Overheating, need to change the thermostat?

Tiny
PICKYCANDI
  • MEMBER
  • 2005 BUICK RENDEZVOUS
  • 112,000 MILES
Overheating, changed the water pump, heater core, flushed the radiator, & changed the sensor. Then the heater stopped blowing hot when it started overheating. What else can it be? I don't wanna go head route necessarily. Pulling the dash out wasn't easy for the heater core.
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Thursday, January 12th, 2012 AT 2:32 AM

26 Replies

Tiny
FIXITMR
  • MECHANIC
  • 9,990 POSTS
Hello,

Here is a guide to help you change the thermostat out with instructions in the diagrams below to show you how on your car.

https://www.2carpros.com/articles/replace-thermostat

Check out the diagrams (Below). Please let us know what happens.
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Thursday, January 12th, 2012 AT 2:40 AM
Tiny
BRETT_GILBERT
  • MEMBER
  • 0 POST
Had this problem and had to replace the thermostat cost me $34.00
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Thursday, November 21st, 2019 AT 5:05 PM
Tiny
IAN MACLEAN
  • MEMBER
  • 3 POSTS
  • 2004 BUICK RENDEZVOUS
Six cylinder front wheel drive automatic 50,000 miles.

How do you change the thermostat what do you have to remove to get at it?
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Thursday, November 21st, 2019 AT 5:05 PM (Merged)
Tiny
BLUELIGHTNIN6
  • MECHANIC
  • 16,542 POSTS
Hello,
To better assist you, could you please list the engine size? 3.4L or 3.6L engine? Also, the eighth digit of VIN number will be helpful as well.

Thanks for using 2carpros. Com!
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Thursday, November 21st, 2019 AT 5:05 PM (Merged)
Tiny
IAN MACLEAN
  • MEMBER
  • 3 POSTS
The VIN number is, 3g5da03e24s58o878 and the engine is 3.4.
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Thursday, November 21st, 2019 AT 5:05 PM (Merged)
Tiny
BLUELIGHTNIN6
  • MECHANIC
  • 16,542 POSTS
Great, thanks for that information.

Below are the removal/installation instructions for your thermostat:

REMOVAL:
Remove the air cleaner and duct assembly.
Drain the coolant until the coolant level is below the thermostat.
Remove the crossover exhaust pipe.
Remove the radiator hose from the thermostat housing.
Remove the thermostat housing bolts and clean any sealer from the bolt threads.

(Removing the housing bolts)


https://www.2carpros.com/forum/automotive_pictures/261618_0900c1528009ed81_1.jpg



Remove the thermostat housing and gasket.
Remove the thermostat.
Clean the mating surfaces.

(The removal and installation of the thermostat)


https://www.2carpros.com/forum/automotive_pictures/261618_0900c1528009ed81_2.jpg



INSTALLATION:
Install the thermostat.
Install the thermostat housing and gasket.

NOTE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

Install the thermostat housing bolts and tighten them to 18 ft. lbs. (25 Nm).
Install the radiator hose to the thermostat housing.
Install the crossover exhaust pipe.
Install the air cleaner and duct assembly.
Fill the cooling system.

