Strange noise poss from gearbox or diff

apole · Post by **apole** » Thu Dec 06, 2007 12:05 pm

Hi,

Noticing the start of a strange noise, not very load but it happens between 2 and 3000RPM. It sounds like a fan belt slipping but much quieter and seems to happen only when accelerating not once you are up to speed.

From the drivers seat is seems to be behind you (like back of engine not rear of car).

Any ideas what this could be, maybe diff, torque converter?

Thanks.

Harry · Post by **Harry** » Thu Dec 06, 2007 12:36 pm

As with other strange noise topic....check your manifold Studs.

Number 1 stud is famous (infamous) for shearing and producing strange whining noises

H

Veg_Ian · Post by **Veg_Ian** » Thu Dec 06, 2007 1:44 pm

Apole

strange that this should manifest itself after the LPG conversion. Maybe they didn't tighten something down properly? I would inform the LPG mechs and see if they are prepared to investigate the source of the noise for you.

mikeonb4c · Post by **mikeonb4c** » Thu Dec 06, 2007 2:10 pm

I gather the Bongo V6 is a quiet engine anyway (compared to the diesel Bongo). Is it quieter running LPG (when I hear LPG exhuast noise it always seems softer than petrol? Is it possible other noises have thus become more noticeable? And is it possible that accelerating the engine when its running on LPG produces some different characteristic in the engine noise (maybe to do with inlet vacuum and/or lack of atomised liquid petrol).

I have on idea whether the above is complete rubbish (probably is). But the questions above seem reasonable 'devils advocate ' ones to ask.

Keep us posted - sounds interesting (literally!)

Mike

apole · Post by **apole** » Thu Dec 06, 2007 2:39 pm

Hi,

Good points. I can tell a little difference so far on petrol or lpg in terms of noise or smoothness. It seems a bit fainter on lpg in terms of noise. I did flick between the 2 when I noticed the noise I was worried about and that didn't make any difference.

Just had a good look at the installation, looks neat. Had a good listen as well, couldn't hear any leaks.

Like most noises I guess it's very hard to describe. It happens between 1500 and 1800 rpm when the engine is under load and it sounds like a very faint slipping fan belt.

I was a bit concerned on the manifold as I think that would have been something they took off when it was installed, however I can get close to both sides and it is very quiet.

Maybe it's just me, havent' driven it for a while, it all works very well so far.

Weird that you notice no difference, even when it switches over, not sure what I was expecting mind and a few longer journeys will be more telling I guess as I've only done about 20 miles since I had it back.

mikeonb4c · Post by **mikeonb4c** » Thu Dec 06, 2007 2:57 pm

You may be having an attack of BOA (Bongo Owners Angst). Many new owners suffer an attack of it, but the condition usually abates quickly. It has been known to erupt again, usually after exposure to rising fuel prices. But like rich food, the best treatment is usually to continue to eat it but less often, rather than risk depression by cutting it out altogether.

apole · Post by **apole** » Thu Dec 06, 2007 2:59 pm

If I had too much rich food I could provide the gas myself !!

mikeonb4c · Post by **mikeonb4c** » Thu Dec 06, 2007 5:43 pm

apole wrote:If I had too much rich food I could provide the gas myself !!

We'll make a lateral thinker of you yet. All you need is an enema tube, a plug in point in the drivers seat, a valve system allowing switchover from LPG to HPG (sometimes known as HFG) and a diet of baked beans and cabbage

apole · Post by **apole** » Thu Dec 06, 2007 5:55 pm

mikeonb4c · Post by **mikeonb4c** » Thu Dec 06, 2007 6:39 pm

Looks like old apole didn't take our advice 'bout them reeeeversin' sensor thingamebobs there Cleetus. Reckon he just reeeeversed into the garage and caused a spark or somesuch

apole · Post by **apole** » Fri Dec 07, 2007 2:38 pm

LOL

I did some more checking before the spark incident and the noise is actually air being sucked in, you can hear it quite clearly if you are sitting in the passenger seat, kind of at the back of the console.

I will check all the pipework over the weekend to see if anything is loose.

Maybe they did cater for the potential to add a second gas supply after all....