Date: Tue, 9 Aug 2011 15:19:43 -0700
Reply-To: Karl Wolz <wolzphoto@Q.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Karl Wolz <wolzphoto@Q.COM>
Subject: Re: Oil level vs temp test
In-Reply-To: <4E41A70A.9040908@gmail.com>
Content-Type: text/plain; charset="US-ASCII"
Keep in mind that the dipstick is an approsimation, kinda like the fuel
guage, and it is common for our vans to have the wrong dipstick, leading to
a bit less accuracy.
The statement, "one should see lower oil temp if the oil level was kept
below the halfway point between the two notches on the dipstick" is not
quite accurate (not arguing with your quoting ability). I would argue for,
"one MAY see ..."
With the crankcase overfilled, the crankshaft hitting the top surface of the
oil pooled in the crankcase will whip air into the oil, kinda like whipping
cream. If the oil is filled with tiny bubbles of air, it tends to not be
able to lose heat, as the air is an insulator, thus causing the oil to get
continually warmer. The theory is that if your oil is running warmer than
expected, the problem may be an overfilled crankcase. Since you have
observed no difference after draining a pint, you are most likely not
getting "froth" in your oil.
You have my permission to add that pint back; the more oil, the better, so
long as you don't have too much oil!
Karl Wolz
|-----Original Message-----
|From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com]
|On Behalf Of Rocket J Squirrel
|Sent: Tuesday, August 09, 2011 2:31 PM
|To: vanagon@GERRY.VANAGON.COM
|Subject: Oil level vs temp test
|
|A couple weeks ago it was mentioned here that one should see
|lower oil temp if the oil level was kept below the halfway
|point between the two notches on the dipstick.
|
|Last weekend Mrs Squirrel and I went camping in our nearby
|National Forest. The drive that-a-ways saw oil temp rise from
|what appears to be "cruising" temp of around 190 degrees (F)
|to about 215 on the steep bits where I had to downshift to
|second gear (auto trans).
|
|Ambient temp was in the mid-80s, and the oil level was 3/4's
|up from the bottom notch to the top notch, or halfway between
|the halfway point and the max point.
|
|So this morning I lowered the oil level to the 1/4 point
|(halfway between the min notch and the halfway point between
|the notches) and have just now returned from the same drive,
|or at least the portion of it where I saw my first temp rise
|on the last drive. This is a 14 mile drive with an 1800 foot
|elevation gain. Like on the previous drive, I kept the engine
|to 3600 rpm in second gear on the steep bits. Today's temp is
|in the mid-80s.
|
|I saw no difference: from "cruising" temp of 190F, the oil
|temp again rose again to around 215.
|
|Perhaps a longer drive or one under different conditions might
|show the predicted improvement in oil temp.
|
|--
|Jack "Rocket j Squirrel" Elliott
|Bend, Ore.
|1984 Westfalia. A poor but proud people.
|1971 "Ladybug"-brand utility trailer from a defunct company in
|San Clemente, Calif., now repurposed as The Westralia.
|
|Sent from my kitchen.
|-----
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|08/09/11
| 
