92 968 Running hot (temp mid way and stable) but fan...
09-04-2012, 07:53 AM
#16
Instructor
There is a good writeup for coolant system troubleshooting at Clark's Garage. http://www.clarks-garage.com/shop-manual/cool-03.htm
Also relevant is fan operation troubleshooting:
http://www.clarks-garage.com/shop-manual/cool-01.htm
Also relevant is fan operation troubleshooting:
http://www.clarks-garage.com/shop-manual/cool-01.htm
Last edited by mbardeen; 09-04-2012 at 12:46 PM.
09-07-2012, 11:12 PM
#19
Shameful Thread Killer
Rennlist Member
Rennlist Member
Found this write up while searching for something else. Seemed plausable. I'm going to clean these grounds on the inst cluster this week when I do my odo gear.
My 968's temp gauge would frequently sit at the 10 o'clock mark and beyond when driving in the city or waiting at stop lights. It climbed normally from 7 o'clock to 8 or 9 o'clock positions until warmed up in the morning, but after that it often appeared to be overheating. I also saw that the gauge fluctuated between 10 o'clock, pegged at the top, and 9 o'clock when driving but usually tapping the plastic gauge cluster shroud w/ my finger would stop these rapid changes. The gauge was obviously being wacko but I wasn't sure if my car also had some kind of cooling problem since it spent so much time at the 10 o'clock position.
So the other day when changing the battery I decided to pull out the gauge cluster again. Looking carefully at the back there are two oval-shaped caps fastened w/ 10mm nuts [1 each]. Removing the nuts & washers allows both oval caps to be removed and they contain brass grounding posts as pictured:
No Pics....
I proceeded to clean all of the brass surfaces of grime and corrosion then put everything back together. If you do this then be very careful not to shock, bend, or overtighten anything on the back of the cluster. When I put it all back together I connected the new battery and road tested it for a couple of days. Now my temp gauge rides slightly below the 8 o'clock mark whenever the car is moving. When it's stopped, the gauge goes to SLIGHTLY ABOVE 9 o'clock [but nowhere near 10 o'clock] before the fan relay clicks and temp reading returns to 8 o'clock. This appears to be perfect operation so I'm stoked w/ the result.
I've seen lots of 944/968 owners post about the engine running hot and folks suggesting radiator temp switch or fan relay replacement, new thermostat, fan resistors, etc. Before you spend a lot of money diagnosing the problem, I'd suggest making sure that your temp gauge is grounding properly and cleaning it like I did - it's free. You can also bleed the cooling system which is what I tried first but that didn't help.
In the next few days I'll post whether this fixes the fuel gauge problem as well. I've read about folks filling their gas tanks but the fuel gauge reads between 3/4 and 4/4 full, and that's what mine does.
My 968's temp gauge would frequently sit at the 10 o'clock mark and beyond when driving in the city or waiting at stop lights. It climbed normally from 7 o'clock to 8 or 9 o'clock positions until warmed up in the morning, but after that it often appeared to be overheating. I also saw that the gauge fluctuated between 10 o'clock, pegged at the top, and 9 o'clock when driving but usually tapping the plastic gauge cluster shroud w/ my finger would stop these rapid changes. The gauge was obviously being wacko but I wasn't sure if my car also had some kind of cooling problem since it spent so much time at the 10 o'clock position.
So the other day when changing the battery I decided to pull out the gauge cluster again. Looking carefully at the back there are two oval-shaped caps fastened w/ 10mm nuts [1 each]. Removing the nuts & washers allows both oval caps to be removed and they contain brass grounding posts as pictured:
No Pics....
I proceeded to clean all of the brass surfaces of grime and corrosion then put everything back together. If you do this then be very careful not to shock, bend, or overtighten anything on the back of the cluster. When I put it all back together I connected the new battery and road tested it for a couple of days. Now my temp gauge rides slightly below the 8 o'clock mark whenever the car is moving. When it's stopped, the gauge goes to SLIGHTLY ABOVE 9 o'clock [but nowhere near 10 o'clock] before the fan relay clicks and temp reading returns to 8 o'clock. This appears to be perfect operation so I'm stoked w/ the result.
I've seen lots of 944/968 owners post about the engine running hot and folks suggesting radiator temp switch or fan relay replacement, new thermostat, fan resistors, etc. Before you spend a lot of money diagnosing the problem, I'd suggest making sure that your temp gauge is grounding properly and cleaning it like I did - it's free. You can also bleed the cooling system which is what I tried first but that didn't help.
In the next few days I'll post whether this fixes the fuel gauge problem as well. I've read about folks filling their gas tanks but the fuel gauge reads between 3/4 and 4/4 full, and that's what mine does.
