HYDRAULIC TAPPETS

[OLD ONE]

Do hydraulic tappets ever get stuck?? I know this may sound daft, but I started my van this morning after standing for about a month..and it was very tappety, or small end knock? Checked oil etc all OK. If it is a lifter will it free of if I run the van for some time.
Checked Wiki, can find nothing about sticking lifters. Any ideas? A bit dubious using it until I sort out the noise.

[AdrianC]

Do hydraulic tappets ever get stuck?? I know this may sound daft, but I started my van this morning after standing for about a month..and it was very tappety, or small end knock? Checked oil etc all OK. If it is a lifter will it free of if I run the van for some time.
Checked Wiki, can find nothing about sticking lifters. Any ideas? A bit dubious using it until I sort out the noise.

Not stuck, but drained down. As you run it and it warms up, that tappet will refill and pump back up, then go quiet again. It might take a little while of driving to do it, but at idle it'll take _ages_.

In the meantime, no harm to anything but our eardrums.

[OLD ONE]

Thanks..AdrianC... That is a relief

[Ralf85]

A good 20 minute drive at a steady 40-50 mph should resolve the problem. This will recur if you leave your van unused for weeks.

[CovKid]

Hello again Old One. Hows that lovely friend of yours with the Royal slippers?

[OLD ONE]

Hello again Old One. Hows that lovely friend of yours with the Royal slippers?

PMd

[VERAT25]

good post this/ i was about to post on this subject, as i have same problem? advice given is spot on to what i have been told earlier this week,
may need to get the old girl out, and give her a run

thanks

verat25(cardiff)

[California Dreamin]

The 'old' hydraulic 'drain down' senario, is very common to the wasserboxer engine. Some get away with it never happening whilst others suffer repeatedly, usually after long periods of non use.
Generally excepted that thicker recommended oils (15W40) minimize the frequency that these episodes occur.
Very concerning when it happens the first time as you can't quite believe how piggin loud it can be and just how long it can take to clear....pattern normally is....evacuates the air pocket in the tappet element once the oil reaches full running temperature 15 - 25 minutes.

Martin

[itchyfeet]

What amazes me is that people can be on this forum so long and have never read about this
The subject comes up frequently

[jpennington]

Yes, a familiar subject. BUT - it occurs to me that although a thicker oil will take longer to drain down, a thinner oil (5W40 for example) might pump up faster.

My bus first exhibited this phenomenon in February 1990 after being parked for a week in the Alps south of Munich. Temp around -5C, took about 30 minutes to clear. Susequently it has tapped occasionally, maybe once every 5 years, usually when its due for an oil change.

jp

[kevtherev]

Yes, a familiar subject. BUT - it occurs to me that although a thicker oil will take longer to drain down, a thinner oil (5W40 for example) might pump up faster.

My bus first exhibited this phenomenon in February 1990 after being parked for a week in the Alps south of Munich. Temp around -5C, took about 30 minutes to clear. Susequently it has tapped occasionally, maybe once every 5 years, usually when its due for an oil change.

jp

If only it was that simple.
Usually persistent tappers require some readjustment, despite what VW claim, older lifters need less preload, typically 1.5 turns from zero lash. new lifters take more.
this website has it completely covered
http://www.ratwell.com/technical/HydraulicLifters.html" onclick="window.open(this.href);return false;