In the past a number of people who have oil temp gauges, and/or oil
pressure gauges, and tachometers have noted that right at 4,000 rpm
steady state driving, the oil temperature seems to significantly
increase.  When the oil temperature gets beyond a certain point, about
250 degrees, IIRC, the pressure is less and the protection of the engine
is therefore decreased.  Oil temperature is reported to be noticeably
lower at 3,600-3,800 rpm steady state driving.  This discussion has been
on both this list and on the Syncro list - perhaps more there than here.

As Bob Donalds noted, this does not refer the rpm's when you are
accelerating from a stop or in changes in stop and go driving, but
steady road driving.

Based on this many have recommended that you run your van at slightly
below 4,000 on the highway or any other steady state operation.  While I
used to drive my 84 over 70 consistently and thus well past 4,000 rpm
before learning about these concerns on the lists, I now rarely drive
beyond 3,800 rpm and then only for short distances, like passing, etc.
I also know that I am saving on gas mileage at the lower speeds.

However, I often go up to 4,500  or more when accelerating through traffic.

Sam

--
Sam Walters
Baltimore, MD

89 Syncro GL
85 Westy Weekender
84 Vanagon, original owner, soon to be retired, just too many problems

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