So I own a 2004 Mazda 3 Sport.

Bought It used about 3 years ago. No real problems until recently. That problem is the heat.

I don't have any!!!

It shows my engine temp is Right on H the whole time I drive. The only time I can feel any heat coming out is when I accelerate to over 100, and put my hand on the vent.. Then I feel SOME heat.

Otherwise....nothing.


Please help, I have a 2 year old daughter and don't want to drive her around a freezing car.

 

Well...

Back in the old days (when we could all work on our cars with wrenches and tools, not computers), if I had a loss of heat or no heat, the first place I looked was at the thermostat.

They even come in various temperature setting and the function is to open or close depending on coolant temp. So yours may be stuck shut

And even new cars have to have thermostats...so that's where I'd look.

Good Luck

John

 

So the Thermostat is stuck???

That seems like something relatively easy to fix..

Is it?

 

It would definitely be the first thing I'd check. I actually just replaced mine (mine was stuck open so too cold) about an hour ago. It took me a couple of hours to complete but I also did an oil change and rotated my tires. Also wasn't in a hurry. From what I've read on several forums the aftermarket auto-parts store thermostats are crap so just spend a little more for the OEM one. I got mine from Jason at onlinemazdaparts.com for $52 shipped.

To replace:
-jack up front of car
-remove top engine cover (pops off)
-remove under engine cover (multiple bolts)
-drain coolant (unscrew drain plug and then gently pop out)
-as it drains slowly unscrew the resevoir cap to facilitate draining (open it all at once and coolant will shoot out about 2 feet, so slowly is important)
-use breaker bar w/ 14mm socket on tensionor pulley (top/forward pulley) and push towards back of car to take tension off the serpentine belt
-slide s-belt off of tensionor pulley (try to keep it in place of the rest of the pulleys, or note the path incase you need to reposition it)
-remove three...... 12mm? bolts holding tensionor assembly to engine, remove tensionor
-compress hose clamps (they should lock open if you squeeze them enough) and remove the hoses from the thermostat. More coolant will come out so be prepared. Lodge the hoses upright against something to stop the coolant from spilling more. There's a wiring plug right in front of the thermostat which you can unplug for a little more room.
-remove three 8mm bolts from thermostat housing, pull housing off of engine block (more coolant spillage happens now)
-make sure the mating surface on the engine is clean and wipe up excess coolant. If the gasket from the old thermostat stuck on the engine remove it
-stick new thermostat onto engine (gasket won't line up all nice and pretty at this point but will seat as you tighten the bolts) and tighten bolts. Hand tighten and then a little with a wrench, not too tight as you're screwing into aluminum.
-reattach hoses and seat the clamps, plug in plug if you disconnected it.
-replace tensionor assembly
-replace serpentine belt (remember to place the belt over the socket before drawing tension otherwise you can't get the belt onto the pulley)
-make sure radiator drain plug is replaced
-fill coolant reservoir with new 50/50 coolant to ~MIN line.
-turn engine on and allow to come up to operating temp at idle.
-add additional coolant as needed as the level will drop as the engine runs.
-replace reservoir cap and top engine cover

Voila!