hydraulic tappets & engine flush????

My car STILL makes noises like an metallic woodpecker. It has just had MOT,
annual service inc filters, oil etc. Guy said that the noise was the
hydraulic tappets with an oil flow problem and that the new oil change and
better quality Castrol oil(!) should solve the problem. It hasn't.... He
also said that at 85k miles it would cause more problems than it would solve
to flush the engine oil out as the bits in the system would be moved around
and might cause a problem elsewhere rather than at the bottom of the sump.
Volvo 400, 14 years old, 1.7 engine with 85k on the clock

Is he right? Are the manky bits best left where they are?
Is the problem of the hydraulic tappets noise going to result in broken bits
in the engine if I just let it keep rattling away?

Info from earlier posting.............
It only happens when car is very cold. Usually after 1/4 mile. I have used
one of those valve cleaner type liquids - you know, warm engine - pour 50ml
into each plug hole, leave for 20 mins, cover/fill holes with cloths, turn
engine for 10 secs and cover yerself with oil and then drive for 3 miles
with a wall of smoke behind you (only joking with the last bit). Once warm
the car is fine and the noise only happens for a hundred yards or so.

 

Latest info from Volvo site suggests that:-
the petrol engines used in the 440 series don't have hydraulic tappets
(according to my Haynes manual). They use inverted bucket tappets with a
shim (might be called a biscuit?) to set the valve clearance. Clearance is
adjusted by using shims of different thickness. One advantage of this system
is it does not tend to go out of adjustment. I think it unlikely the noise
is associated with the valvegear.
To get at them it would be a manifold and gasket removal job, and it was
then a very very fiddly job replacing them.

any further thoughts appreciated folks.

 

You sure it's tappets & not just piston slap?

 

So, the noise goes away after a short period? I wouldn't be worrying about
it. Sounds pretty normal to me.

Cheers
Hammo

 

Noisy tappets never hurt any engine.

If the noise goes away when hot, I'd cease worrying.

I've not found any way of curing permanently noisy tappets apart from
replacement.

 

Sound advice IMO. I've never been an advocate of flushing oils
for the very reason mentioned.

Although from your later post the engine has buckets and shims.
That doesn't guarantee that the noise doesn't come from the
valve gear.
Wear on the camshaft, buckets or shims could still have made the
valve clearance a little excessive. Enough to make them a little
noisy.
If you can live with it the chances of it developing into
something more serious, or breaking something, is highly
unlikely. A car can do many thousands of miles with noisy
tappets, without causing any real harm to the engine.
Only if it gets worse, and starts to affect performance should
you think of getting it fixed. At that point it might be better
to consider getting rid of the car, as unless you do it
yourself, it'll almost certainly cost more than the car is worth
to fix it.
Mike.

 

Mad Sad Dad let forth with a mighty belch and uttered :

<snip lots>

Hold on a mo.

Bucket+shim not need adjustment?. true they do stay in adjustment for
longer, but not need adjustment?, I'd dispute that. If the valves recess
into the head, the gaps close up. The engine tends to get a little quieter
initially, then it loses compression and burns the valves. For them to get
noisy and tappety, the clearance must have increased. This points to wear
in either the cam face or the bucket if they are inverted, or the shim if
shim over bucket.

That it quietens upon the engine warming suggests that expansion in some
component is taking up clearance -or- its taking some time for an oil
cushion to form.

Sufficient wear in the cam face/shim/bucket to be audible would not be
likely to go away completely so quickly. Could do, I guess, but not likely.

Next up, oil feed to the cam, ie, is the guy certain that the oil feed is
adequate. If the cam is oil starved, it'd make a bit of a rattle, but not
usually for so long unless it was in serious trouble.

One thing that is not in dispute is that flushing a highish mileage engine
is likely to dislodge crud and cause more problems than it solves.

Does the HBOL for this car specify a check interval for the valve train?


--

 

Yes. If you flush the engine you will probably end up with just gunk
blocking the inlet holes to the hydraulic tappets. Then they really will be
buggered.

Well that's absolutely normal. What has happened is that whilst the car has
been standing, a small amount of oil has seeped fromt he tappets, hence they
become a little slack and rattle. When the engine has warmed a little, oil
is able to flow into the tappets and they take up the slack.
As for valve cleaner, that will have no effect upon the tappets.

Behaviour like this is totally normal for an engine of that age. AS long as
you don't thrash the heck out of it before it's fully warm and quiet, it's
no problem.

Robert

 

If you've ever had anything to do with Astravan turbodiesels you get to know all about adjusting bucket & shim tappets

 

A local mechanic said yesterday in an email to me:-
The old VFRs changed from screw adjustment to bucket & shim and what they
say is all true to an extent, however, new good oil should make it
noticeably quieter, even if it was so far out that it didn't disappear. If
it doesn't, it could be a broken shim (unlikely) or side lash in the rocker
arm due to wear (very possible). its another of those " is it worth throwing
another 200 quid at" jobs.

Before I go and chat to him ...

What does VFR mean?

Is "side lash in the rocker arm" painful or worth repairing??

 

I can't help you with your car problem, but...

I think he's referring to Honda motorcycles with VFR, which I believe
stands for Vee Four Racing. I know the first versions of those bikes
had camshafts that were referred to as, "Made of chocolate" they were so
soft and wore out so quickly.