Date:         Tue, 2 Apr 1996 23:15:29 -0700
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         stirling@rof.net (James Cohen)
Subject:      Re: 68: What is this damnable noise???

Duuuhhh, it sure sounds like the main bearings to me.  That is EXACTLY  the
sound that they make (and so described by Muir).  The-as you say-purported
life of the engine may not be accurate.  Or, the last "rebuild" only
included the top end.  New rings and a valve job.  If it is the mains,
you'll see the oil light flicker eventually but there may not be any tell
tale signs at first.  If the engine eventually overheats and seizes, thats
what it was.

A better possibility (and cheaper) is air leak into the passenger
compartment.  If air rushes in (like through the sunroof) it will belch out
through the same opening in a deep resonance.

Another possiblity ( and even more scary) is the ring and pinion gears of
the trans.  Once again deep sounds but no real symptoms until it's too
late.

Just my diagnosis.

James
'67 deluxe
'71,81,'85 Westies




>Some experienced person please help with this. It's about to drive me bonkers:
>
>This noise is new. It showed up all at once.
>
>The noise is low-frequency and it reverberates throughout the bus. I can't
>tell where it's coming from, it depends which way I turn my head.  The
>noise begins precisely at 43 miles per hour, and increases in frequency and
>volume the faster the bus goes. It doesn't grind; it's somewhere between a
>hum and a sustained moan. There is a vibration to it but the vibration is
>tactile, not aural; you can only feel it.
>
>If this noise was coming from a musical instrument, it would be a double
>bass playing a sustained note with a bow. Midrange (for a bass). It's a bit
>like riding in a large passenger aircraft and sitting on the wing, but
>without the whine and whistle. Get it? Like a low, smooth, sustained
>head-buzz. Though it sounds *very* much like a sympathetic vibration, it
>does not throb at any speed, nor does it disappear at any speed above 43.
>
>The noise disappears entirely when the bus is taking curves. It only
>happens on straights.
>
>The noise does not care a bit about engine speed. Doesn't matter whether
>I'm in fourth or third. But I can make it cycle with the accelerator,
>putting it under load and backing off. It's much louder under load.
>
>I replaced the right rear wheel bearings. If I had to guess, I'd say it's
>coming from the rear, and the right wheel had lots of play in it. Lovely
>new FAG bearings and seals with lots of slippery grease. Took five hours.
>The noise perseveres.
>
>The CVs seem fine. Boots tight, no clicking in corners.
>
>Today I had the trans oil changed. I do believe this trans is elderly; the
>syncros are balky and it has its bitching and moaning routine that it must
>do when warming up. But it has never yet popped out of gear. Changing the
>lube made no difference in the noise whatsoever. The old oil was not low,
>there was plenty of it. No chunks came out that I could see. No shavings
>stuck to the plug.
>
>The day before the noise came to town, I had adjusted all the brake shoes
>and the parking brake. The cables are old and slack and I could not
>possibly have locked the parking brake on even if I didn't know what I was
>doing. None of the shoes are locked on. None of the hubs are hot when I
>stop. Transmission isn't hot, either.
>
>There is no reason to believe that it is main bearings. This engine is
>reputed to be nearly new, there are no oil pressure problems, the bus uses
>no oil and has no leaks at all. Good power, good mileage, no smoke. Just
>passed emissions.
>
>There are no symptoms other than aural ones (and no jokes from the
>vanagon@lenti wags)(as if I expected that to stop you) and the dimly-felt
>vibration. But this noise is *loud*.
>
>This has got to be somewhere between the front of the cranshaft and the
>tire rubber. What in the hell is it?
>
>--Ken
>  '71 Bus, '68 Westy

'67 deluxe
'71,81,'85 Westies