Knocking noise whilst idling

[Flyingchunk]

Hi all

Just got my van running after 9 months (actually a mech did it!).

He is a little concerned about a knocking noise that the engine makes whilst idling.

It disappears when you apply throttle.

Any ideas?

Thinking out loud, my old 3 series used to do sonething similar if I'd not topped it up with oil.

Could this be it?

At work, so can't check oil at moment.

[pionte]

if it not been running for 9 months then it could just be that the oil has seeped out of the hydraulic lifters, mine does this after 3 or 4 weeks of none use... does it sound like a ball bearing in a tin can ? If this is what has happened then a good run will sort it out... 20 mins or so at high ish rpm.

It wont do any harm .

after refitting my engine mine was really noisy but came back up all ok after running on the drive and bleeding the rad.

[Ian Hulley]

Yep, tappet rattle.

* I'm guessing the mechanic's younger than the van ?

[Flyingchunk]

Phew!

That's great guys. I can breathe again.

It does sound like you describe.

The mech is also younger than the van (just).

He is a top bloke though, and mobile, which for busy non engine savy peeps like me with immobile campers (he has 3 on the go at the moment!) has proved invaluable.

[itchyfeet]

Go and give it a good run with some high revs then see if it's still there.

[California Dreamin]

And...we mean a good run, not 5 minutes around the block.

20 minutes, get it hot and give it some revs after 5 minutes.

Martin

[Chunksta]

What happens if a lifter fails and how do you spot when it is going to happen?

[pionte]

ive never heard of one failing.... guess that maybe they can but rare imho. If they did they would sound just like yours ! , poor engine performance and mpg too.

[Flyingchunk]

I've given its couple of good runs.

It still seems to be there.

I'd describe it as a clack clack clack, that eminates from down the centre of the engine.

Someone took aloof yesterday who apparently knows about these engines, and said it sounds "wrong", and if he didn't know better he guessed the engine was on its way out.

Obviously now I'm bricking it!!!!

[Ian Hulley]

I've given its couple of good runs.

It still seems to be there.

I'd describe it as a clack clack clack, that eminates from down the centre of the engine.

Someone took aloof yesterday who apparently knows about these engines, and said it sounds "wrong", and if he didn't know better he guessed the engine was on its way out.

Obviously now I'm bricking it!!!!

Why would an engine that was fine when it was parked up 9 months later be knackered ? By far the most common thing is for the tappets to drain down. Have you tried changing the oil and filter ?

Ian

[kevtherev]

What happens if a lifter fails and how do you spot when it is going to happen?

when a lifter fails it will not pump up despite all efforts to quieten it down
prolonged use of the engine in this state will see the rocker arm beat the valve stem to death

[tobydog]

http://www.wynnoil.co.uk/products-wynns ... lifter.htm" onclick="window.open(this.href);return false;

Used it once and it did the job. Would change the oil after a short while after use.

[Flyingchunk]

I've got no history with the engine whatsoever.

It hadn't moved since I bought it. I've been refurbishing it for our use, as it was uninhabitable due to the interior DISINTERGATING on touch.

Stupidly I ignored the engine, and not being an expert thought it just was the sound of it.

I've got it booked in with an expert on Wednesday, as it failed the MOT on emissions and I want to be cast iron on the engines condition.

I'm sure you guys are right as you're far more experienced than I.

Worst case scenario.... New engine... Gives me a chance to take the old one apart.

Lifters could be the issue. I'll let you know the diagnosis from the expert once he's looked at it.