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Hey guys,

I've had an annoying noise coming from my engine bay for about 12 months. I'm guessing its not a lifter tick because the noise only occurs while accelerating. I have taken it to an exhaust shop for a leak test and they said there was only one pin hole leak behind the cat, and that they didn't hear any unusual noise. The header gaskets look good and i can't see any evidence of them leaking but i could be wrong. I'm not sure how an exhaust leak test works and if it would include checking the header gaskets.

The car does have the DOCH ej25, apparently prone to head gasket failure. however i don't have any overheating problems (apart from a leaky radiator ), no water in the oil, and no frothing/bubbling coolant. Is it possible to have a HG leak with no noticible problems apart from a sh ty noise?

What do you guys think it is most likely to be?

Cheers,
Rhys

Could it be a bearing - I'm going with this line since you've said that you only hear it while accelorating, meaning the engine is under load and other components are moving as well.

Your not hearing detonation are you? It sorta sounds like there's a ball bearing bouncing around in your motor. If that's the case you could have a dodgy knock sensor.

Hope this helps out.

Cheers

Bennie

A good thing to do here would be to try and get a recording of the sound and post it up here (easiest way would be a short video with a digital camera probably). Hopefully it comes out in a recording.
Maybe one of your inner CV joints is on the way out, I had one once make abit of a noise under acceleration.

I should have said it is a hissing sound that is intermittent and becomes faster as the revs climb, just like a lifter tick would exept it is only audible when accellerating. I'll try to get a decent recording later tonight.

Sure its the engine not gearbox? Have a feel on your gearstick, bellhousing for "clicking" feel....

I know it sounds nuts, get a long screw driver and go various parts of the engine to see if you can hear the tick noise coming from specific location? Worth a go I guess.... I would if it was me..
Cheers
AP

Ok sound recording was successfull, sort of. My exhaust sound awesome while i'm driving, but you can't hear another bloody thing because of it. With the bonnet up is even worse, all you can hear is the horrible death rattles of my altenator.

Its definitely a hiss, not a tick. I can't hear anything unusual with the screw driver to the ear trick.

mmmm oh well at least you tried... mmm
Is the engine running nicely/smoothly? Is there any inlet leaks (inlet manifold, hoses to attach inlet pipe etc) or inlet manifold gasket leak? (couldnt be possible but anything is possible)
Cheers
AP

Thanks for the responses AP. Engine runs smoothly. As far as i know the inlet piping is all hooked up, but i guess its potentially incorrect considering the engine conversion. I might look over it tomorrow morning.

Stupid question but can a leaking head gasket even make a noise audible over exhaust, engine noise etc? To be honest the potential of a head gasket problem is the only reason i care about the noise, if i can rule that out then i'm happy to live with it.

Jack your car up (make sure its not going anywhere), start it up in neutral, climb underneath it, have someone stuff a rag up the exhaust, slide around under the car and double check for exhaust leaks by ear and feel - you'll feel the gasses coming out if its a small leak but hear it if it a decent size leak.