1999 AFN 1.9 TDI engine LOUD ticking

[johnbuz]

Hi

1999 Alhambra 1.9 TDI (110 BHp) Manual

I have a weird fault that is driving me mad.

My engine is making a LOUD (VERY LOUD) ticking/knocking noise, sounds like it is coming from the cam belt end of the engine, high up. It is the same whether the engine is hot or cold.

The noise sounds at its worst when stood by the drivers side front wheel.

I have replaced the following:
Cam shaft, hydraulic cam followers and injectors. (Oil and filter change too)

These have made absolutely no difference to the noise at all.

With the engine heald at about 1200RPM I have cracked the diesel feed to each injector in turn, this makes no difference to the noise. (This isolates the firing on each cylinder in turn)

So......doesn't seen to be cam based, doesn't seem to be piston problem.......engine drives completely normally, no performance issues.

Idles normally (apart from the Bl**dy noise) and revs cleanly.

The injection timing checked with VAGCOM and is very slightly advanced, but well within green line on TDI timing graph, cam timing checked and spot on. Timing marks on flywheel and crankshaft cam belt pulley are in alignment, so no creap on cambelt pulley in relation to the crank.

It has started overheating recently, although i had just drained the coolant out completely and refilled. I'm not convinced that I have all the air out yet.

Any ideas?

John

 

[allh2k]

Does it make the noise with the aux belt off?

Could it be the power steering?

Most people think of the tappets when its a loud tapping noise from the top of the engine, could it be these?

I have just had a new clutch on my alternator but this was only clicking when cold.

Does the noise increase with the revs?

 

[johnbuz]

Hi

yep noise there with both belts off.

replaced hydraulic followers with new, just had them out again to check they had pumped up - yep they had.

yes noise is in time with the engine, defo mechanical in nature.

Very loud knock/tick, can be heard from 400 meteres away.

John

 

[Muttley]

The only thing that's left is the water pump. Did you not change this when you had the cambelt changed?

 

[johnbuz]

Hi Muttley

The water pump is driven by the same belt as the power steering, noise does not change with the belt off. So not the water pump!

John

 

[muddyboots]

Only things left that I can think of:

1) Fuel pump
2) Oil pump
3) Major bearing problem - ie big-end or small-end conrod bearing, or crank bearing

Did the noise just suddenly start, or has it gradually increased over time ?

 

[allh2k]

are you sure about the water pump? mines the 110 ASV and im sure it runs off the cambelt was the AFN built different?

 

[johnbuz]

Hi Allh2k

Cam belt drives cam, and oil pump via jockey shaft to the vacuum pump and then down to the oil pump.

Changed Vac pump too - no diff in noise.
John

 

[johnbuz]

Hi Muddyboots

Bought the car with a diagnosed 'headgasket failure' atually the head of exhaust valve 3 had come off and grenaded the head, piston and injector on pot 3, shrapnel throughout engine.

So I bought another engine from a breaker 'Nice engine mate - runs lovely' yeah right, anyway did a deal and am now trying to sort this engine out.

So it has made this noise since I first flashed it up, hasn't got any worse, and I haven't been able to change it in anyway - so far!

Fuel pump - yes thought about that, but it is such a heavy noise I think the pump would not function??? Listening with an engine stethoscope the sound seems to be coming from the head/block and not the ancillary gear ie alt, injection pump etal.

John

 

[Muttley]

Some confusion here. AFN is listed in my old Ibiza manual as a TDI 90 engine, not 110. However, if it has an external water pump then its built on the older TDI block. Does it have a wastegate turbo or variable-vane?

Have you been able to run the engine with the upper cambelt guard off, so as to observe the idler wheel and tensioner? A duff tensioner might make a ticking noise. You might also be able to see if there is anything loose on or near the pinions that might be making a noise.

 

[johnbuz]

Hi Muttley

Engine stamped as AFN rated at 110 BHP with VNT turbo and the larger Bosch injection pump with the cast ribs on the side, not smooth like on 90BHp version.

Water pump is mounted on the end of the engine attached to a ali casting that is bolted to the front of the engine, thermostat is at the bottom under plastic cover, it is driven by the same V belt as the power steering pump. Serpentine multi ribbed belt does AC and ALT. Cam belt does cam, and oil pump via jockey shaft to vac pump and then down to oil pump.

Yep run engine with top cover off, no noise from tensioner or top idler - the noise is too heavy for either of these.

I'm guessing it will be either be excessively worn valve guides or small end bearing (gudeon pin), noise too high for crank bearings or big ends. Time will tell.

I am pulling the head off soon, and then maybe pistons out to examine con rods and associated bearings. hopefully I can get away without pulling the entire engine as it is a bitch of a job on these Alhambras.

John

 

[johnbuz]

Hi

Just had it looked at by my local garage who did the MOT, he thinks it might be a cracked piston.

So off with its head and sump, and let the dismantling begin!

Runs fine, even passed the emmisions test with flying colours!

John

 

[allh2k]

how much are pistons these days? or would u get a scrappy one?

 

[johnbuz]

Hi
Scrappy one I guess, but I will price new ones too.
John

 

[brightsideteeem]

passed emmsions test's? Do you mean smoke test?

So its not smoking loads when you rev it?

 

[johnbuz]

Yep passed smoke test, well within limits.

No smoke at all when you rev it, hence now thinking either small end bearing or cracked piston skirt.

Wife away on a course this w/e so I wont be able to touch the car for a few days as i have the kids.

John