Quote:
Originally Posted by Jimarilo
A strange thing happened this morning coming home during a leisurely drive Slowed down to turn left at a junction and all of a sudden heard a loud top end tapping, sounded like a camshaft. I immediately pulled in and checked under the bonnet, checked the oil level etc, everything seemed ok. Started it again and revved up the engine a couple of times, still the same. Turned it off and wondered what my options were and decided to see if I could make it home. I started it up again and no noise, which makes me wonder if it had something to do with the vacuum pump and follower. I had to remove it to fit the short dial gauge extension when timing the pump
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Quote:
Originally Posted by BogfordGarage
Apparently the Vacuum pumps can be responsible for a lot of noise when on their way out on these engines. I doubt you did something wrong. I did read somewhere if you take the diaphragm out and flip it round it can work to stop noise. But if it needs replacing make sure it's an original Pierburg branded one as the aftermarket ones can leak oil. If it happens again try the old solid bar or screwdriver test to narrow down where the noise is coming from.
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Yes agreed, very common to see this kind of noise from the vac pump, and it is often intermittent also as you described. I have never been too sure of what exactly goes wrong with them but I think either a check valve sticks or the return spring gets weak... either way it can let a clearance open up between the cam and pushrod resulting in a tapping noise. You can confirm it by running the engine with the vac pump pushrod removed. But it sounds like you are already all figured out on that.
