Thread: td5 strange sound after head gasket replacement

The TD5 had a warped head problem at the end of last year (see http://www.aulro.com/afvb/showthread.php?p=2142267). I never found how much it was warped, but it was good enough to be skimmed and put back together. The head gasket actually looked ok - I could not see any part where it blew. The head work included new valve guides, inlet valves and so on.

It never used any water, nor did I see milky oil or anything in the coolant. After the head work was done the coolant pressurization issue went away, and the coolant is still stable at the same level. I've done about 45 hours of driving since the head work was done.

At the same time the oil cooler was replaced as well - it was on its last legs as well. It got a service as well at the time, and an "ERC diesel additive" was added.

Before the head gasket replacement the only "problem" the TD5 had was the pressurizing coolant system. No funny sounds at all.

Now, after the head gasket replacement, it has a new clack sound that appears:
* Not very loud after you've started it from cold - while idling it feels like the engine shakes itself every time the noise is there. Almost as if it shuts down momentarily. It is not very obvious when it is cold, but I notice it now that I know what it sounds like when it is hot.
* Quite loud if you start it about 10 minutes after a long drive - i.e when it is hot. The shaking is less obvious then.
* It is not a "rhythmic" noise - it is irregular in beat.

The sound disappears as soon as you get the revolutions up - stationery or driving away. It does not sound like the noisy tappets I had on the V8 where it would tick away while driving. After a few minutes of driving the sound will just go away if you let it idle again. Similarly if you let it idle (clack clackity clack) for a while it will also go away.

The indy has replaced the harmonic balancer with another second hand one - so I don't think it is that. The fuel pressure regulator had started leaking quite badly lately, so I had that replaced this morning. Sound is still there.

I've attached a sound clip - it sounds *much* worse on the clip than in real life; I think the phone does some strange sound adjustments every time the clack happens. Listen to sound.mp4

Originally Posted by Disco Muppet

^ This.

Ok - I'll see that this is checked. Can incorrect injector travel adjustment result in random clacking at idle only, or would it also show at other revolutions?

I forgot to add earlier - performance is really great, so we did not suspect a sad injector.