I had the same problem with my 244DL same year as yours. tried the
following to no avail: new hoses, water pump and thermostat. Then
installed a Nissens extra heavy duty tropical radiator from rprusa.
Installed it myself. Car has never even come close to overheating
again. Runs below center on the guage now. I also had the tc board
resoldered previous to replacing the radiator. If you have the
original plastic radiator, it probably needs to be replaced IMHO. HT

94 944T 93K
90 244DL 137K

Have the radiator checked for flow. Turning the heater on high will remove a bunch of heat from the cooling system that the radiator is suposed to. I have been told never to use a stop leak except in an emergency. It is designed to plug up holes which includes radiator core tubing. A good radiator shop can check it out and clean or rebuild it. Good Luck!

Well this may not be a lot of help but I just went through the same thing with an 86 300zx. Cost an arm and leg doing the hoses, thermostat, flush, stop leak, can't remember what else. kept taking the car in and geting it back "fixed" only for it to heat right back up, twice on the way home from the mechanic.

Turned out to be the Radiator was clogged up. put in a new one... problem solve. I'd try the less expensive fixes first

Hey,

Replace the expansion tank cap with a used one, and while you are at it, make sure that the expansion tank itself is not cracked. My overall feeling on this is your water pump is caput, so if that hasn't been done in a while it might be your culprit (plus you can do the t-belt at the same time)

Happy Bricking!!!

Richard
87 245 DL 339,000 km
82 242 GLT 121,000 km

Is it truly overheating or are you reacting to the gauge going into the red?

I had this on my '86, and brother had it in his '89.

If it's merely the gauge (versus boiling over), then it's likely to be the compensating board. The comp board is installed into the cluster PC board, but you must dismount the PC board from the cluster housing -- 7 screws. The first picture below shows where the compensating board fits.

The second and third images give you a close-up of the area.

Often (but not always) resoldering the comp board and cleaning and tightening the 4 connecting pins solves the problem. To tighten the pins you can gently, carefully squeeze the female connectors (on the comp board) so they grip the pins (on the cluster PC board) more tightly.

If this doesn't help, you can certainly find a replacement board, perhaps new from the dealer $$. For my car, I replaced the IC and transistor on the board. That solved it.

Another approach that others have used successfully is to eliminate the comp board by bypassing it. You merely connect two of the four pins -- I don't know which two, but it's in the archives.

Have you tried to see if the problem is the temperature compensating board? Next time the temperature goes up toward the red, give the dash a whack. If the temperature needle starts down, the comp board is the likely culprit. This is a common problem, I have it in my '86 and '88. There are fixes in the archives.