The heater in my truck puts out zero heat. Temperature gauge never moves from "C" even after a 16 mile commute in city traffic.

Is this a thermostat problem?

second question, could truck running too cool be at least part of the reason I am failing emissions with high hydrocarbons?

 

IF your temperature guage is working, thermostat would most likely be your problem. That should also help your emissions. If it would come to replacing the heater core, they are easy to replace on the '88. Good luck.

 

Yes, it's possible for a stuck thermostat to cause both problems, and MORE. Heat in the engine is necessary for several reasons, including cooking the gas out of the oil so it keeps its viscosity.

What engine do you have?

 

It's a 351.

 

Id say it's time for you to do a antifreeze flush, new hoses, and a new thermostat.

Adrianspeeder

 

You should probably buy a new bypass hose with that t-stat. They're hard enough to put on new, but they're a nightmare trying to get them to reseal when they're old. It's a VERY short formed 90° hose that goes from the WP to the t-stat housing. #5 in the L pane.

 

I had the same problem a couple winters ago in my 88. Changed the thermostat, and the problem went away.

Mike B