The International Cessna^® 170 Association

I have a c-145 engine. While flying my oil temp began to reduce to zero. Now there is no indication of oil temp. Is there a means of checking the system. If necessary, can a new temp probe/gage be had. Any comments will be appreciated.

The standard check for oil temperature gauges is to stick the probe from the engine in a pot of boiling water. If the gauge reads 212 then its fine otherwise you probably need a new gauge which will come as a complete unit with the probe and capillary tube attached. Its not that hard to change but its not on the list of things permitted for owners to do without an A&Ps oversight. The gauge is a Scott readily available from many sources such as Aircraft Spruce. Bill K

The oil temp gauge is constructed of a "bulb" of alcohol with a capillary tube which connects to a diaphragm/bourdon-tube gauge. As the oil heats the alcohol, it expands and applies pressure to the diaphragm which in-turn expands and moves the needle/movement within the gauge.
If the system develops a leak the alcohol leaks out and the gauge becomes inoperative with the meter-movement relaxing and leaving the needle on the lowest reading. This is what has happened to you. You need an entirely new Oil Temp gauge.

Get one from Aircraft Spruce:
http://www.aircraftspruce.com/catalog/i ... iltemp.php

OR:
http://www.aircraftspruce.com/catalog/i ... iltemp.php

Be certain to obtain the 5/8-18UNF x 5/8-18UNF adaptor which is sold with each, respective gauge, to fit your Continental.
(Avoids problems with potential leaks if you inadvertently have an existing adaptor which is not the latest type to match the gauge.)

Cessna Service Kit SK182-108B provides a kit for the installation of an electric oil temp gauge that fits in the same hole as the original. It comes with everything you need except circuit protection and firewall sealant. It appears to cover all of the 170 series and early 172's as well as most other models that used the capillary type gauge. Unfortunately, the current list price is $455.77 from Cessna.

gahorn wrote: Get one from Aircraft Spruce:
http://www.aircraftspruce.com/catalog/i ... iltemp.php

Be certain to obtain the 5/8-18UNF x 5/8-18UNF adaptor which is sold with each, respective gauge, to fit your Continental.
(Avoids problems with potential leaks if you inadvertently have an existing adaptor which is not the latest type to match the gauge.)

I purchased the one from aircraft spruce for my O-300 last Fall. P/N 10-11600 came as a complete set and did not require the additional adaptor. Fit perfectly and was a relatively easy installation.

Where can I find an original temp gauge or what it looks like?

That would be for a 1954 170B

https://www.aircraftspruce.com/catalog/ ... kkey=17659

It was a Rochester gauge just like these gauges sold by Aircraft Spruce except the originals had a green arc from 100°to 225° and a red line at 225°

If you have an old one that is nice but doesn't work, maybe the capillary is broken. You can have them overhauled several places including Keystone Instruments in Lock Haven PA. If you have no old gauge, you could buy one of these and send it to Keystone and have them redo the gauge face with the green arc and red line.

If your not putting together a show piece and just need a working temp gauge, buy the gauge from Spruce and put the green arch and red line on the outside glass yourself with either paint or carefully cut vinyl, then use a white dot of paint for a witness mark on the glass and gauge body so you can tell if the glass slipped.

To add to Bruce’s excellent suggestion: Be certain if you install a different gauge to Also Install a New, Matching Adaptor which goes With that gauge. Do not re-use an old adaptor with a new guage…as the “flare” inside the adaptors have changed over the years and a mis-match will result in a leak.