knocking rattle on accelerating

[ElmoEldridge]

Our Bongo is making a worrying noise and we have had no luck with our mechanic figuring out what it is, so we thought we'd describe it and see if anyone has any ideas.

It happens during acceleration, especially when pulling out from a stop, and is more pronounced the harder the accelerator is pressed. It's a rattling noise, quite loud when the windows are open, but still very noticeable when they're shut. It sounds like a metallic rattle, definitely connected with how hard the engine is working. We thought is might be the engine itself, but our mechanic says that is fine. The mechanic thought maybe driveshaft, but he says that isn't what it is. Then he said something about a "flexi drive plate" but that requires taking the gearbox out first. Any other ideas, before we get our mechanic to start dismanteling?

[missfixit70]

Is it more speed related than revs related? Does it stop or lessen if the power is taken off? does it go away on braking? Worse on cornering? Difficult one to remotely diagnose that one, maybe if you could record the sound & put it on a hosting site & post the link?

[gmaczbongo]

Are you running diesel or veggie mix.
It could simply be a slight timing problem.
Is it smoking at all when you are accelerating.

[Tripewriter]

The timing should not be an issue unless someone has messed with the pump or the timing belt is slipping.



The symptoms you describe could indicate that insufficient fuel is entering the combustion chambers or just one of them( they clatter when empty), as it is when accelerating I would check the air filter. However it could also be caused by air being sucked into the fuel lines due to a flexible tube fuel failure, a loose connection on the injectors etc, worn injectors, contaminated fuel.

See if it makes the same noise when revved hard while stationary, try it when its cold and up to normal temperature.

Bongo diesels are old technology so younger mechanics may not have the ears for it.

Try to find a diesel specialist, a garage specialising in commercial vehicles is a good idea.

[mr ice]

Ask your mechanic to try rear driveshaft flexijoint as it may be ceasing up. I just changed mine and it had the same symptons. I bought a used one from bongobits.

[dandywarhol]

The "flexi plate" is the drive plate between the engine and the torque convertor - if it cracks it can make a metalic noise but I've never heard of one fail on a Bongo!

I'd go for a front crankshaft pulley beginning to fail - usually accompanied by a vibration. Check there's no free play in the pulley which drives the alternator belts, thats what I'm talking about

[popthebrick]

sounds like the same noise i had, it turned out to be the rear propshaft, could be worth checking.

[ElmoEldridge]

Thank you all for you replies. It was the rear propshaft after all. One of the universal joints had seized. This fooled our mechanic, because it wasn't loose as it would have been if the joint was falling apart. He told me that he has learnt something (which I think must be quite an achievement with a mechanical issue for a mechanic with over 30 years experiance.)

I am happy to report that our Bongo is up and running again and ready for a trip down to London on Friday.

Cheers
Elmo.
--
--Buxworth, Derbyshire

[BongOutBienMorts]

Is it more speed related than revs related? Does it stop or lessen if the power is taken off? does it go away on braking? Worse on cornering? Difficult one to remotely diagnose that one, maybe if you could record the sound & put it on a hosting site & post the link?

Hello - responding to an old thread here in desperation! Thinking I may have a similar issue..??

I've been asking on this thread: viewtopic.php?p=722334#p722325

The rattling noise happens strictly when accelerating: when revs are at approx 2300-2400RPM. Above and below that she purrs like a kitten (or rather; chugs like a tractor - but a happy one).

It's a rapid, high-pitched metallic ticking/clicking/clanking/rattle - a bit like somebody rapidly playing the triangle.

Seems to be coming from below on the front passenger side. - Video attached - (please excuse how short it is... my dad was on the accelerator and he is deaf as a post... - so it was a battle to get it at all...)

- Video was taken whilst stationary (in Park) from cold = makes the same noise when hot. It's been suggested that it could be a universal coupler on the drive shaft - but would that still make the noise if stationary>??

1995 2.5 AFT dual battery (Northern Japan Style),

Many thanks in advance for your thoughts, advice, and time.

Bing.