Drain Engine Coolant in 2005 Chevy Silverado 2500 HD

there is a drain at the bottom of the rad some are at the very bottom facing the ground some are facing the engine at the bottom of the rad. if you can`t find it just disconnect the lower rad hose.

the dealer sells the FSM book
and alldata.com has it online.

this might be important for you to know
Quote:

08-08-49-002: False Triggering of Low Coolant Level Warning Message (Reprogram HVAC Control Module) - (Feb 13, 2008)

Subject:
False Triggering Of Low Coolant Level Warning Message (Reprogram HVAC Control Module)

Models:
2007-2008 Chevrolet Silverado 2500 and 3500 Heavy Duty Series Only
2007-2008 GMC Sierra 2500 and 3500 Heavy Duty Series Only
with 6.6L Diesel Engine (VIN 6 -- RPO LMM)

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Condition
Some customers may comment that a "COOLANT LEVEL LOW ADD COOLANT" message is displayed in the Driver Information Center (DIC) even though the coolant level is normal.

Cause
This condition may be caused by a false reading during off-road driving or in high slush conditions.

Correction
Do This - Reprogram the HVAC control module.
Don't Do This - Do not replace the coolant level sensor, HVAC control module or radiator surge tank.


A revised calibration has been developed to address this condition. Technicians are to reprogram the Heating Ventilation and Air Conditioning (HVAC) control module with the latest software available on TIS2WEB. Refer to the Service Programming System procedures in SI. As always make sure your Tech 2 is updated with the latest software version.


Warranty Information
For vehicles repaired under warranty, use:
Labor: Operation D4707
Description: HVAC Control Head Module or Assembly Reprogramming with SPS
Labor Time: Use Published Labor Operation Time

This sounds like a bad coolant temp sensor that give computer false reading, check the coolant temp sensor connector and if it is good with no bad wires to connector then replace coolant temp sensor , when the computer gets a signal from temp sensor that engine is hot it turns fans on high speed to cool radiator and displays a/c turned off , if this truck does not have electric cooling fans then they wont run just explaining what happens depending on engine and cooling set up. replace coolant temp sensor and check connector.

Take the bottom hose off to drain sstem and makesure you refill with at least 50% antifreeze to prevent corrosion inside the engine cooling system

The impeller can fall off the water pump internally and it will not leak, but no coolant will circulate.

If you need further help, reach me via phone at https://www.6ya.com/expert/jason_e95d2f9c1ac9610d

mo me it sounds like low fuel volume i would check my lift pump

Locate the thermostat. The thermostat is in a metal housing at the end of the radiator hose where it connects to the engine.

Drain enough coolant to make the water level below the the thermostat level so that the coolant doesn't spill everywhere...

Remove the thermostat:
The housing is held down by two bolts.
Remove the bolts, remove the thermostat and scrape the gasket and sealant from the housing and the manifold.

When replacing, use Permatex #2 - non-hardening gasket sealant.

Replenish the radiator with 50/50 coolant/water mixture (re-use what you took out; don't pour down drain or on grass - kills vegetation).

Remove radiator cap and let engine warm up (look for leaks) to allow trapped air in the cooling system to escape.
Note: there may be some burping valves near the thermostat. If obvious, open them to allow air to escape.

Hope this helps!

After replacing the thermostat, you must bleed the air from the cooling system.

To bleed air from the 2.2L and 2.5L engines, remove the plug or sensor on the top of the thermostat housing. Fill the radiator with coolant until the coolant comes out the hole. Since the plug is made out of steel and the thermostat housing is aluminum, it is a good idea to apply an anti-seizing compound or Teflon® tape on the plug threads prior to installation. Install the plug and continue to fill the radiator. This will vent all trapped air from the engine.

Any trapped air in the heating system will have to be displaced by coolant. Once the cooling system is filled, with the radiator cap off, turn of the heater at it's highest setting. Start the engine and allow it to reach operating temp. You should see a drop in the coolant level as the air in the heating system is displaced by coolant. Add coolant to the proper level and replace the radiator cap.

Keep a close eye on the coolant level for at least the next couple of weeks. The cooling system is a "closed" system. Any significant decrease in coolant level indicates a problem.

If you have any questions, let me know.

Please take the time to rate this solution.

Drive safe and be warm.

clarkco

HAS TWO KNOCK SENSORS they are both under intake in valley of engine. remove intake and will see two black grommets they are under those best to replace both at same time