Rattle from back of rocker?

[missfire]

Originally Posted by MikeNZ

Exhaust manifold leak? My leak sounded like lifters, but is much louder under acceleration.

now here is an old thread..

same here on the 100 turbo, so loud, i was getting worried... sounds like a tappet on cyl.5 but very loud. didn't flush this car but put new oil in it, maybe a bit thin..? 5w30?
sounds like a tappet getting no oil supply at all.. goes away at 3.5K ish (as oil pressure increases..?) almost sounds like its coming from the wastegate sometimes.

the red 2.0 i run sounded similar when i got it, flushed it, 'thicker' oil, only 'taps' until its warmed up now. then silent.

any opinions on the 100 turbo..? it had 10 new tappets installed about 25K miles ago.

thanks.. need to put my mind at ease.

oil pressure on the gauge runs at either 2 bar or 4 bar, never anything in between, i presumed a dodgy sender..?

[Phil Payne]

Originally Posted by joe90

I was told by a mate who has been buying, selling and running audi's for over 20 years that the fith cylinder lifter doesn't get enough oil, ...

Bollocks, not to mince words.

However - you'll notice that the lifters are not quite directly under the cam lobes. Each time the lobe comes down, it imparts a small tangential force to the lifter so that it turns to spread wear uniformly over the upper surface.

Sometimes you get a 'cyclic' lifter - tap taP tAP TAP TAp Tap tap. On a solid lifter engine, this is caused by a piece of detritus under the shim - on a hydraulic lifter car, it's a sign of the lifter starting to fail. When the lifter inlet oil inlet hole is opposite the feed hole in the block, it pumps up and goes quiet. A few seconds later and the inlet hole is 180 degrees away and a failing lifter will collapse a little, giving a tick.

The trick is to listen very carefully and try to discriminate the lifters from one another. The cycle is usually about five seconds, but varies along every engine so you will sometimes hear 'beats' and sometimes just a general racket.

[Phil Payne]

Originally Posted by missfire

same here on the 100 turbo, so loud, i was getting worried... sounds like a tappet on cyl.5 but very loud. didn't flush this car but put new oil in it, maybe a bit thin..? 5w30?

FAR too thin for an Audi 100. 20W is a usual minimum - 15W in emergencies.

Don't bother with synthetics - they weren't thought of when this engine was designed. Halfords Mineral Enhanced 20W/50 - a third the price of Synta Gold so you can change it every six months. After three changes the inside of your head will gleam and your tappets will very likely shut up for good.

[Phil Payne]

Originally Posted by missfire

oil pressure on the gauge runs at either 2 bar or 4 bar, never anything in between, i presumed a dodgy sender..?

Sticky oil pressure relief valve. It's above the sender right at the front of the engine, just behind the harmonic damper. Take the wire off the sender and wind it out - the sender, spring and pressure relief plunger should drop into your hand, along with about 50ml of oil. Make sure the plunger isn't scored - be especially careful inspecting it if you need to fetch it out with a magnetic pickup tool.

Good threads never die.

[missfire]

Well! thats exactly what i need to know!

So my 5w30 is just a bit, em... sht then..

Will have a look at the relief valve also. I had a look/go at removing one of the hoses from the oil cooler to drain that also..but i could 'feel' trouble emanating from the spanners (so tight i had visions of sheering the cooler in half before the union 'cracked' open.) so i left it.

20w 50 it shall be. i always used to like running 'thicker' oil in my old volvos, to quieten then down a bit, so have no doubt this will be exacerbating the problem, thanks.

When the lifter inlet oil inlet hole is opposite the feed hole in the block, it pumps up and goes quiet

i think this happened once on my last journey.

[b3robo]

Missfire, have you had any good results from using thicker oil? i've got diz noise from mine when I rev from 2000rpm then let off the throttle. I've had a brand new Bosch distributor in there, new timing chain, tappets are apparently fine and the noise remains...

[missfire]

Originally Posted by b3robo

Missfire, have you had any good results from using thicker oil? i've got diz noise from mine when I rev from 2000rpm then let off the throttle. I've had a brand new Bosch distributor in there, new timing chain, tappets are apparently fine and the noise remains...

not yet! only found out that i need thicker oil yesterday.

will do another oil change next weekend and post the results.

[pimpdriver]

Originally Posted by Phil Payne

FAR too thin for an Audi 100. 20W is a usual minimum - 15W in emergencies.

Don't bother with synthetics - they weren't thought of when this engine was designed. Halfords Mineral Enhanced 20W/50 - a third the price of Synta Gold so you can change it every six months. After three changes the inside of your head will gleam and your tappets will very likely shut up for good.

My Audi 80 B2 and my 100 C3 both specify 15W40.

Or so I thought???

[b3robo]

I've also been reccomended 15w40, not sure I wanna put Halfords oil in though, may give it a try tomorrow!