Today i was driving and for the first time ever, my temperature needle shot from below cold, to 3/4 of the way to hot within 3 seconds. My car never runs this hot, and so i turn on the heater to get some heat because it's cold outside, and all it's blowing is cold air. How can my engine say that it's running hot, and i still have no heat? It's never done this before, can someone help?

 

temp sensor maybe?

 

would that make my heater not work?

 

heater core

 

termastat went bad

 

i changed the thermostat

 

when you change it?

 

If your heater core is full of nothing then it won't matter how hot your engine is, you won't be getting any heat. It happened to me this winter in like -20C weather. (Check your coolant level, start the car without the cap on to let the air out. Warning, do not open the cap when the engine is hot).

If your waterpump is broken or the system is clogged then your coolant will sit still and won't go anywhere near the radiator to get cooled...

 

i just changed the thermostat, so that's not the problem

 

I didn't mention anything about the thermostat...

However, the fact that you changed it could cause the problem your having if you did not bleed the system properly afterwards. You need to run the car for a while with full heat on the climate control and the radiator cap on the first click (or no cap at all, its just messy though) to let the air out. Then unscrew the bleeder screw, fill the rad until straight coolant comes out the bleeder screw, tighten it back and put the radiator cap back on.

Like I said, if your heater core is full of air then its not going to let off much heat, nomatter how hot your engine is.

 

you prolly have a air pocket or coolant has leaked somewhere and the cause of that skyrocketing gauge was because of no coolant in the system.

thats my theory, hope that helps

 

Check the strength of the coolant.If its to week the coolant will turn slushy and the pump won't push it.Some times it will freeze in the heater core and not circulate.You can just drain a gallon out of the radiator and refill with straight antifreeze.
Glenn

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NJIN BUILDR &raquo;</TD></TR><TR><TD CLASS="quote">Check the strength of the coolant.If its to week the coolant will turn slushy and the pump won't push it.Some times it will freeze in the heater core and not circulate.You can just drain a gallon out of the radiator and refill with straight antifreeze.
Glenn</TD></TR></TABLE>

This is good advice, do as he says, i have experienced the same on a old car of mine, and it turned out that the coolant was good for -7 degrees C, and it had been -15 outside for a couple of days

 

Thanks a lot for the advice. I think the problem is the water pump. I'll change it and let you know if that was the problem