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This could be a few different things. First, are the cooling fans turning on when they should? Next, did you flush the radiator to see if that helped? Have you checked for an issue with a head gasket? Are you sure there is no air in the cooling system? If you didn't properly bleed the system while reinstalling the coolant, an air pocket can cause this.
Take a look through these links. I included flushing the radiator, radiator fan info and how to check for a bad head gasket. I have to be honest, based on your description, it sounds like either you have air in the system or the new thermostat is sticking. Regardless, here are the links. I will also include directions for draining and refilling the cooling system which discusses how to bleed the system.
https://www.2carpros.com/articles/coolant-flush-and-refill-all-cars
https://www.2carpros.com/articles/how-an-electric-cooling-fan-works
https://www.2carpros.com/articles/head-gasket-blown-test
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Here are the directions for draining and refilling the coolant. They include bleeding the system. The attached pictures correlate with these directions. By the way, I realize you know how to drain it because you already did it to replace the pump. I'm adding this because it discusses the refilling process too.
Draining and Filling Cooling System (LX9)
Tools Required
- J 26568 Coolant and Battery Fluid Tester
Draining Procedure
pic 1
Caution: With a pressurized cooling system, the coolant temperature in the radiator can be considerably higher than the boiling point of the solution at atmospheric pressure. Removal of the surge tank cap, while the cooling system is hot and under high pressure, causes the solution to boil instantaneously with explosive force. This will cause the solution to spew out over the engine, the fenders, and the person removing the cap. Serious bodily injury may result.
1. Unscrew the surge tank cap to remove vacuum when draining coolant.
2. Raise the vehicle. Refer to Vehicle Lifting.
3. Place a container under the radiator drain.
pic 2
4. Unscrew the radiator drain plug until coolant flows out the radiator drain.
pic 3
5. Place a large pan under the engine block left coolant drain plug and remove the drain plug.
6. Follow the appropriate procedure based on the condition of the coolant.
Normal in appearance-Follow the filling procedure.
Discolored-Follow the flush procedure.
Fill Procedure
pic 4
Notice: The procedure below must be followed Improper coolant level could result in a low or high coolant level condition, causing engine damage.
1. Install the engine block left coolant drain plug.
2. Close the radiator drain plug.
3. Lower the vehicle.
4. Vehicle should be level.
5. Add a mixture of 50/50 DEX-COOL- antifreeze and clean drinkable water until the level stabilizes at the weld seam on the surge tank. Refer to Capacities - Approximate Fluid in Maintenance and Lubrication.
pic 5
Bleeding the system
6. Unscrew the coolant bleed screw on the engine until coolant comes out of the bleed screw.
7. Close the bleed screw.
8. Add coolant until the level stabilizes at the weld seam on the surge tank.
pic 6
9. Install the surge tank cap.
Important: DO NOT exceed 2,200 RPM.
10. Start the engine and run at 2,000 RPM until the engine cooling fans turn ON.
11. Remove the surge tank cap.
12. Refill to the weld seam on the surge tank.
Important: Coolant should be at the full cold mark when the system cools.
13. Install the surge tank cap.
14. Inspect the concentration of the engine coolant using J26568.
15. Rinse away any excess coolant from the engine and the engine compartment.
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Let me know if any of this helps or if you have other questions. I have a feeling it is something simple.
Take care,
Joe
Images (Click to make bigger)
Wednesday, October 28th, 2020 AT 2:26 PM
(Merged)
