On Sat, 5 Jun 2004 18:11:32 -0700, "Mike Noel"
wrote:

Now that summer has come to Arizona, my oil temp is running about 2/3 of the
way between 180 and red line. My mechanic checked the oil cooler bypass
valve and said it was OK, so I had decided to send in the oil cooler for
cleaning and service. Checking the engine log for the last time work was
done on the cooler, I found an entry about 5 years ago saying the cooler had
been cleaned, then the next entry said the oil temp gauge was reading about
20 degrees too high, but there is no entry for corrective action to the oil
temp guage, wiring, or sender.

Looks like I need to check the gauge system myself for accuracy and probably
replace something. Do you just drop the sender into hot water and compare
the panel guage reading with a couple of cooking thermometers? If there is
a discepancy, is it the sender that should be replaced first, then replace
the guage if necessary?

Unless things have changed substantially, the sender/gage setup on the
older Pipers is a real pain. The sender & gage p/n/vendor/working
resistance has changed over the years, and Piper didn't useta be much
help in sorting it out.

The first step would indeed be to get a replacement crush gasket and
yank the sender and boil it. If the boiling water trick (don't forget
to ground the sender) reveals an indicating problem, the easiest thing
to do is contact Air Parts of Lock Haven.

http://www.airpartsoflockhaven.com/

Again, it's been a few years, but they were quite helpful in sorting
out the mess. It is possible that the wrong sender has been installed
at some point, or that the "right" sender for your gage is no longer
available. In either case, they can calibrate your gage and "match" it
to either a new sender, or your sender if it is functional.

TC