Knocking/rattling engine noise

[stocktake]

Sounds very much like the belt tensioner. If the belts were last changed in 2010 then they are way overdue according to service schedule. I wouldn't be driving / starting the car unless absolutely necessary until they are checked.

[sean75]

Although the belts were last done in 2010 along with the tensioner, idler and water pump, the car had only done approximately 3000 miles in the period between then and now. It’s possible or more likely probable that the tensioner and or idler is at fault and also the water pump. Either way the belts will be changed next week along with all the other items that are driven by them. The reason I returned with the problem was because I know that it could end in engine death if it was to affect the timing .

I spoke again with my mechanic and he still has a (less convinced) theory that the inlet manifold is the issue , however we discussed the absence of T4 error codes, and the rapidity of the onset of the noise. He also agreed about the location and bearing type noise rather than clicking plastic at the top of the engine.
We’ll see what next week brings.

[stocktake]

Belts, pump, tensioner and idler are out of service time of 6yr by some margin.

To check inlet manifold is simple:

Remove power vis (the one on the top) it's a simple electrical plug and four screws and off it comes.
Look into the hole it came out of and you will see a brown arm with a slot in it, this arm should move side to side and be free but firm in movement.

Any up and down movement other than flexing of the arm is wear. For the butterflies to be making such a racket the arm would have to be detached from the butterflies to allow them to be swinging and rattling about, it would be very evident on this test if this was the case. Do not start the engine whilst carrying out this check.
Costs nothing to check for this fault .

[SD1too]

Originally Posted by sean75

... the car had only done approximately 3000 miles in the period between then and now. It’s possible or more likely probable that the tensioner and or idler is at fault and also the water pump.

I'd say that it's virtually inconceivable that a properly fitted tensioner, idler wheel or water pump would fail after as little as 3,000 miles. Timing belts attract fear and irrational diagnoses. There's going to be zero wear after 3,000 miles irrespective of the number of years that has elapsed. Mine were in immaculate condition after 90,000 miles and 18 years! Think carefully about that evidence.

Originally Posted by sean75

I spoke again with my mechanic and he still has a (less convinced) theory that the inlet manifold is the issue , however we discussed the absence of T4 error codes, and the rapidity of the onset of the noise.

I have heard manifold chamber rattle. It is continuous, loud and very alarming. The noise is the result of a worn valve linkage so if the actuator is o.k. you wouldn't expect a fault code on T4.
Why do you think that a rapid onset of the noise points to belts rather than anything else?

Simon

[sworks]

Stocktake gives good advice, carry out the checks to rule out the manifold. Next, I’d remove the auxiliary belt and run the car without it, this will rule out all the external jockey wheels. If the noise has gone spin them by hand to listen to any noises, I recently had an auxiliary belt tensioner fail on a car and it sounded more cambelt related but wasn’t thankfully. Finally. Don’t assume the cambelt and all aspects of it are good because the car has only covered 3,000 miles as the due date has lapsed. It’s easy for diy mechanics to say it’s absolutely fine as they won’t have the repair bill if it fails and manufacturers have intervals for a reason. Just because one person got lucky doesn’t mean it’s the correct approach.

[dave lincs]

Originally Posted by SD1too

I'd say that it's virtually inconceivable that a properly fitted tensioner, idler wheel or water pump would fail after as little as 3,000 miles. Timing belts attract fear and irrational diagnoses. There's going to be zero wear after 3,000 miles irrespective of the number of years that has elapsed. Mine were in immaculate condition after 90,000 miles and 18 years! Think carefully about that evidence.

I have heard manifold chamber rattle. It is continuous, loud and very alarming. The noise is the result of a worn valve linkage so if the actuator is o.k. you wouldn't expect a fault code on T4.
Why do you think that a rapid onset of the noise points to belts rather than anything else?

Simon

Simon

Sounds like the same old story repeating its self yet again can you please remind me of the belt change interval please? The op has said the car has been stood for 5 years do things not deteriorate stood still? If you say it is not a belt or tensioner issue and it proves that it is and fails will stump up the belt/tensioner failure repair cost, It is quite Simple Simon the reccomend belt change interval is 6 years or 90,000 miles

Dave

[sean75]

Not intending to start a debate about belt life vs intervals. I fully intend to have the belts , tensioner, idler and water pump changed as I said previously. I originally intended getting this done next year , that’s now been brought forward by the recent issues.

My reason for suspecting a component associated with the cam belt is the type if noise ,metallic and rhythmic, rising and falling with engine revs and the origin of the noise in the engine which is in the vicinity of the cam belt run and lower than the location of the inlet manifold. Obviously until the engine is stripped of the belts the true culprit will not be apparent but at over £1000 for a new inlet manifold I need to be absolutely sure it isn’t anything else potentially more serious.

Everyone is entitled to their own opinion and I genuinely value the different perspectives that come from reasoned debate especially that supported by evidenced experiences.

Please, let’s not begin a dispute with each other, it’s only a car after all and I am probably reaping the reward for its lack of use .

I’ll post more when I know.

Thanks

[Teflon]

Does it sound anything like this:



Noise starts around 19 seconds in, and quickly fades as the engine warms.

Cliff

[sean75]

Originally Posted by Teflon

Does it sound anything like this:



Noise starts around 19 seconds in, and quickly fades as the engine warms.

Cliff

It's difficult to compare really, the noise in your video is quite similar albeit less metallic but the main differences are the apparent location of the noise, yours seems to be from the top left (standing at the front of the car) and the fact that it disappears when the engine warms up and quite quickly too, its also not as loud and mine was evident from inside the car whilst driving and with all the windows and A/C switched on. Mine didn't do this and rattling was evident from initial start up to after the engine was at operating temperature.
Outside with the bonnet up and engine running it was the loudest noise i've heard this car make in 23 years of ownership and that includes the rattling that was present when I got the car, eventually rectified when the belts and ancillaries were last changed.

For those that have had definite inlet manifold issues, did the problem begin suddenly overnight- as mine has or was it a more transient deterioration?

I know the manifold problem won't kill the engine but a faulty tensioner or idler or waterpump will and whilst it's being inspected for this it just seems sensible to change the belts etc.

Thanks Cliff for taking the time to post the video, very useful .

Sean

[SD1too]

Originally Posted by sean75

Not intending to start a debate about belt life vs intervals.

Everyone is entitled to their own opinion and I genuinely value the different perspectives that come from reasoned debate especially that supported by evidenced experiences.

Please, let’s not begin a dispute with each other ...

Absolutely Sean, thanks for your very sensible post.

There's no point in speculation, let's see what the garage finds starting with the manifold chamber linkage and ancillary belt as previously stated.

Simon