Oil Temperature Gauge "Flicks"
Thread Starter
7th Gear
Joined: Aug 2021
Posts: 7
Likes: 1
Oil Temperature Gauge "Flicks"
My 1994 C2 Cabriolet has an odd problem. The Oil Temperature Gauge "fliks" at higher temperatures. If driving in slower traffic (city stop and go at lights/stop-sign) it will rise up to about the 9 o'clock position in a pretty normal fashion then it will rapidly climb to the 10, then drop to the 8 then bounce between the 9 and 10, then flick up to the 12 (giving me a heart attack). Tapping the gauge will cause it to level down just below the 9 o'clock position. After a bit more driving it will flick back up to the top.
I've checked the oil fan via shorting the relay as per http://p-car.com/diy/fan/ and both slow and fast work as expected. I also checked the G12-G18 resistance and it is within a reasonable range. Passenger front fender feels warm under these conditions so I am guessing the oil is flowing to the front passenger radiator just fine. As far as I can tell the fan never comes on though.
Given the fan works, the termristor seems reasonable, the only other options I can think of are the CCU is FUBAR (looks like some prior owner put the 993 model into the 964), or the temperature gauge itself is shorting somewhere.
I cannot, however, find good ways to diagnose if the gauge itself is having trouble. Page 97 of the wiring diagram makes it look like the oil temperature gauge is just a measure of the oil temperature sensor, direct wire passthrough from to the oil temperature sensor. Since tapping the gauge will cause it to flick around, I'm inclined to think this meter is just busted.
Has anyone tried debugging the gauge itself and have any ideas on ways to clean/replace parts? Replacement for the instrument cluster is $$$ and if a simple part can be replaced instead that would be preferable.
I've checked the oil fan via shorting the relay as per http://p-car.com/diy/fan/ and both slow and fast work as expected. I also checked the G12-G18 resistance and it is within a reasonable range. Passenger front fender feels warm under these conditions so I am guessing the oil is flowing to the front passenger radiator just fine. As far as I can tell the fan never comes on though.
Given the fan works, the termristor seems reasonable, the only other options I can think of are the CCU is FUBAR (looks like some prior owner put the 993 model into the 964), or the temperature gauge itself is shorting somewhere.
I cannot, however, find good ways to diagnose if the gauge itself is having trouble. Page 97 of the wiring diagram makes it look like the oil temperature gauge is just a measure of the oil temperature sensor, direct wire passthrough from to the oil temperature sensor. Since tapping the gauge will cause it to flick around, I'm inclined to think this meter is just busted.
Has anyone tried debugging the gauge itself and have any ideas on ways to clean/replace parts? Replacement for the instrument cluster is $$$ and if a simple part can be replaced instead that would be preferable.
Racer
Joined: Oct 2017
Posts: 272
Likes: 17
From: Cos Cob, CT
My oil temp and pressure gauge were acting up and I had to tap on it to get it to settle to its proper reading as well.
Took out the gauge, disconnected the wires and cleaned all of the connections. After doing that it seems to have fixed the issue.
Took out the gauge, disconnected the wires and cleaned all of the connections. After doing that it seems to have fixed the issue.
