Haven't started looking into the problem, just looking for ideas. I have an '86 Vette that was just purchased that seems to have two problems:

1. The coolant temperature display on the dash always stays on LOW regardless of how long the car is driven.
2. I am not getting heat inside the cabin, regardless of whether the manual or auto control is used. I have run the temperature setting to it maximum temperature with no results. The fan is working and blows cold air at all times.

Does anyone have any ideas as to where I should start looking at these problems.

TIA
Bob

 

Missing or stuck (open) thermostat?
Have you checked the coolant level?

 

You may need a new temp sender (pass head between #6 and #8)
http://members.shaw.ca/agent86/Fuel,...%20Dispaly.pdf
Electronic climate control diagnosis
http://members.shaw.ca/dankai/AC%20Electronic.pdf
Manual climate control diagnosis http://members.shaw.ca/dankai/Air%20...0%20Manual.pdf

 

Check and make sure the heater core is even connected, I have an 86 and the heater is by passed,of course I'm in Fla so it don't matter much I'll replace it some day when I'm bored (real bored) but up north it's kind of important Brrrr heater cores are not a C-4 strong point they leak or it could be blocked, after the engine is hot put your hand on the top hose running into the heater core and then the bottom hose coming out if the top hose is hot and bottom is cold then the core is blocked inside. I Also agree start from scratch check coolant level and t-stat, hoses, etc. The temp gauge could be related or a seperate issue but I'd do all the basic stuff first. Good luck

 

Thanx for all the advice. Guess I've got something to keep me busy today. I'm hoping its something as simple as a missing thermostat. The car had a crate engine installed before I bought it, so they may not have included the thermostat.

 

When I got my 86 the heater would not work because the valve was stuck shut. The control arm moved ok but if you looked carefully you coud see the spindle did not move. Its quite easy to replace the valve if you need to

Barry

 

Well, i found solutions to a couple of my problems today.

1. the only part of the thermistat in the housing. I replaced it with a
new 180 degree thermistat.
2. the coolant temperature sensor wasn't even connected. I now get
a "Coolant Temperature" reading on the dash.
3. I now get heat in the car; unfortunately, the vacuum operated valve
on the side of the heater box must be operated manually to open it.
This is something more i have to look into.

I have a couple of other questions though:

1. what temperature should the '86 Vette run at. unless the coolant
temperature readout isn't calibrated, i'm running between 200 & 210
degrees under normal driving conditions. Is that to hot? I thought
it seemed high. The coolant fan is operational, by the way.
2. does anyone know what the sensor is that mounted between #1 &
#3 plug on the head? thats another sensor that isn't wired to
anything. what color wire should be connected to it?
3. there is some sort of sensor (i think) that is mounted on a bracket
connected to rear bolt of the thermistat housing. Its got two wires
(BR w/BLK stripe, and what looks like a grey wire) connected to it
along with what seems to be a vacuum line. This sensor is mounted
under the plenum, behind the fuel rail and the #1 injector. Does
anyone know what it might be?[/B]
Sorry for the long post, but any help will be greatly appreciated.

TIA

 

Your running temps are normal. The switch in drivers head is the aux fan switch. Should be a dark green wire running to it (if you have the optional aux fan)
The part that is mounted to thermo housing is part of the EGR.

 

thanx for the input.

the reason why i asked about the EGR solonoid is because the connector isn't securely locked to the solonoid and the connections seem to want to vibrate loose as the engine is running.

looks like just something else that needs fixed!!!!

thanx again