2.5 "tappety" sound on start up
 

My 2.5 75 had been off the road for circa 5 years before I bought it and I've spent another year doing multiple works to bring to roadworthy condition. I also changed the belts due to lack of history.
The car now runs really well, but on start up, and for the first couple of minutes idling, there is a tappety sound. This doesn't happen if the car has recently run.
It sounds to me as though there is reluctance for the oil to get up to them, but is this a known problem, (with solution?).
Oil level is correct.
Thanks,
Michael

Cliff (Teflon) had a similar sound and it turned out to be piston slap.

Here's what mine sounded like (noise starts around 19 seconds in):



Once the engine was warm, the noise vanished.

Cliff

Thanks both. That noise is similar but I think lower pitch than mine. I'll try and post a similar video. What's the prognosis for piston slap? is it curable?

Since I originally posted I found reference to a Rover bulletin, TB0037, advising a cure for noisy tapetts by changing an O ring on the oil pickup tube. I can't find original bulletin, but it seems the mod prevented air being drawn in at the joint and allowed the correct amount of oil to be drawn out of the sump.
Does anyone have any experience of this mod?

I believe piston slap is common on the KV6 and nothing to worry about. Just wait until the engine is up to temp before giving it the beans! My ZT does the same.

Hi Michael,

In my experience this could be one of four things.

1. Contaminated hydraulic tappets, particularly as the car has not been fully used for 6 years. One or two doses of Comma "Flush Out" is effective for this. This product is not added to your oil, it temporarily replaces it but with the car stationary at a fast idle only. After use, change the filter and refill with 10W40.
2. Cuts in the ancillary belt rubber. An inspection via the OSF wheelarch will reveal this.
3. Worn timing belt tensioner and/or idler pulleys. What was the mileage when you renewed the belts? It's hard to say when mine started being noisy but it was well after 50,000 miles.
4. A rattling power valve linkage in the manifold chamber.

If you've removed the engine sound-deadening cover to determine that the noise is without question the tappets, then proceed with using Flush Out.

Simon

Hi Michael
There was a bulletin about the o ring on the pick up pipe but from memory it was only a certain range of 2.0v6 engines I will try and find it and check, I would suspect from your description that it has got some piston slap this often happens on cars that get used on short trips with a lot of cold starts if that's what it is dont worry about it as when warm the noise will have gone

Dave

Thanks all for the responses. Much appreciated as always. As the car has had so little use for a prolonged period I'll look up the Comma flush-out. I've changed belts and tensioner.
If that doesn't change things then I think piston slap is a "feature" of my engine, as garages used to say, and probably still do!
I'll let you know for completeness of the post.
Thanks,
Michael.

If it helps, the piston slap on my KV6 was diagnosed by a mechanic using a long screwdriver as a "stethoscope" on the engine block :}.

My mechanic agreed with Bazzateer and Dave Lincs, and said it wasn't anything to worry about, however, being a fussy old so & so I had him fix it anyway :}

Cliff

Another source of tappet-like noise at tickover is the canister purge valve. Petrol models that have been out of service for a while will display this noise. Over time, and with some juice in the tank, the petrol vapour absorbtion canister (mounted under the rear end) becomes pretty well saturated and that gets cleared during tickover. My 1.8T has been SORN'd for some monrhs and every startup is presently accompanied by tapping from the purge valve - or 'slack tappet simulator' as I call it. This thing will tap away for hours if the engine's left running. Yours is mounted on the upper inlet mainfold (RHS as viewed) where the tapping is easy to hear. Disconnecting the power connector plug stops the tapping. It's a simple way of elimiating one common cause of 'tappet noise' and I suggest it every time I read about little used or SORN'd V6s with tappety engines. So, suck it and see.



TC