Thanks Dennis, this was surprising to me but I trust your judgement.

One thing not mentioned is a time element in oil change interval. Is time a factor at all? I don't put on 7500 miles in a year, maybe not in two years these days.

-Mark

> On May 15, 2024, at 4:15 PM, Dennis Haynes <d23haynes57@HOTMAIL.COM> wrote:
> 
> If you read the owner's manual, even back then the recommendation for both conventional and synthetic oil was 7,500 miles. For Fun Bus, while I did ad an oil cooler almost immediately after purchase I have been on a 7,500 mile interval, most of the time. Using Mobil 1 15w-50 or for the last few years 5w-50 for winter. At 354K the engine, head gaskets and all have outlasted 2 transmissions and the rear chassis. It is off the road due to separation of the right side rear trailing arm mount. 
> 
> For my 91 van that I acquired 5 years ago, at 248K the engine had heads replaced at 168K and had a burned valve when I got it at 248K. I replaced the 1 vleve, tossed in a set of rings for good measure, now has over 300K and running strong. With a GoWesty oil pump and yes an oil cooler it still holds excellent oil pressure usually about 45 psi highway speed, 10-15 idling.  
> 
> Anyway, to really determine how often oil needs to be changed you need to do analysis. For the Vanagon, the end of oil life was usually nitration, at about 7,500 miles when I used to do testing. From experience with other Vanagons coolant contamination would sometimes be found. The Vanagon cylinder materials and with a properly working fuel system wear and fuel contamination is not really a problem. 
> 
> And even if not using a "synthetic" conventional oil is much better today than it was in the 80's. 
> 
> Dennis
> 
> 
> -----Original Message-----
> From: Vanagon Mailing List <vanagon@gerry.vanagon.com> On Behalf Of Dan N
> Sent: Wednesday, May 15, 2024 11:38 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Oil change interval
> 
> Hi All...
> 
> For a 2.1 WBX... 30+ years ago recommended oil change interval was 3K to 4K miles. Since oil quality/composition evolved, is it safe to do oil changes at 8K to 10K miles? This is using Conventional Oil (not Synthetic).
> 
> Thank you..
> 
> dan