Hope this helps..
Thanks for using 2carpros.com!
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Thursday, November 21st, 2019 AT 5:05 PM (Merged)
Tiny
AMM
  • MEMBER
  • 7 POSTS
  • 2002 BUICK RENDEZVOUS
  • 6 CYL
  • AWD
  • AUTOMATIC
I am replacing the thermostat in a 2002 Buick rendezvous. I took the necessary hoses loose but no coolant came out? When I checked it before I started the repair there was coolant in the tank. Where did it go?
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Thursday, November 21st, 2019 AT 5:05 PM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,758 POSTS
Just because there is coolant in the reserve tank does not mean the radiator is automatically full. I don't know why you are changing the thermostat but you have other issues there that need to be found. You need to pressure test test the cooling system to find out wheere that coolant went and pray you didn't blow a head gasket already from overheating it.
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Thursday, November 21st, 2019 AT 5:05 PM (Merged)
Tiny
AMM
  • MEMBER
  • 7 POSTS
The vehicle did not have any heat in the heaters at all. Ice cold. That is why the thermostat was being changed.
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Thursday, November 21st, 2019 AT 5:05 PM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,758 POSTS
Not having enough coolant will give the same symptoms.
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Thursday, November 21st, 2019 AT 5:06 PM (Merged)
Tiny
AMM
  • MEMBER
  • 7 POSTS
The coolant was full. It was checked.
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Thursday, November 21st, 2019 AT 5:06 PM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,758 POSTS
You just said no coolant came out when you removed the hoses. That completely disproves that.
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Thursday, November 21st, 2019 AT 5:06 PM (Merged)
Tiny
AMM
  • MEMBER
  • 7 POSTS
Before the thermostat job was started the coolant was checked and it was full. Both in the jug and in the radiator. Don't quite know why it didn't show up anywhere. There was none in the crankcase either.
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Thursday, November 21st, 2019 AT 5:06 PM (Merged)
Tiny
PALEOMAN
  • MEMBER
  • 2 POSTS
  • 2002 BUICK RENDEZVOUS
  • 6 CYL
  • AWD
  • AUTOMATIC
  • 105,000 MILES
Need to replace the thermostat on my 2002 Buick Rendezvous. I would like to know what I need to remove and how to remove it so as to have access to the the two thermostat housing bolts?
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Thursday, November 21st, 2019 AT 5:06 PM (Merged)
Tiny
BLUELIGHTNIN6
  • MECHANIC
  • 16,542 POSTS
Remove the air cleaner and duct assembly.
Drain the coolant until the coolant level is below the thermostat.
Remove the crossover exhaust pipe.
Remove the radiator hose from the thermostat housing.
Remove the thermostat housing bolts and clean any sealer from the bolt threads.
Remove the thermostat housing and gasket.
Remove the thermostat.
Clean the mating surfaces.


https://www.2carpros.com/forum/automotive_pictures/261618_1_156.jpg




https://www.2carpros.com/forum/automotive_pictures/261618_2_104.jpg



Install the thermostat.
Install the thermostat housing and gasket.
Install the thermostat housing bolts and tighten them to 18 ft. lbs. (25 Nm).
Install the radiator hose to the thermostat housing.
Install the crossover exhaust pipe.
Install the air cleaner and duct assembly.
Fill the cooling system.
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Thursday, November 21st, 2019 AT 5:06 PM (Merged)
Tiny
AMM
  • MEMBER
  • 7 POSTS
We have replaced the thermostat, the vehicle engine does not overheat anymore so apparently the thermostat was bad. We have refilled it with coolant, bled the lines, tightened the radiator cap, checked for leaks but the heater does not heat. Any suggestions?
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Thursday, November 21st, 2019 AT 5:06 PM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,758 POSTS
With the engine at full operating temp, locate the 2 heater hoses where they go into the firewall and feel them to see if they are both hot to the touch.
If you find that they are both too hot to hold, then the heat in that vehicle is controlled by a blend door that regulates heated air flow. It is operated by an electric motor/actuator. The problem can be that the actuator is stripped or inoperative or the door itself could be damaged. This is what needs to be determined by examining the actuator and see if it is responding to heat change commands or not.
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Thursday, November 21st, 2019 AT 5:06 PM (Merged)
Tiny
AMM
  • MEMBER
  • 7 POSTS
Thank you Wrenchtech for your help. It turned out to be the radiator cap wasn't on tight enough to get the water circulating. Now the heater works.
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Thursday, November 21st, 2019 AT 5:06 PM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,758 POSTS
Radiator cap?
About the only thing that is going to cause is coolant loss. It has nothing to do with circulation but has everything to do with the system drawing the fluid from the reservoir when the engine cools down.
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Thursday, November 21st, 2019 AT 5:06 PM (Merged)
Tiny
AMM
  • MEMBER
  • 7 POSTS
Well, that's all it took after we got the thermostat in. That was faulty. If the cap is screwed down tight the coolant doesn't build up pressure to flow. It just escapes the system. This is my last transmission. Again thanks.
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Thursday, November 21st, 2019 AT 5:06 PM (Merged)

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