My '89 Si's temperature gauge has been on the rise, and I have to leave the heat on to keep it down. I have a new thermostat, but been too lazy to put it in. The weird part is that the temp gauge will go all the way up, yet the fan will blow cold air even when it's set to full hot. How is this possible? Is my gauge just faulty?

 

water pump try that

 

Can a water pump be intermittent?

 

does the radiator get hot? could be ur temp senser to

 

It's weird, one second the air will be cold, with the gauge on red, then after a second the air will be hot as a JV Cheerleader on prom night. Also, once it starts blowing hot, it will blow cold intermittently this makes no sense. the thermostat only stops flow through the radiator, right? Coolant is always flowing through the heater core correct? I'm thinking water pump now....

 

yeh open ur radiator to see if the coolant is flowing thru it when the thermostat opens thats how i learned to see if the water pump works

 

You said your thermostat needs replacement. Do it. It might be that.

If the problem persist it probably is a faulty gauge. It has happened before to people I know.

 

Make sure there's WATER in the system. Top it off... SOunds like the classic "crack in the plastic POS radiator" syndrome to me.

 

No.

 

to check if water pump el workin, squeeze the upper coolant hose to see if there is pressure.