Questions and Answers
Nissan Hard Body
Q. Dear Mr. Ciulla: I have what I hope is a simple problem with my 1989 Nissan Hard Body 4x4 King Cab with 120,00 miles. I first noticed that the heater blew cold air, but suddenly did when I repeatedly operated the temperature slide on the AC/heat control panel. Same thing the next day with no heat, but without being able to correct it with the temperature control slider.
Also, I then noticed that the engine was running hot. The temperature gauge was at the very high end of safe. I added some water to the radiator though it needed not much. I also noticed that the top radiator hose was cool when the engine temperature gauge read high normal and the radiator was hot. I am hoping that this is the thermostat. The radiator has not been flushed unless during warranty service several years ago (at 60,000 miles).
Also, there was last week a clacking sound upon starting the engine that sounded like a valve/lifter. It stopped after a few seconds when the oil began to circulate and quit altogether after two days. I hope that I have given you enough information to help you to help me.
Ken
A. A very common problem with that truck is the cable for the temperature selector gets kinked and twisted or the clip that holds the cable on to the control panel or heater box pops off. If you look under the dash on the passenger side you will be able to see the cable. Operate the lever back and forth and see if it moves full stroke smoothly in both directions. If it doesn't, and the clip is still attached, then the cable is kinked at the control lever. You'll have to pull the control; panel out and replace the cable. Don't even waste your time trying to straighten it out. Once it's bent it'll never work again.
When you replace the cable spray some CRC 5-56 on the rod the cable connects to at the heater box and make sure the door opens and closes smoothly without binding.
s for the cooling system, it looks like the thermostat is stuck closed. The top radiator hose being cold is a dead give away.
The clacking sound you heard when you first started the engine was probably due to the lifters. As soon as you built up oil pressure they pumped up and the noise went away. The fact that the noise is now gone may indicate that it was some dirt or sludge keeping the check valves in the lifters from sealing. You might want to try more frequent oil and filter changes for a while to try and clean some of that stuff out.
Additional Information provided courtesy of ALLDATA
