Air whooosing sound and air from round spark plug, help

[Johnmck]

Hi got CU air cooled engine, got a new strange sound and air coming out of tinware around cylinder 4,lefthand side nearest bumper. Hadn,t noticed before but cleaned plugs and started up and noticed it. If i put my hand over hole round where spark plug goes in i can feel a strong jet of air and the sound is like an airline noise. What is going on?? engine runs ok but afriad to chance it! supposed to be going to skye at weekend. Any ideas???
Thanks

[VWCamperfan]

Probably just air coming out from the cooling fan. If you have the correct plug leads then they seal the hole around the plug. If you don't then you will get some air pushing past.

[orangebooboobearcrew]

Hi,

Are you sure you have tightened the spark plug up properly when you put it back in the hole?

Wooshing sound is probably just the compression in the cylinder created by the piston moving upwards which is how an engine works. If you haven't tightened the plugs properly, the air will escape past them creating this sound...

[Johnmck]

thanks re seated and tightened spark plug still the same, gap round the plug in tin ware is a bit ragged, but have never had the sound and air flow before. You can hear it over the engine tickin over

[billy739]

have a look at the smaller pipe on the manifold , rubber junction , these can perish and leak air, put your hand round it, wobble it when engine running see if it makes a difference!

[Johnmck]

thanks , where about do you mean?

[jason k]

the rubber elbow on the inlet manifold.

[billy739]

on the cast manifold below the carb , above the sparkplug holes!

they can tear/perish or just come adrift if touched!

[Johnmck]

Hi, been away, had another go tonight, the air is coming up through all the plug holes in the tin ware- it moves the little rubber caps. I assume it is something to do with the cooling fan?
Is the normal outlet for this air blocked? and why the noise, never heard it before and it is loud on tick over so it drownds out the normal tick over noise.

Any ideas?
is it safe to drive?

[VWCamperfan]

Yeah, it's safe to drive. Just to be sure, start engine and slide under back of van. Feel for air flow from rear of engine under cylinders. Should have plenty.
There's quite a lot of air being pushed through the tinware and it'll try to find any excuse for a way out... In your case it's the spark plug holes!