fastrat37

Purchased this Civic 6 months ago, 200K on it, now in the past few days I noticed that the temp guage was on cold and little or no heat inside, had just replaced the head gasket 2 months ago and all was fine. The t-stat that came with the car was still good when I checked it at head gasket time. So I thought I would just replace it with a good Stant super-stat. Installed it, topped off coolant, bled it and capped it, drove it several times put at leat 50 miles on it now and still little or no heat. I noticed the temp guage did start to rise some but then just goes back to cold again. The water valve in the heater hose is open and it was blowing hot just a month or so ago, now it's cold outside here in Colorado.
If the cooling system was air-locked, wouldn't the temp guage show hot? The sensor is still connected to the wire and not broken. STUMPED? I am, all I want is for this thing to blow out some freakin' hot air from the heater and it won't........what am I overlooking? Thanks in advance for offering up any suggestions to remedy this. Just after the head gasket replacement, I used my non-contact temp gun and was checking temps on the heater hoses, water neck and all was fine at around 175 degrees.......hmmmmm. Now what?

apexi_rsx

the the temp gauge dropping when ever u rev the motor? if so the thermostat is defective and leaking past the valve. i had this happen to me a long time ago. eve new t stats end up being defective.

fastrat37

No, the temp guage doesn't move with revving the motor. I did see it move up slightly into the normal area of the needle swing after I replaced the t-stat and was sitting idling for 10 minutes with it waiting to pick up the kids from the school bus. Then it went back to cold again and blew very little heat from the vents. I am going to be working on it again tonite looking for a plugged heater core next I guess. I still wonder if it's air locked though?

apexi_rsx

seems like when ur driving its pushing past the t-stat for it to be cooling off.maybe take it back and buy an OEM one not one from autozone or anywhere else.

fastrat37

THANKS for your input to this no heat problem..................The cooling system must have had an air-lock somewhere......the kids kept driving it and the temp guage pointer stays right in the middle of the range, no complaints of NO heat inside the car. T-stat seems to be working now too, the kids drive the crap out of it, uses a little oil.....I try to keep it full. I use Wal-Mart 10W-30 Super Tech High Mileage in the 5 quart jug for under $15 here in Colorado.
Let's call it fixed for now and wait for the next problem to crop up......stay tuned.

EJ8_Man

Using junk oil at the incorrect weight the next problem may be sooner then you hope. I used Walmart oil to break in my engine for 1500 miles, then drained it and revered it as poison.

Sounds like you did not properly burp the air from your system. You may still see benefit from following the proper steps to replacing the coolant.