1.9 TDI BLS A3 - Bottom end bearing knock

Honest John Back Room » Technical matters
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Sat 30 Nov 2019 00:09
1.9 TDI BLS A3 - Bottom end bearing knock - Roy Brown

Took as a trade 1.9 tdi PD engine only 100k with regular services. Engine sounds fine ticking over, has had a new camshaft kit so looks like its the bottom end bearings knocking

What I want to know is can these bearings in the bottom end be changed without having to do any further work like regrind the crank etc

Or does that really depend how badly chewed up the crankshaft is?

It is only a cheap run about that I was hoping to use as a second car for travelling a few mile to and from work

Edited by Roy Brown on 30/11/2019 at 00:10

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Sat 30 Nov 2019 10:35
1.9 TDI BLS A3 - Bottom end bearing knock - Big John

The 1.9 pd is usually a very long lived engine especially re the bottom end. Typically on any engine big end noise gets MUCH worse as the engine oil gets warmer/thinner where oil pressure fails to stop metal to metal contact between crank and big end shells(death rattle!). If your engine ever gets to this stage of decay then it's really an engine out job to strip and check everything as probably the crank will be damaged/scored/worn oval etc. You also have to thoroughly clean everything as when the engine self desctucts tiny bits of metal cause havoc! When things get this bad the oil has a distinctive smell!

Are you really sure it's the big ends? - if it is then I'd consider another engine.

Why did it have a camshaft kit? and were the pd unit injector rocker arms changed?

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Sun 1 Dec 2019 13:00
1.9 TDI BLS A3 - Bottom end bearing knock - focussed

Don't forget any diesel can suffer with injector knock if an injector needle is stuck open causing the injector to "hose" not spray properly. Sounds just like a really bad big-end bearing knock usually on one cylinder only.

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Wed 4 Dec 2019 23:56
1.9 TDI BLS A3 - Bottom end bearing knock - Roy Brown

Would that show up on a scan with diagnostics?

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Thu 5 Dec 2019 08:18
1.9 TDI BLS A3 - Bottom end bearing knock - craig-pd130

Don't forget any diesel can suffer with injector knock if an injector needle is stuck open causing the injector to "hose" not spray properly. Sounds just like a really bad big-end bearing knock usually on one cylinder only.

Good point, and the PD motors could sound a bit 'knocky' even when new simply because they were only designed to pass the emissions standards of 12+ years ago - and the PD injection system could sometimes overfuel. I had a Passat PD130 from new, and when I booted the throttle in gear, it would sound a little knocky.

As it's had a camshaft swap, perhaps the injector timing hasn't been dialled back in correctly? The PD engines have slots for the bolts that hold the pulley to the cam so that the timing can be fine-tuned for optimum running. See this article here:

http://www.autospeed.com/cms/article.html?&title=Big-Changes-from-Tiny-Adjustments&A=112521

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Wed 4 Dec 2019 23:55
1.9 TDI BLS A3 - Bottom end bearing knock - Roy Brown

Yes you are correct but on this BLS code whatever parts they used bottom end knock on this code seems to be common.

The camshaft kit was replaced as on inspection one of the buckets where badly worn, so thought that was the issue.

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