

| Subject: | Coolant Temp Sensor Test. Generic vs VW. |
| From: | neil N |
| Date: | Mon, 5 Oct 2009 19:31:10 -0700 |
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/
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