heard of a failure on a stock engine except when people do stupid things. (Example me not tighten the bolts that hold the oil pump in place, bad move)

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[GEE-BEE]

you will be changing the intake and exhaust manifold as the stock exhaust sits lower

pd150 rh facing will work

I bought a ahu with ctn yesterday

Doing the same on a mk1 coupe after paint..

AAZ non egr exhaust, hybrid ko3
techtonics tuning downpipe and 2.5 exhaust

need a intercooler setup let me know

[vanbcguy]

My AHU 'donor engine' was probably around 200,000 miles, I unfortunately don't know EXACTLY what it was at but it had a timing belt change note at 232,000 km and the t-belt that was in there was probably only a few months away from letting go.

Mine had absolutely no crank wear and only very minor cylinder wear.  There was still factory crosshatching visible though there was enough taper that it made sense in my case to bore and throw new pistons in since I was building for performance rather than economy.  If my goal was low cost I could probably have just put a new timing belt, water pump and seals on it and called it a day.

[the caveman]

My AHU now has 480,000 kms. I had to open it up 2 years ago (at about 450,000) because I sucked in some water in bad weather. I expected to see the worse, but wanted to see if it would be worth rebuilding. Other than 2 bent rods and one scratched piston skirt, it looked more than fine. Hone marks still on the cylinders,no ridge at the top.I ended up using a stock sized piston to replace the damaged one.I think I can get another 300,000 kms with any luck

[Toby]

I have an ALH in a 2000 Jetta with 355K miles on it and 500 psi across the board +/- 5 psi. I was into my wifes ALH with 256K on it and there was very little ridge and nice smooth bores. It ran away before we got it and hurt itself in the process. Other than  damaged piston and some tiny scratches in the bore everything else was fine. I reused the main bearings and could have reused the rods as well. This things are super durable and long lived as long as you keep clean oil in them.

[DRP67207]

Thanks for all the replies, that helps a lot.  That's kind of the impression I had from reading on here and elsewhere, but it's nice to have the durability of these engines confirmed by a few here.  Sounds like low 200K should be all right provided the previous owner wasn't too rough on it, now to just track down the right donor... I'll be going for reliability and economy rather than power, even stock should be plenty of power for my needs in such a light truck, so I'm not going to be putting a lot of extra strain on the internals.  Thanks again.

[damac]

So if you get a "nice" 200,000 mile motor, no need to do rings and head gasket job just for the hell of it before daily driving?

This is one of those situations where you shouldn't touch what isn't broke?  

[libbydiesel]

If you don't know when the timing belt has last been changed, then of course you should change it on ANY of the VW diesels. 

Just to add my own data point to the mix, my '02 jetta wagon just passed 240,000 miles and runs flawlessly. 

[theman53]

01 TDI jetta runs great at almost 300,000

[vanbcguy]

Timing belt and water pump should be done on any engine without absolute certain history. Even if someone says it has been done recently the cost of failure basically junks the car when you are talking about something this old.

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[damac]

woops that was dumb of me to lump the timing belt job in with that question!

i always do the same on my motors thus far, i don't care what anybody says i want to start fresh with name brand parts.

[Smoker]

The 3 ahu's I currently own all have 32x,xxx miles. I haven't had any of them apart yet, but 2 of them run 100%. The third... well, that's another story.

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[xsp2467]

I currently daly drive my 81 caddy electric AHU swap with 320k miles on it and compression is higher then normal across all cylinders and oil pressure is spot on too. I also have a vnt-15 on it and Titan .205 nozzles with a tune that makes it put out a comfortable 120hp.

[iamdieselnutmechanic]

Over 500k km's all original. Been beating its ass for the last 80k.. and it just did a 4200km trip in 4 days.. Very little oil usage, and still within spec on compression.