Ticking noise from one bank

[Danblez]

Hi all I have read all the threads titled the same but can't make my mind up what it is. It only starts when hot and if the engine is switched off even for just 5 minutes it almost disappears. I have just had a stethoscope on the heads and there is a pronounced tick which is definitely louder on one side.

I was convinced it was a manifold leak but am now thinking it is something more sinister. I presume you wouldn't hear the tick of a manifold leak with a stethoscope or am I wrong?

Thanks!

[bobfather]

Definitely sounds like a manifold leak. Because you describe it changing with heat I'd suspect manifold head flange somewhere, the gasket material can open and close like a reed valve so the sound comes and goes. The less likely point is the common leak that can form at the four into one connection. First thing to do is check the manifold bolts are tight, those you can access that is. These are known to come loose over time from engine vibration and are check tightened on the major service schedule though most service centres fail to do this due to difficulty gaining access

[Danblez]

Well I have tightened the manifold bolts some were only finger tight! Noise still there though. Have had a hose out and no obvious leaks.

Would a manifold leak sound like a metallic ticking even using a mechanics stethoscope? The noise is the loudest when I am touching the actual manifold but would have thought the stethoscope would only pick up metal on metal noises not an air leak?!

[Pupp]

Assuming the stethoscope has a metal tube end to it, try touching it on the head bolts and inlet manifold bolts. . might be possible to track it to the particular cylinder. The steth will pick up blowing gaskets just by being in proximity to the leak, but I wouldn't expect a leak noise to be anything like as prominent as a mechanical noise on touching bolts etc.

Easy enough to pull the rocker cover on the offending side just to ensure it's not a rocker pad gone walkies... Good peace of mind as if one has split or broken off, the valve end will be getting mangled

[bobfather]

If your bolts were very slack it's likely that the gasket is damage and tightening will no longer seal it. I had this issue last year, I used a metal probe stethoscope but couldn't be certain. I finally tracked the leak down using an unusual method which I'd developed several years ago. I posted it on ChimaeraPages.

Go to the link below and scroll down to the topic named 'Find that elusive exhaust manifold leak' posted when my PH name was TVRBOB

ChimaeraPages Technical Info