Hey all I got a new Dakota, 169,000 miles 1992 with the 2.5 and 5spd. My dad sold his 1st gen dakota while back running strong at 440,000 miles, so I'm looking forward to years of service. Anyways, after replacing all the necessary fluids and filters, new fuel line, and other small stuff, I replaced the rad with a junkyard find because it had a hole in it. This new rad does not leak and looked a little rusty on the inside, but not too bad. Anyways flush the entire system with water, add the jug of antifreeze with an approximate similar amount of water, fire it up. The fan (electric) turns on and operates well, after warming up the upper rad hose gets pretty hot like it should, and the lower one is almost at ambient temperature, nice and cool. This tells me that the water pump and thermostat are good, the rad is not clogged, and everything is circulating well.

However the temp gauge in the dash remains at the upper portion of the range, never hits H but it approaches and stays up there. My old Ranger barely left the C even in the hottest Florida traffic jam, however my Suzuki bike only turns its fan on when the needle actually hits H (they were made that way from factory, I checked). Anyways I'm basically just asking anyone else with a 2.5 if your normal operating temp is in the upper part of the range, and if not, then what could be my issue here? At first I was concerned about a clogged rad because it was a junkyard find after all, however the fact that the upper rad hose is so hot and the lower rad hose is so cool makes me think that everything is perfusing properly.

Any advice would be appreciated.

Thanks

 

could be a bad gauge or temp. sending unit. i took my gauge out and tested it with the battery and some alligator clips.

 

Mine never gets above half when its working properly.

 

Well I diagnosed the problem and this is how I did it. I replaced the thermostat with a 180 deg instead of the 195, and then let the truck idle to operating temperature. Once the coolant started flowing back into the top of the rad I took the temperature using my digital infrared thermometer at 174 deg. Then I ran back to look at the gauge on the dash, which was reading at about 75% towards the H.

Next step is to replace the temperature sensor, and if that does not solve the problem then I'm just going to live with it. Now that I know my truck is cooling properly it doesn't really matter to me that the needle stays near the H all the time.

Thanks for the good advice.