Ok.. Got a 89 Dakota with a 3.9L. Its got a stock 195 degree thermostat that just ain't cutting it now that winter is coming on. The temp gauge gets to 25% at most and the cab heater barely takes the edge off.
So.. has there been any luck with putting in a 200 or 205 thermostat or maybe some cardboard in front of the radiator?
Just curious...
thanks.

 

The gauge is not linear...... plug in with a scanner that can read data, and see what temp the PCM thinks the engine is.

 

I agree find out if the engine temp agrees with the readout on the dash.
When I have had this problem I usually cover half the rad with cardboard and keep an eye on the temp. I haven't had an issue with my Dak. But you have to find out if your temp gauge is correct first. It may be that your heater core is not working properly.

 

As stated above, test the guage..... But I suspect a bad thermostat. If the guage is reading low and there is little heat, the t-stat is likely stuck open.
BTW if it was mine, and You do put a t-stat in it, I would go ahead and flush system, especially the heater core.

 

Agreed.....stuck thermostat.

 

DItto on that, the rust inhibitors in the coolant start to degrade after two years, it's best to flush and refill about that same time.

My preference is to disconnect and reverse flush the heater core since it can act like the filter and catch all sorts of crap that might be floating around.

Steve