No heat

Tiny
B3000ROSS
  • MEMBER
  • 2007 MAZDA B3000
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 80,000 MILES
I can only get cold air out of my vents, even when I have the dial cranked to full heat! It's not a problem right now but Winters coming. Any suggestions as to where I should check first?
Monday, August 16th, 2010 AT 7:39 PM

13 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Be sure both heater hoses are getting hot, If only one is hot you may have a plugged heater core or heater control valve that isn't working.

Read the guide below, it will help.

https://www.2carpros.com/articles/car-heater-not-working

The heater control valve is pictured below
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Monday, August 16th, 2010 AT 7:44 PM
Tiny
PMLWALKER
  • MEMBER
  • 2 POSTS
  • 2000 MAZDA B3000
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 108,200 MILES
I have a 2000 Mazda B3000 pickup. I have had the water pump and thermostat replaced. I have no heat. The water in my radiator looks like muddy water! What can be done to resolve my heat problem and I guess clean my radiator?
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Tuesday, December 18th, 2018 AT 5:35 PM (Merged)
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Get the radiator and heater core flushed and retest.
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Tuesday, December 18th, 2018 AT 5:35 PM (Merged)
Tiny
PMLWALKER
  • MEMBER
  • 2 POSTS
Thank you for replying!

Would you recommend that being done at a radiator shop or could I buy a flush kit from Advance Auto or some other part supply company?
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Tuesday, December 18th, 2018 AT 5:35 PM (Merged)
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
If the radiator is clogged badly, you need a radiator shop to perform the job as the radiator has to be serviced.

No flush kit would be able to clean the engine with a one time flush.

Heat from engine operation works well to flush out the system. Try doing it without any flush kit first. Use water to flush out as much as possible and disconnect the heater core to back flush.

Reconnect and top up with water. Run engine without radiator cap and heater at maximum heat for a about 5 minutes, keep topping up the water till it stabilises. This is to bleed the system of air.

If water tends to gush out, stop engine and wait a few seconds to allow air to escape. Once level stabilises, close radiator cap and run to operating temperature for a few minutes. Allow to cool before removing the radiator cap.

You need to repeat this flushing and bleeding process a few time to get the stuck grime inside engine to be cleared. Once water seems to be rather clear, You can either use the radiatro flush kit or if you feel that the system is sufficiently clean without necessity of further flushing, drain and replace with coolant.

Ensure bleeding is done correctly and replace hoses that are not in good condition.
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Tuesday, December 18th, 2018 AT 5:35 PM (Merged)
Tiny
KENCOBURN
  • MEMBER
  • 1 POST
  • 2000 MAZDA B3000
  • 3.0L
  • 6 CYL
  • 2WD
  • MANUAL
  • 139,000 MILES
I recently changed my thermostat and flushed my block due to overheating. Now I have no heat blowing through my vents, it blows air but no heat. Is there a fuse that may operate the heater?
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Tuesday, December 18th, 2018 AT 5:35 PM (Merged)
Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
I would say that you have an air lock in the heater system, try bleeding the cooling system with the front of the car elevated slightly, when the heater is purged of air, with the heater on, both hoses going to the heater will be hot to touch.
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Tuesday, December 18th, 2018 AT 5:35 PM (Merged)
Tiny
ROGER4364
  • MEMBER
  • 1 POST
  • 1994 MAZDA B3000
  • 6 CYL
  • 2WD
  • MANUAL
  • 164,000 MILES
I am getting no heat from my heater. The radiator fluid is full. My temperature guage just stopped working. Is there any connection with no heat and temp guage not working?
Thanks
Roger
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Tuesday, December 18th, 2018 AT 5:35 PM (Merged)
Tiny
LEGITIMATE007
  • MECHANIC
  • 5,121 POSTS
Well the temp gauge is on the other side of the the thermostat, which means if the thermostat is stuck closed then fluid is not getting to the heater core, nor is it reaching the engine coolant temp. Sensor, so try changing out the thermostat. And let me know how it goes
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Tuesday, December 18th, 2018 AT 5:35 PM (Merged)
Tiny
PJA69
  • MEMBER
  • 1 POST
  • 1999 MAZDA B3000
  • 6 CYL
  • 2WD
  • AUTOMATIC
I have a mazda b3000 1999, it gets warm but not hot and most of the water ends up in the reservoir. Has new radiator and thermostat. Why is there no real heat coming inside?
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Tuesday, December 18th, 2018 AT 5:35 PM (Merged)
Tiny
ERNEST CLARK
  • MECHANIC
  • 1,730 POSTS
I'm not understanding what you mean by "water ends up in the reservoir"? There should always be coolant in the reservoir.

As for the heat, I'm assuming your blower and dash controls work fine. If the heat isn't getting hot enough, could be a partially blocked heater core, a leaking vacuum line/solenoid in the HVAC unit and/or a stuck blend door.
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Tuesday, December 18th, 2018 AT 5:35 PM (Merged)
Tiny
2CP-ARCHIVES
  • MEMBER
  • 4,540 POSTS
  • 1998 MAZDA B3000
  • 147,890 MILES
I have a 1998 mazda b3000 and the heater only blowing cold air, what should I look for
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Tuesday, December 18th, 2018 AT 5:35 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Check the following: thermostat, heater core, heat control valve if it has one and also if the air blend door is opening to the heat position-start ere
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Tuesday, December 18th, 2018 AT 5:35 PM (Merged)

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