MK2 tappets

[ianmaxtec]

Just serviced my MK2 gti. Oil filter, plugs, air filter and oil. The car has been using semi synthetic 10W40 for the last number of years, however this time round I decided to use multigrade oil, as this is the oil the engine was designed to run on.  However when I finished the service and started the engine, the tappets (well I think it’s the tappets) were much noisier. I then (out of desperation) drained the multigrade oil, and replaced it with semi synthetic 10W40…. no difference, still a very loud knock on tick over, strangely when I rev the engine it seems to disappear.   Any suggestions would be welcome

[Ben Lessani]

... Waiting for SCP to comment

Sounds like blocked channels/low pressure, run an engine flush through - or a litre of ATF with your engine oil for 100 miles if you brave.

Just to confirm though, is it a knock - or a tick? Tappets don't knock, they chatter, crank bearings knock (plus the sounds comes from the bottom).

I'd do a search for Tappets in the MK2 section - see what comes up

[ianmaxtec]

Its more of a knock than a tappet noise....its also hard to pin point the sound. what confuses me is why did this happen, all I did was change the oil !!!!

[ianmaxtec]

Ben, you mentioned ATF as a possible fix, you also mentioned "if I was brave", what are the dangers with adding ATF to the oil ?

[Ben Lessani]

ATF is a lot more aggressive than conventional flushes, oil that has baked onto the head/block over the past 20 years that would take nothing short of an explosive to remove can be stripped off by ATF.

The problem with this, is that any build up of oil over the years can make up for wear on the components - effectively making a seal. Flushing through with ATF thoroughly cleans out the engine, and can remove this 'protective' film of crap, leading to the engine burning oil / low oil pressure etc.

I ran it though mine and combined with a bunch of things, it fixed my tappet noise, but I wouldn't go recommending it on a whim, especially since my valve stem seals are leaking now more than before I replaced them

[rubjonny]

as above, the atf cleared out all the crud holding my oil cooler together 

[Wayne]

If it is knocking that sounds more than a tappets.

[ianmaxtec]

Tried flushing out with STP engine flush (was not brave enough to try ATF), also changed the oil, again........no joy, still loads of horrible noises!
Is it possible that changing form semi s to multigrade might have blocked / damaged one of the lifters ?

[DarnPB]

Try to judge what speed the noise is. ie, is it at engine speed, or half engine speed. Half engine speed is valve train, where-as engine speed is possibly bottom end. Bottom end will be more of a heavy knock rather than a tap.

[Roverdose]

does the tapping disapear withing 2 minutes of starting? i spoke to a local ledgend in my area after servicing mine, exact same problem, he said that vw say, with the 8v engine, if the noise disapears withing 2 mins then you dont have a problem, if it does continue you do, mine takes a minute and a half at most but only when starting from stone cold, one solution is run it on 15w40 , its thick enough not to drain out of your tappets so quickly, magnatec aswell as it'll stick better!

Hope that helps!