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The two connections on the sensor in the engine are known to get corroded.
Current:
2016 Cayman S
Former:
94 968 Cab 6 Spd. Black/Cashmere D1R SC
86.5 928 Garnet Red Metallic
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Yes, there are plenty of things you can check as a DIY, as mentioned above, but the problem is more likely the temp guage itself. I chased this same symptom for quite a while when I first bought my Cab. I also had an intermittant odometer problem and after the third or fourth instrument cluster extraction without a fix, I decided to bite the bullet and send it in for repair. They requested the whole cluster and not just the speedo, so while they had it, I asked them to check the temp guage. Sure enough, there is some sort of reisistor/coil/thermistor component that likes to go bad over time. They replaced it and it's been fine ever since.
- Darryl
1992 Slate Gray Coupe over Carrera Gray Full Leather interior....1 of 1
2006 Cayenne S Icelandic Silver Titanium Edition
2006 Cayman S Seal Gray over Black
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My 968 has the same symptom. Very sure it is the resistor/coil on the back of the gauge (like Darryl wrote above). The needle will jump around, going higher at unpredictable times. A light tap with a finger tip will usually (but not always) cause the needle to go back to normal display. Seeing it jump up to near the red zone after just a couple of minutes driving certainly is a good way to increase the heart rate. I have a vague memory that somewhere her on the forum is a more detailed description of the problem (vague memory that flash wrote something about it).
Roland
'93 Coupe Tip Silver on Grey, '02 911 C4S, '89 Vanagon Syncro -- (RIP: 944, 911SC, 931, MGB, VW Bug, GTO, Sprite.)
(This post was last modified: 03-26-2013, 01:25 PM by
968Syncro.)
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I had this same symptom, along with a burnt out bulb. I removed the gauge cluster, cleaned the grounds on the back of the instrument cluster and replaced the main bulbs with LEDs from Superbrightleds.com. All seems to be good now, with my voltage gauge and my temp gauge both working better.
This is the guide I followed:
http://forums.pelicanparts.com/porsche-9...ost7224814
-Matt
1993 Midnight Blue Porsche 968 Cabriolet (toy! Currently under restoration)
1995 Jeep Cherokee (war wagon, Zombie Apocalypse Response Vehicle)
2015 Mazda 3 (my reliable, nice car)
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Mine was pegged, usually. It would bounce down a bit every now and then. Pulled the cluster out just last week and dropped the whole cluster off at North Hollywood Speedometer & Clock Co. $95, back in day, and it works perfectly now.
Edit: I meant to put this under Voltage Regulator! Sorry, long day! A pegged temp gauge would have freaked me out!!!
1993 Wimbledon Green M030 Coupe! D1R Stage 3 Super Charger; Short Shift Kit; AC Tensioner; Splitter; Mesh Grille; Exhaust Shield; Caster, Tower, & Firewall Braces
1993 Wimbledon Green/Cashmere Coupe; D1R Short Shift Kit; leather dash; new paint; 52k miles
1987 Guards Red 928 S4; sport wheel; limited slip; heated seats
(This post was last modified: 04-30-2013, 12:52 AM by
ryker.)