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So a couple weeks ago I noticed that my Mazda wasn’t blowing hot air from my heater if I wasn’t moving. As soon as I start driving it gets hot but at a stop light or something it blows cold air. I let that go on for about a week while I researched a lot and couldn’t find anything specific. I checked my coolant and realized I was a tad low. So I added some coolant and that was that. The problem didn’t fix. It still blows cold air when I stop and hot when I drive. And then today as I was driving to work on the freeway I noticed my temp gauge was way higher then normal so I sped up thinking the more air under my hood would cool my engine off and the temp went down. Then it would climb again and then drop. Then when I got to work I idled my car to see if my temperature gauge would go up. It didn’t. It stayed the same where it should be. Then on my lunch break I checked my coolant and I was waaaay below minimum so I added more coolant and on the drive home my temperature gauge was a tad lower then it should be but no overheated. When I idled my car when I got home it rose to normal levels. Anyone have this problem or know what may be the problem?

thanks for the help in advance !!
 

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possibly coroded vanes on water pump
time to have a mechanic check it over
if you lose cooling ability you can seize your engine
 

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Basically, it's the thing on the end of the water pump that spins and circulates coolant through the engine, radiator, and heater core (part that heats the air comming out of the vents). If coolant isn't circulating properly it can result in you not having heat from the vents and the engine possibly overheating.
 

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Sorry I’m not that advanced into cars
The water pump, that's driven by the serpentine belt, moves coolant (antifreeze-water mix) through the car with "fan blades" (impeller vanes). Despite the suggestion about "corroded vanes", more broadly and tangibly, I think you should be able to identify a clear source of leakage. It sounds like you've been losing a lot of coolant; the loss of coolant lets air into what should otherwise be a closed and pressurized system, full of coolant. When an air pocket is at your heater core (the little radiator that provides heat in the passenger cabin), you're getting cold air; when you accelerate and push coolant fast enough to displace the air pocket, you get warm air from the warm coolant. However, the insufficient coolant allows critical parts of your engine to get hotter than they should, risking catastrophic engine damage.

It's pretty simple to survey the engine bay for a major leak. See if you've got green coolant residue on the top of the splash guard under the engine. Look for wet coolant near the translucent reservoir on the passenger-side wheel well, or under the water pump (the pulley/structure below the belt tensioner). Look for wet coolant leaking from hose connections at the thermostat, heater core connections (to/from the firewall), or water inlet (on the top, battery-side of the engine).

You may not know all those parts readily, but Google Image searches will help you pick them out quickly. Once you identify the source of the leak, you'll have a place to start repairs. No Check Engine light, right? If yes, tell us what codes you get with an OBD-II reader (many auto parts stores will check for free). Until you identify the leak (and possibly until you fix it), I wouldn't recommend driving except for emergencies (and even in emergencies, try to secure more reliable transport). If your mild-moderate leak turns in to a major or catastrophic leak, your engine will overheat and cause enough damage to rival the value of the car.
 

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If you don’t have a leak then you have a blown head gasket. If you keep overheating the engine you will have a blown head gasket if you don’t already. Look at it this way, then you’ll get to learn about the 2.5 engine swap.
 

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So a couple weeks ago I noticed that my Mazda wasn’t blowing hot air from my heater if I wasn’t moving. As soon as I start driving it gets hot but at a stop light or something it blows cold air. I let that go on for about a week while I researched a lot and couldn’t find anything specific. I checked my coolant and realized I was a tad low. So I added some coolant and that was that. The problem didn’t fix. It still blows cold air when I stop and hot when I drive. And then today as I was driving to work on the freeway I noticed my temp gauge was way higher then normal so I sped up thinking the more air under my hood would cool my engine off and the temp went down. Then it would climb again and then drop. Then when I got to work I idled my car to see if my temperature gauge would go up. It didn’t. It stayed the same where it should be. Then on my lunch break I checked my coolant and I was waaaay below minimum so I added more coolant and on the drive home my temperature gauge was a tad lower then it should be but no overheated. When I idled my car when I got home it rose to normal levels. Anyone have this problem or know what may be the problem?

thanks for the help in advance !!
Hey 👋🏽, I’m currently parting my 2.3l out due to a rod knock in the motor and someone cutting me off to allow that to happen . If you need any parts let me know ! Message me on discord or reply to me on here for more information 👍
 
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