01 Siverado 5.3 Overheating

[hdheritage1]

blew upper rad hose put in new one added water still overheating,changed thermostat still overheat,replaced w/pump STILL OVERHEAT,tried to purge,STILL OVERHEAT,am i doing something wrong? not bleeding right? any help please

[GMTRUCKTECH]

CHECK THE FAN CLUTCH. GET A WATER HOSE AND FLUSH YOUR RADIATOR AND SEE WHAT COMES OUT. HOW MANY MILES?

[hdheritage1]

flushed rad clear 160,000 miles nuthin came out

[GMTRUCKTECH]

flushed rad clear 160,000 miles nuthin came out

 

HERE IS THE GM PROCEDURE GOOD LUCK

 

Engine Overheating

Step

 

Action

 

Yes

 

No

 

1

 

Inspect the coolant level.

 

Is the coolant level low?

 

Go to Step 11

 

Go to Step 2

 

2

 

Inspect the exhaust system for the following conditions:

 

 

• Damaged exhaust pipe

 

 

• Plugged catalytic converter

 

Did you find and correct the condition?

 

Go to Step 22

 

Go to Step 3

 

3

 

Inspect for a loose drive belt.

 

Is the drive belt loose?

 

Go to Step 4

 

Go to Step 5

 

4

 

Replace the drive belt. Refer to Drive Belt Replacement in Engine Mechanical -4.3L, Drive Belt Replacement - Accessory in Engine Mechanical - 4.8L, 5.3L and 6.0L, Drive Belt Replacement in Engine Mechanical - 6.6L or Drive Belt Replacement - Accessory in Engine Mechanical - 8.1L.

 

Was the repair complete?

 

Go to Step 22

 

--

 

5

 

1. <LI type=1>Inspect for obstructed radiator air flow.

    

2. If equipped with a 6.6L diesel, also inspect for an obstructed charged air cooler or debris between the radiator and air cooler.

    

Is the radiator air flow obstructed?

 

Go to Step 6

 

Go to Step 7

 

6

 

Clean the radiator. Refer to Radiator Cleaning .

 

Was the repair complete?

 

Go to Step 22

 

--

 

7

 

Inspect for an inoperative fan clutch. Refer to Fan Clutch Diagnosis .

 

Is the fan clutch operating correctly?

 

Go to Step 9

 

Go to Step 8

 

8

 

Replace the fan clutch. Refer to Fan Clutch Replacement .

 

Was the repair complete?

 

Go to Step 22

 

--

 

9

 

Inspect the thermostat. Refer to Thermostat Diagnosis .

 

Is the thermostat stuck in the closed position?

 

Go to Step 10

 

--

 

10

 

Replace the thermostat. Refer to Thermostat Replacement .

 

Was the repair complete?

 

Go to Step 22

 

--

 

11

 

1. <LI type=1>Fill the coolant to the specified level. <LI type=1>Perform a pressure test on the cooling system.

    

2. Inspect for external coolant leaks.

    

Are there any external leaks?

 

Go to Step 21

 

Go to Step 12

 

12

 

Perform a pressure test on the radiator cap.

 

Does the radiator cap hold pressure?

 

Go to Step 14

 

Go to Step 13

 

13

 

Replace the radiator cap.

 

Was the repair complete?

 

Go to Step 22

 

--

 

14

 

Inspect for combustion chamber gases leaking in the cooling system.

 

Are bubbles present in the coolant?

 

Go to Step 19

 

Go to Step 15

 

15

 

Inspect for a inoperative water pump.

 

Is the water pump inoperative?

 

Go to Step 16

 

Go to Step 17

 

16

 

Replace the water pump. Refer to Water Pump Replacement .

 

Was the repair complete?

 

Go to Step 22

 

--

 

17

 

Inspect for a blockage in the engine block coolant passages.

 

Are the engine block coolant passages blocked?

 

Go to Step 18

 

--

 

18

 

Perform the cooling system flush. Refer to Flushing .

 

Was the repair complete?

 

Go to Step 22

 

--

 

19

 

Check the engine oil.

 

Is the engine oil foamy and/or milky?

 

Go to Step 20

 

--

 

20

 

1. <LI type=1>Remove the cylinder head. Refer to

Cylinder Head Replacement - Left or Cylinder Head Replacement - Right in Engine Mechanical - 4.3L, Cylinder Head Replacement - Left or Cylinder Head Replacement - Right in Engine Mechanical - 4.8L, 5.3L and 6.0L, Cylinder Head Replacement - Left or Cylinder Head Replacement - Right in Engine Mechanical - 6.6L, or Cylinder Head Replacement - Left or Cylinder Head Replacement - Right in Engine Mechanical - 8.1L. <LI type=1>If equipped with a 8.1L engine, inspect the head gasket for correct installation. Refer to Cylinder Head Replacement - Left or Cylinder Head Replacement - Right in Engine Mechanical - 8.1 L.

Inspect the cylinder head and block for cracks.

 

Was a damaged/faulty component found?

 

Go to Step 21

 

--

 

21

 

Replace and/or repair the component as necessary.

 

Was the repair complete?

 

Go to Step 22

 

--

 

22

 

1. <LI type=1>Fill the cooling system to the proper level, if necessary.

    

2. Operate the engine.

    

Does the engine overheat?

 

--

 

System OK

[mooreapi]

HDHeritage,

How is it overheating. Does it do it regardless of whether you are moving, or only when you stand still, or does it just go from 0 to overheat in a minute or two?

 

I have a 2000 Silverado NBS with 5.3l. It now had 348K miles on it.

At around 150K or so, I let the truck sit for a week. When I got back and started it up, after a minute or two it overheated. Found out it was a stuck/froze thermostat. Replaced it and changed the Dexcool, all was well.

Now, since about 250K, if I sit and idle for long periods (especially with the AC on in hot weather) the temp gauge climbs and will eventually overheat (takes a while). If I touch the gas and raise the RPMs to around 1000, the temp will drop back to normal. Also, as soon as I start driving, it drops to normal and stays there.

I think I need to replace the water pump (impellers probably rotted away) and increase the idle speed (it seems to idle low, 5-600 RPM)

 

Matt