Hydraulic tappet noises.

[123-jn]

I had one tappet on the passenger side bank That would drain down every night and take 2/3 miles to shut up so I decided to check the adjustment. I followed the guide in here rather than Haynes and set each preload to 1.5 turns. On the passenger bank one tappet on cylinder 4 was not preloaded at all in fact there was about 1mm of play!! the others all had about half a turn of preload only. I guess this may have been the noisy one!! Having reset them all after a mile or so things quietened down but the constant tick tick of one tappet continued as before so I reset them again. All the lock nuts were still tight but on cylinder 4 the one that had been out was still perfect 1.5 turns the other had lost a turn of preload? now only half a turn? all the rest were fine. Now all reset again and I reckon we still have a tap tap from one of the tappets so perhaps one is duff. The problem is how do I tell which one is duff? I cant afford to change them all!!

[blacky]

Why not remove rocker covers with engine cold and turn engine over by hand till rotor arm points to cyl 1 then see if you can feel play on that cyl's rockers. repeat this for other 3 cyl's

[itchyfeet]

in the past I have used a length of tube to find the source of noise, it's surprisingly accurate, take the push rod tube covers off, one end of the tube to your ear and move the other end from one push rod tube to the other, where the noise is loudest is the problem.

Probably need to jack up the van to do it, solid pipe is better than flexible tube.

Like a stethoscope

[kevtherev]

nice tip itchy

[123-jn]

Thanks for the suggestions, none seem to have any play in now when at TDC but the tapping lets louder as the engine warms up and its from the left passenger side bank. I will try the tube method with the covers off sounds like a good idea. I wish they didn't anchor the pushrod tube covers to the exhaust studs!!!

[kevtherev]

that suggests either your oil pressure in the lifter gallery is low
or the return springs are worn out or the oil hole is bunged up.
I believe Ian Hulley had this issue and cured it with a lot of oil changes in short order

[Ian Hulley]

I believe Ian Hulley had this issue and cured it with a lot of oil changes in short order

Yep, that was nearly 10 years back when we bought The Bus ... it had done 80 miles in 3 years and I almost had to dig the oil out with a trowel 4 or 5 changes of oil (when hot) and the problem went away. Back then we had a 400 gallon tank of the engine oil in the workshop so I just ran it through the van for a day and poured it back into the oil tank.

Ian

[vanisveryrusty]

When was the last oil and filter change carried out ?
What oil are you using?

[itchyfeet]

I wish they didn't anchor the pushrod tube covers to the exhaust studs!!!

MIne no longer are, when I first took them off I decided that was a daft idea so I just stretch them over the studs and fit the lower bolts, don't need to be held by nuts on the exhaust studs.

[123-jn]

I was using 15-40 semi synth which I did approx. 1000 miles on after buying the van (tappets sounded ok but one had a slight ticking) . On returning and hearing the engine tick over with the lid up I decided to just check the preload in case it was simply this. I discovered all the tappets set to around half a turn or less and a valve on cyl 4 had drained down. I ran the engine to pump up the tappet and set the preloads to 1.5 turns as in wiki. At the same time I changed the oil and filter again this time 20-50 Halfords classic mineral oil as advised by some vw fanatics I met. Engine ran bad for a minute or two then smoothed out as the tappets adjusted. It sounded ok so I went for a drive. AS the engine got back to full temperature a loud ticking could be heard from the engine. Left bank again. I popped the rocker boxes off and checked the adjustment again. This time the other valve on cyl 4 had drained down in just a couple of hours. I've reset them all again ( only the one was a problem but only half a turn less once the tappet was pumped up) Now I ve added some hydraulic lifter treatment that I used on my hdi Picasso to good effect. Looks like I may have to remove the lifters from cyl 4 and clean them out if this doesn't help. Those tubes and seals are not cheap are they !!!

[itchyfeet]

I think the thicker oil will get into the tappets in time one drive is not enough
Telescopic push rod tubes are expensive yes but cheaper then removing the head and less risky