I'll post this, due to the pressure switches stuff, though most of the 
other replies already covered the essentials.

Begin forwarded message:

> From: kimbrennan@mac.com
> Date: Wed Jun 19, 2002  01:14:55 PM US/Eastern
> To: "A. Widoff" <rompu@MHCABLE.COM>
> Subject: Re: 87 Vanagon problem
>
> On Wednesday, June 19, 2002, at 11:55 AM, A. Widoff wrote:
>
>> I feel like I might be doing damage to my vehicle by continuing to 
>> drive it,
>> but my mechanic doesn�t see anything wrong with it.  Any insights into 
>> this
>> would be greatly appreciated.
>>
>
> There are two types of oil to put in a Vanagon. Straight 30 weight, or 
> 20w50...unless you are in very cold climates.
>
> If you use 10w30, the oil pressure light (and buzzer) >WILL< come on 
> once the engine heats up. 10w30...and 10w40 are simply too light a 
> weight oil for the engine, especially in the summer time.
>
> Additionally, if you aren't using the OEM oil filters, it is possible 
> that you aren't maintaining the correct oil pressure.
>
> Finally, it is possible that your oil pressure switch(es) are bad. On 
> non-Syncro models, I believe there is only one oil pressure switch. 
> Syncro models have two. I had one of them fail last year.
>