Intermittent high engine temp,intermittent cab heat
 

11/22/2015
Problem(s) : Intermittent high engine temp,intermittent cab heat,
intermittent engine temp indication.

A short time ago I noticed no cab heat/defrost with the (dash)engine temp in the (normal?)
range.Thinking a bad thermostat I replaced it with a 195 degree one even though
I had replaced it about 6 months before.I have two engine temp gauges, the normal
dash one and a IEQUUS? aftermarket one. The dash gauge reads about in the middle (always has)
and the aftermarket about 165 degrees.I replaced the first thermostat (195deg) with a new
195 deg thinking it was bad remembering a normal 200 or so reading on the aftermarket
gauge.Shouldn't a 195 deg thermostat keep the engine temp near 200?? I've replaced the
aftermarket gauge sending unit also.

Sometimes everything works normal(dash gauge middle,aftermarket gauge 165?,and cab heat.)

On an abnormal day the whole engine warmup cycle -such as it is- seems to take longer than
normal. The dash gauge rises to the middle, the aftermarket gauge is off-scale low and NO
heat from the vents or defroster.A few mintues later -the colder day the longer- the dash
temp gauge rises to the top (aftermarket gauge still bottomed out). Suddenly the dash gauge
will start to slide back to the middle,the aftermarket gauge will rise to 165 and heat will
come from the vents or defroster whichever is selected.

Sounds like you have an air lock in the system from working on the t-stat and in need of a good burping.

If you can park it with the front up hill it will help to get the air out. With the motor cold remove the radiator cap and start it up. Let it run until it reaches operating temp, check the coolant level (top off as needed), replace the cap and you should be good to go.