Intermittent 'pinking'

[T33stat]

Hi all,

My car has an intermittent 'pinking' noise coming from the engine, it's a weird noise and I can't quite put my finger on it, I'm thinking it may be dodgy oil...

The car had been sat for a couple of years and I haven't done a service on it yet, this is my first step, I have the parts but recently moved house so haven't done much in the last 4 months!

The noise comes and goes consistently in intervals, there is around 5 seconds of smooth sound and then 3-4 seconds of ting ting ting ting.... Then smooth again...

I'm thinking there might be some oil flow issues or just some dirty oil...

The car doesn't idle funny, drop revs or cut out... Just the noise...

Any ideas?

Thanks

Ryan

[Nate]

So it does it all the time, regardless of whether the engine is working hard or idling?

Does it vary with revs?

[T33stat]

Yeah it does it both idle and when being revved, more noticeable when idling as there is less noise, when revving the cycles are much quicker, but yeah it still goes noisy/quiet/noisy/quiet....

I thought it could be the timing belt slipped a tooth but think it's way to slow for that...

[mark1gls]

Change the oil and see if it's any better, could just be the tappets.

[Nate]

Without hearing this, it's going to be virtually impossible to diagnose. But my wild stabs in the dark would be (in no particular order)

Pulley running out of true and fouling something. This would be obvious from looking with the engine running

Timing belt wandering and catching it's cover or the block

Loose heat shield (less likely, but not impossible)


Stuck a biT of hose in your ear and use the other end to direct your hearing to see if you can pinpoint where it coming from

[bluestreak56]

Is the fuel 4 months old?

[the edmundator]

Is the fuel 4 months old?

Don't see why that would make any difference. I regularly leave my cars off the road for 6 months and drive happily on the fuel that is, obviously, substantially older.

Contaminated fuel might be a problem, but I think petrol has to be very old indeed to not work (or contain a high percentage of ethanol, which is hygroscopic).

I just filled my lawnmower's tank with petrol that's been in a plastic fuel can in my shed since last summer and it started first pull on the cord.

[T33stat]

The car had about 1/8th of a tank of old fuel, I recently put in 30 litres of optimum to try and clear it out a little so would say it's not the fuel, my first port of call will be the oil and see how she sounds :)

[duggers]

Possibly a sticky hydraulic lifter. Do a flush and oil change using suitable grade.