Date: Fri, 14 Sep 2012 23:42:45 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: [Diesel-Vanagon] Re: Oil temp gauges,
choices? Using water temp sender + gauge?
In-Reply-To: <1347646667.95088.YahooMailNeo@web163401.mail.gq1.yahoo.com>
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The plastic VDO gauges just aren't what they used to be. Luckily engine and
road vibration will take that "stickiness" right out.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Poppie Jagersand
Sent: Friday, September 14, 2012 2:18 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: [Diesel-Vanagon] Re: Oil temp gauges, choices? Using water temp
sender + gauge?
Mark,
Thanks for doing the testing. It shows that it is possible to get a
reasonable sender - gauge pairing.
I was curious if you or anyone else noticed the sticky needle issue I had?
It is easiest to see when instead of the sender one used a potentiometer
(variable resistance) anything around 100-200Ohm is suitable.
To see if it the gauge needle is sticky 1. turn the pot up to near full
gauge 2. Then slowly turn down until needle is over a reading (say 260F).
3. Now disconnect wire between pot and gauge. gauge falls to 0. (do not
change pot) 4. reconnect wire. See if gauge shows same reading (260F).
If the needle is sticky it will show a smaller value. For me the value at
step 4 was 10-20F below.
Same test can be done with regular sensor in water + using a digital
meat/bbq thermometer as reference.
First slowly heat the water to boiling.
When VDO gauge reaches each of 120F, 180F mark read the digital temp
Then let the water cool. Again read digital temp when VDO gauge reaches each
of 120F, 180F.
Ideally temps should be same, but with a sticky needle they may differ
Using canola oil instead of water one can test the 220 and above readings
too.
Martin
________________________________
From: mark drillock <mdrillock@COX.NET>
For fun I just now tested 3 VDO temp gauges and senders I have on hand.
I used a 12 volt battery and a pot of boiling water, at sea level.
The first was a new VDO aftermarket water temp gauge 0-250 F. It was paired
with the aftermarket VDO brand temp sender of the matching range, sold to me
at the same time as I purchased the gauge.
With the sender in rapidly boiling water the gauge read almost exactly
between the marks for 200 and 225 F. A whisker higher than the midpoint,
maybe 215 F? Pretty good I'd say.
Next I grabbed a used VW car oil temp gauge made by VDO and the VW sender I
pulled from the same car when I pulled the gauge. Both are marked 0-150 C.
The sender has the same part number marked on it as the one you linked to
from TBD.
With the sender in rapidly boiling water the gauge read almost exactly at
the 100 C mark, just a whisker below, 98/99? Pretty good again.
Especially for parts pulled from a 25 year old car, with date codes on the
parts indicating they are really that old.
The third set didn't act right. This used 150 C VW car oil temp gauge read
very low when paired with the VDO sender I had it stored with. I then
connected up the sender from the other VW VDO setup and the gauge now read
correctly, near 100 C. Then I got out the magnifying glass and looked more
closely at the odd reading sender. It said 180 C on it, so no reason to
expect it should work right with a 0-150 C gauge. The VW part number on it
had a B suffix, rather than the A of the 150 C sender.
The rest of the number was the same.
I wanted to test some more but my wife was headed home and used car parts
are not welcomed in the kitchen when she is there too.
Mark
Dennis Haynes wrote:
> In dash gauges are not high precision devices. I have found that the
> for the VDO gauges the senders for the aftermarket gauges often do not
> match what is used for OEM gauges. Get the correct sender that would
> be sold with/for the gauge you are using.
>
>