My 94 gsr is overheating I've replaced the thermostat last night and its still overheating, the hose leading to the thermostat is cold does that mean the thermostat is not opening?

I have to run the car with the heat on for now and it works fine would the fans kick in when you turn the heat on?

 

did you try water pump?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AllmotorJunkie &raquo;</TD></TR><TR><TD CLASS="quote">did you try water pump?</TD></TR></TABLE>

no not yet actually Im hoping its not that bad

 

You said lower radiator hose is cold. How about the upper radiator hose? Hot/cold along its length?

If the radiator is plugged, then even when the thermostat opens, the flow thru the radiator is very small. Lower (return) hose is cold, but the flow is so small there's not enough cooling. If this is true, it would overheat while driving - maybe even worse than idling.

The radiator fans aren't automatically triggered by the heater. Do they run? When?

I'm not sure, but I think if the water pump was bad, then the heater wouldn't help to cool the engine.

 

yeah the lower rad hose is cold but the top one is hot throughout

the fans come on when I turn the heat on so I know the fan is working also I checked for bubles in the coolant and there was alot could this be the problem?

 

I vote for a plugged radiator. See what you can from the radiator cap. Any crud in there?

Maybe when you open the heater valve that makes enough flow so that your fan switch finally sees some hot water & runs the fans. There's nothing in the electrical system to trigger that to happen.

Not to insult you, but are you sure your thermostat is OK? Installed backwards? Blocked by a messed-up gasket?

If you bleed air out properly in the first place you shouldn't keep getting bubbles. That could be a sign of a bad headgasket. But I think with a bad headgasket, the heater wouldn't help things.