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Did you ever get to the bottom of the issue ? I suspect your vacuum pump as the noise is intermittent however if you've whipped the head previously there could be that the head gasket might not be the same thickness or indeed one lifter is not filling up with oil...or timing related ! I have seen vans with messed timing belt jobs on which cambelt was a smidge off and valves were kissing the pistons very slightly... Hope you get your motor fixed...
 

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Discussion Starter #22
Hi mate. No, not got to the bottom of it yet. It's still tapping and as said before, only when hot/after a decent run. Having said that, I took a trip to Cornwall in it at the end of November last year and I pulled into the services at Sedgemoor for a listen and to my surprise it wasn't tapping. Next stop in Cornwall and it was tapping again.

Next thing I'm going to try is get it warm and then remove the vacuum pump pushrod, re fit the pump and try that to eliminate it. I have my doubts it's the vac pump as it only does it when hot but I hope I'm wrong. The pump has done 174,000 miles but didn't tap before changing the lifters.

I haven't decided yet whether or not to change the head or swap the cam and lifters for new items. The latter I will probably do that myself, I've been buying in a few tools to do the job, I just need to register my VCDS to read the timing. Not sure if I'll tackle a cylinder head swap though..

Thanks for the reply 馃憤
 

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Get a new vacuum pump and replace it along with the rod, get a pierburg pump if possible, cheap pumps don't last !
 

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Discussion Starter #24
Yes, I'm aware of cheap Vac pumps. I was going to get one from VW if they can still supply them. I have heard they're around 300 quid. I priced a push rod before from them and it was something like 25 or 27 quid plus vat.
 

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The vac pump noise would either get better or disappear when applying the brakes hard. I would have someone experienced listen to the noise as most problems are common on these engines. They will do 500K + if looked after.
It could be a sticking valve or static timing out too. If the latter then expanded under heat the valves may be just clipping the piston tops. If the crank pulley is worn it can cause the static timing to move slightly too. That might be another area to look at. Also worn dual mass flywheels can clatter about & get much worse when hot. Hopefully you'll find the culprit.
 

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Discussion Starter #26
Tried the brake pumping trick and running the engine with the servo vac pipe disconnected. Makes no difference to the tapping noise, that's why I have my doubts it's the vac pump, That and the fact it didn't make that tapping sound before having the lifters changed.

I've had a few people listen to it and none of them can say whether it's lifters for sure. One mechanic said If it were the lifters it would do it all the time, not come and go like it does. Another guy, an engine builder swears it's the vac pump and the engine sounds sweet otherwise. But, yes, I could do with a proper expert to listen to it to be honest but finding one is a nightmare. Most garages I've spoken to either aren't interested or don't bother getting back when they say they will. As the old saying goes, If you want something doing properly, better off doing it yourself.

The crank pulley is ok, had it renewed (genuine part) 3 belt changes ago. I've inspected it myself and it looks good.

The mechanic who did the job said it could possibly be a weak valve spring (or springs) causing it.

Someone else I spoke to said, Did you do a "Cam Burn" when you fitted the new lifters ? My reply was, No Idea as I didn't do the job but I guess not. He then said Well, those lifters will be scrap then as you're supposed to run the engine from cold at 2000 rpm for 20 minutes to burn in the new parts using a running in oil. (don't fancy that idea though with new parts)

I'm yet to check the timing myself so that will be interesting :) It starts and runs ok but as I understand, that doesn't mean it's right.

The dual mass is probably due to be changed, it's done 74,000 miles on the current one so it's probably on borrowed time. I'm pretty sure it's not related to this tapping sound though.

Thanks everyone for your help/Comments 馃憤
 

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Discussion Starter #27

I managed to upload a video on YT for anyone interested in hearing this rattle I have. It's difficult to hear it properly but see what you think ?
 
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