Thread: Intermittent noise 300tdi

Okay, I tightened all of the IC hoses yesterday and it was still making the slipping belt like noise. So I checked a few other things today and amongst other things, the A/C belt or tensioner bearing started squeaking and sort of ticking a little after I sprayed some water in it, so it may need a bearing (which I have). A bit of water sprayed into the edge of the bearing quietened it down again, so it looks like I am back to the intermittent tappet like noise.

I will look at the caps again and see how all the push rods, pedestals and tappet arms look like whilst I am there. The search goes on... <insert twilight music here>

Cheers,
Tom.

Originally Posted by BathurstTom

Okay, I tightened all of the IC hoses yesterday and it was still making the slipping belt like noise. So I checked a few other things today and amongst other things, the A/C belt or tensioner bearing started squeaking and sort of ticking a little after I sprayed some water in it, so it may need a bearing (which I have). A bit of water sprayed into the edge of the bearing quietened it down again, so it looks like I am back to the intermittent tappet like noise.

I will look at the caps again and see how all the push rods, pedestals and tappet arms look like whilst I am there. The search goes on... <insert twilight music here>

Cheers,
Tom.

do you mean twilight zone? twilight and twilight zone are very different. one of those would suggest you grew up in a cool era and the other would question your sexual preference.

good thread though. im very interested in the noises threads as mine is similar. i have had bad tappety noises as well as clunk noises. thought it was very loud injector noise but turned out that two of the bolts which hold down rocker shaft had either come loose or i had not tightened them properly. so it threw all of the clearances out. once i tightened and redid the valves the noise went away.

Originally Posted by Fausto79

do you mean twilight zone? twilight and twilight zone are very different. one of those would suggest you grew up in a cool era and the other would question your sexual preference.

good thread though. im very interested in the noises threads as mine is similar. i have had bad tappety noises as well as clunk noises. thought it was very loud injector noise but turned out that two of the bolts which hold down rocker shaft had either come loose or i had not tightened them properly. so it threw all of the clearances out. once i tightened and redid the valves the noise went away.

Definitely Twilight Zone - I have heard of the other, but have not seen it!

Cheers,
Tom.

I am actually leaning to a manifold leak causing my problems now. I thought I had it figured out when I looked at the main belt tensioner - the bearing was a little noisy and loose. I replaced the bearing and it made no difference to the squealing noise. The car has good power but sounds just a little "chuffy" and makes the belt like noise under load only. Very much like described in this thread.

300Tdi Turbo Squeal

I did order a gasket and injector seals, but they were not sent yesterday as they were busy . I wish Roverlord were not on holiday. else I would have ordered them from Mario and Heather.

Cheers,
Tom

Looks as thought the "belt like" noise is actually the uni joint on the front prop shaft, the rear one near the transfer case. Visible movement. I have a spare uni joint here, but looks as though I need to wait until tomorrow as the rain has only hust broken here.

Tom.

Well I pulled the rocker shaft off of the motor and I found that number 5 rocker (exhaust valve on cylinder 3) was quite pitted - it looked like the valve had been hammered back at the rocker. So I suspected that the valve may have been hitting the piston. Thinking about this, I wondered why this would be on only one valve. I decided that perhaps I had mistakenly fitted an intake valve (slightly larger) into the exhaust and vice a versa. So I pulled head off to investigate. Nope. No damage to valve pistons or head, all look spot on. No visible play on the conrod bearings. So I pulled out the cam follower on that valve expecting wear or a breakage. No, perfect. I have a new rocker and pushrod on the way (thanks Roverlord), which I will replace, although the pushrod appears to be fine. I have also ordered a set of lash caps (hardened pro comp vw 8mm from US of A - VW PRO Comp Hardened Valve Stem Lash Caps FOR 8mm Valves SET OF 8 Empi | eBay) as the nearly new ones look shot already with only perhaps 5k on them.

So the mystery continues...

Tom.

P.s. The valve in question appears to be free - tapping it lightly with a hammer appears to move it as much as other valves

What are the threads like in the alloy head which secure the rocker shaft and have they been helicoiled or similar in the past?

When the threads in the alloy head go and/or the helicoil insert starts to fail you'll get a tapping noise. In my 300tdi it initially showed as a mystery tapping noise where I jumped through all the hoops you have. Resigning it to the "... eventually something will break so wait..." file eventually there was oil on the driveway from a leaking tappet cover. When I went to tighten up the three nuts which secure the tappet cover, #3 rotated freely. See my thread for details of the fix.

If you've also had to tighten up your intake and exhaust it suggests that the head has been cooked or has gone soft, so a hardness test might be warranted.

that last comment has me worried. i put new turner head in mine. but when i first started it up i swear it was running more smoothly. not sure bout the tapping sound being there then. it got hot very quickly but i did switch it off straight away too.
redid coolant to get airlocks out. seemed ok but still would warm up fairly quick although would then stay at correct temp according to my ems2.

after my radiator had a bit of a leak i had it filled up professionally when they fixed that and it took longer to warm up. but i swear it runs fairly rough compared to when i first finished. and has knocking sound. which i dont know if was there before or not.

i had loud tapping sound at one stage and checked the valves and two of the nuts on rocker shaft were unwound halfway. retightened and set valves again and ran smoothly but still that knocking sound. im hoping i did not cook the head. even though i was very careful but i did drive it a few times before the professional fill and with a small leak somewhere. so hoping there wasnt a hot spot somewhere in the brand new head. now im worried.