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MG MGF Technical - Engine Knocking/Tapping

Just had the AA to have a look at my 97 VVC as the knocking noise from the engine seems to be getting louder. They said it sounds like the tappets? This means nothing to me?

MG had a look, once when they did the 48k service & again two weeks ago & they couldn't find anything wrong. But they admit they could hear the noise.

Any ideas?
Gavin Evans

Gavin, any mechanical noise getting louder is likely to spell disaster, find out exactly what they have checked as VVC's of this era have a habit of dismantling themselves. Avoid driving it until you have it properly checked out preferably immediatly. If you still have problems get in touch.


If the AA say its tappets then I would be very suprised if it were anything else - Tappet noise is very easy to identify and means the engine is fine - maybe it requires a slightly different grade of oil and a good flush out before changing

Tappets push the valves in to allow fuel into the cylinders and exhaust gases out

In the rover the tappets are operated by oil pressure - on older cars this was done mechanically

So nowadays you dont need to adjust the tappet clearance as the oil pressure should take up any wear - however the oil galleries can get a little blocked so reducing oil pressure - so creating a small clearance that results in the tapping noise - Many cars do it !

There is no definate cure for this - but it wont harm your engine - its just irritating!

Try flushing the engine oil with a good cleaner and replacing with different oil = Do you know what oil its using at present ?

Tony, Thanks for the advice, MG changed the oil about 500miles ago when I got it serviced. It's currently got Shell Helix Plus 10w 40. I'll try the engine flush tomorrow, any specific engine flush? Also what oil should I put in then?

Mike, I'll try Tony's idea first, otherwise I'll take it to a different MG dealer to have a look.
Gavin Evans

A sunk down tappet gives more of a metalic clinking noise. It should clear in a few minutes. I hate to say it but your problem does sound more serious. I agree with the other writer, it sounds like one of your VVC units is on its way out - expensive.
Paul Hollingworth


Same problem with my '97 VVC - hydraulic lifter on #4 cylinder. Had changes in frequency which means the lifter was slowly revolving (used a stereoscope to pick this up). Had the local garage flushed the engine (I dont do oil changes anymore pain getting rid of the old oil) - new filter etc. Running Mobile 1. Noise is amplified due to the engine being shoehorned into a very tight compartment.

Up side of the engine flush was, a lower oil temperature and a slightly quieter lifter.

Still have the occasional miss fire even after I changed, the fuel filter, removed the fuel pump, checking suction pipe, replacing the HT leads and last week replacing the battery been working in Oz for the last 5 months battery had sulphated (lack of charging).

Next step to a local dealer and have TestBook perform diagnostics on the MEMS.
Dennis Montgomery

Thanks for all your advice guys, I took it to a different MGR dealer today. They found that it was acutally a spark plug that wasn't in correctly.

Ahh, I've got it back now, excellent. It even seems a little quicker off the mark. Maybe just me though.
Gavin Evans

Crappy, my car started tapping...
I think I am low in oil so filling it up at the moment. Hopefully that solves the problem..
Hanah Kim

This thread was discussed between 14/12/2001 and 19/12/2001

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