Thermostat changed....fluctuating temp....air?

[Gossamer]

I changed out the thermostat in my 2002 Tahoe due to my 5.3 running hot.
Thermostat fell apart right when I removed the housing so I'm hoping that was the issue.
Ran great at just below 210 for over 25 miles, now temp goes up to about 235 then goes back down to about 210.
I am assuming air is in the system? What is the procedure on removing air bubbles?

Thanks

 

[bottomline2000]

I changed out the thermostat in my 2002 Tahoe due to my 5.3 running hot.
Thermostat fell apart right when I removed the housing so I'm hoping that was the issue.
Ran great at just below 210 for over 25 miles, now temp goes up to about 235 then goes back down to about 210.
I am assuming air is in the system? What is the procedure on removing air bubbles?

Thanks

1. How old is the water pump..replace after 100k miles.
2. Define fell apart..make sure no loose parts clogging the system.
3. Take the cap off the surge tank and let it idle to operating temp. Keep fluid at normal level. I would squeeze the upper radiator hose to force fluid thru the system until the thermostat opens. Put cap back on surge tank.
4. Check heater hoses to make sure warm fluid being circulated

If the temps drop when you rev the engine you probably gave a bad water pump.


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[HiHoeSilver]

Doesn't hurt to have the front end slightly elevated when burping it.

 

[Gossamer]

1. How old is the water pump..replace after 100k miles.
2. Define fell apart..make sure no loose parts clogging the system.
3. Take the cap off the surge tank and let it idle to operating temp. Keep fluid at normal level. I would squeeze the upper radiator hose to force fluid thru the system until the thermostat opens. Put cap back on surge tank.
4. Check heater hoses to make sure warm fluid being circulated

If the temps drop when you rev the engine you probably gave a bad water pump.


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Water pump is 1 year old

 

[Gossamer]

1. How old is the water pump..replace after 100k miles.
2. Define fell apart..make sure no loose parts clogging the system.
3. Take the cap off the surge tank and let it idle to operating temp. Keep fluid at normal level. I would squeeze the upper radiator hose to force fluid thru the system until the thermostat opens. Put cap back on surge tank.
4. Check heater hoses to make sure warm fluid being circulated

If the temps drop when you rev the engine you probably gave a bad water pump.


Sent from my SAMSUNG-SM-T377A using Tapatalk

It all fell apart but all parts are accounted for

 

[iamdub]

LS engines can be a pain to bleed. Here's a copy/paste from Alldata (I think):

1. Close the radiator drain ****;.
   
   
   
2. Fill the system through the surge tank opening.
   
   
   
3. Pre-mix a 50 to 60 percent solution of DEX-COOL and clean. drinkable water.
   
   
   
4. Slowly add the pre-mixed solution to the surge tank until the level is slightly above the surge tank split line.
   
   
   
5. Start the engine.
   
   
   
6. Idle the engine for 1 minute.
   
   
   
7. Loosely install the surge tank cap. Do not allow the system to build up pressure.
   
   
   
8. Cycle the engine from idle to 3000 RPM in 30 second intervals until the engine coolant reaches 99°C (210°F) and the thermostat opens.
   
   
   
9. Shut off the engine.
   
   
   
10. Refer to step 3 in order to remove the surge tank cap.
    
    
    
11. Start the engine.
    
    
    
12. Idle the engine for 1 minute. Fill the surge tank to 1/2 inch above the COLD FULL mark on the surge tank.
    
    
    
13. Install the radiator surge tank cap.
    
    
    
14. Cycle the RPM. Idle the engine to 3000 in 30 second intervals until the engine coolant reaches 99°C (210°F).
    
    
    
15. Shut off the engine.
    
    
    
16. Top off the coolant, as necessary, to 1/2 inch above FULL COLD mark on the surge tank.
    
    
    
17. Rinse away any excess coolant from the engine and the compartment.
    
    
    
18. Inspect the concentration of the coolant.

 

[RED TAHOE LS]

Make sure you TURN ON HEATER when purging system to get any air out of the system. I tend to do it the old way, 1" below radiator neck, let the engine idle till thermostat opens, have coolant ready to add to radiator when necessary, once you see the coolant flowing (it's burping out air @ this point) good in radiator, put cap on radiator, make sure overflow tank in on warm line , your through, Total time maybe 20 minutes. If upper/lower radiator hoses are not same temp, might consider new radiator , most common problem with hot engine. Good luck
David g...........