Heater was blowing cold air so on the advice of this forum I replaced the thermostat. Temp gauge never went over 1/4. Now it goes just slightly past 1/4 and I get heat IF I am driving. The car will not "warm up" if I leave it in the driveway running.

Feels like I almost there but not quite. The best I have come up with is that I get heat when the water pump is running faster (higher engine RPM). Could this mean a clog somewhere where I am trickling water by and only high RPM gets enough water through the heater core to heat the air. What about air pockets?

I have seen in other forums that the gauge should normally run at 1/2. Is that correct?

Am I a power flush away or should I try something else? (It is too cold here to use my hose to flush)

Also do I neeed to BLEED the cooling loop for air?

 

leaning towards clog since if water pump was dead car would likely overheat.....are the heater hoses warm going to and from the heater core?

 

I had the same thing happen on my 99 sc1, no heat in the car, the return line from the core was ice cold so i had the cooling system flushed twice and now it heats like a charm, its a good first step. Im guessing the previous owners dumped some stop leak in the system for a quick fix, now just waiting to see if im loosing coolant somewhere....

 

i fear forgotten_One has forgotten one -- to come back.....

 

Have not had a chance to try the flush yet (Freezing New England temperatures and a foot of snow got in my way, so I fear I will need to pay someone to do it) One more question: I replaced the thermostat and the gauge went from just under 1/4 to just over (about a needle width). some have said I should be at 3/8 up to 1/2 on the coolant temp gauge. Wondering if something else I should check or if that is normal.

 

ECTS may need replacing (Engine coolant temp sensor) -- be sure to replace connector as well as ECTS (Connector is dealer only item)

 

Make sure you have enough antifreeze in the system. You can't rely on the color, you must test it. Those long skinny heater lines are the first to freeze and the last to thaw (from the engine heat).