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Subject:Re: Coolant Temp Sensor Test. Generic vs VW.
From:Dave Mcneely
Date:Tue, 6 Oct 2009 09:30:39 -0400

My mechanic put a Jetta temperature sensor on my camper with 2.1 engine.
He said they were the same sensor.  Dave Mc

On Mon, Oct 5, 2009 at 9:31 PM, neil N wrote:

> Hi all.
>
> Temp/resistance graphs in my Vanagon and Mk3 Jetta Bentleys appear to
> be the same. Based upon that, it may be that the Mk3 Jetta and Vanagon
> sensors have the same specs. If so....
>
> My VanaJetta swap has had a long standing intermittent hard start
> issue when engine warm. Wasn't really a problem. But twice finding
> this engine error: "ECT - Intermittent Short to Ground", finally got
> me off my butt to check things out. Since I have the sensor that c/w
> engine (Possibly OEM? Has VW stamp. Made in Luxembourg), figured I'd
> test and compare it to the suspect no name sensor.
>
> Heated each in water, 70F to boiling I see ~ 600 to 23 ohm difference.
> (below)
>
> Ironically, since I chose to install a new one at time of swap, the
> "VW" sensor seems within spec. The newer suspect one doesn't, but is
> close. Since it was close.....
>
> Do the resistance value differences between the two sensors indicate
> manufacturing differences (possibly quality control) or is the No Name
> just a failing coolant temp sensor?
>
> Personally if the differences are due to lack of quality control, I'd
> be tempted to spend the $ at the dealership if an OEM part can be had.
>
> Neil.
>
> Test pics:
>
> http://picasaweb.google.com/tubaneil/ECTTesting#
>
> Results:
>
>
> On stove at "Med" to 80F, then "Max" to boil. At 212F for 1 min.
> Converted to Celcius. Water stirred until boiling. Ignore the decimal
> point!
>
>          No Name             VW
>
> 21C  2900  Ohms       2300 Ohms
> 27     2440                  1920
> 32     1940                  1550
> 38     1656                  1300
> 43     1360                  1070
> 49     1130                    890
> 54       932                    750
> 60       780                    640
> 66       666                    530
> 71       555                    450
> 77       470                    380
> 82       400                    325
> 88       337                    278
> 93       286                    240
> 100     217                    194
>
>
> --
> Neil Nicholson '81 VanaJetta 2.0 "Jaco"
>
> http://tubaneil.googlepages.com/
>
>
> http://groups.google.com/group/vanagons-with-vw-inline-4-cylinder-gas-engines