Join Date: May 2002
Location: Tring, Hertfordshire
Alfa 156 2.4 JTD - Strange noises : request for help
I have a 156 with the 2.4 JTD engine. The car is just over four years old and done approx. 73k miles.
The timing and aux. drive belts + tensioners were all replaced about 10,000 miles ago.
Recently the engine started making a peculiar 'ticking' noise which rises and falls with the revs of the engine and is about half engine speed. It came on suddenly and over the course of a couple of weeks got progressively louder, but there has been no perceptible drop in performance.
My local dealer had the car, looked at the tappets, cam etc and couldn't see anything wrong. Their next course of action suggested was to take off the cylinder head to check for broken valve springs, and then to take out the pistons to check for any problem with the piston rings.
I took fright at the projected cost of all this and took the car instead to a local trusted motor engineer who specialises in diesel engines.
They checked the timing, no problem. He checked the tappet 'gaps' and they all, more or less, seem to have slipped outside the tolerance of the Alfa recommended settings (despite what the Alfa dealer said). They adjusted the gaps temporarily by shimming out the valves, but the noise was still present.
If it were a broken valve spring for example, as indicated the gapping problem and the noise, why would they all go at once ?
So, it seems that there could be two separate problems, something that caused all the tappet gaps to move (assuming they were correct from the factory in the first place), and something that is causing the ticking noise.
Broken camshaft and/or warped cyclinder head would presumably have an impact on peformance plus much worse noises or head gasket troubles.
Does anybody have any idea, no matter how daft (I once had a Mini years ago that blew a hole in the exhaust manifold and made a similar noise, for example), about what may be causing either of these ?
A worn cam perhaps, would that do it ?
Does anybody know where I can get the spec/measurements of the factory camshaft from ?
Any help very, very much appreciated.