2003 Yukon Where Is My Coolant Going?!?!?

[Marinevet]

Can I ask what coolant you all are running? I keep hearing nothing but bad things about the Dexcool that my Denali has in it now, and it's due for a change anyways probably. Did you guys go back to the regular green antifreeze, or stay with the dex cool? Thanks.

Jeremy

 

[PJS3]

I've just stuck with the dexcool all these years.

 

[sparkvark]

The 5.3L has a know issue where you can get unexplained coolant loss. Have you tried the coolant tablets that your GM dealer sells. They are a stock GM product that I believe is vegetable based. I had this problem and my neighbor who is a retired GM mechanic told me to try this. It solved my problem. Only use the GM product. The aftermarket stuff can gum up your cooling system. Good luck.

 

[Rhonda7693]

Same issue. Cracked heads. There is a tsb.

#06-06-01-019B: Information on Gradual Coolant Loss Over Time with No Evidence of Leak Found - (Jun 12, 2007)


Subject: Information on Gradual Coolant Loss Over Time With No Evidence of Leak Found


Models: 2004-2006 Buick Rainier

2001-2006 Cadillac Escalade Models

2001-2006 Chevrolet Avalanche, Blazer, Silverado, Suburban, Tahoe, TrailBlazer Models

2001-2006 GMC Envoy, Jimmy, Sierra, Yukon Models

2001-2004 Oldsmobile Bravada

2005-2006 Saab 9-7X

with 4.8L or 5.3L VORTEC® GEN III, GEN IV V8 Engine (VINs V, T, M, B, Z -- RPOs LR4, LM7, LH6, L33, L59)




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This bulletin is being revised to include engine RPO L59. Please discard Corporate Bulletin Number 06-06-01-019A (Section 06 - Engine/Propulsion System).


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Some vehicles may experience a gradual coolant loss over time. A very low percentage of cylinder head(s) manufactured with an embossed Castech logo may develop a porosity crack in a very specific area.

Inspect the cylinder head assembly to determine if the casting was manufactured by Castech. This can be accomplished by inspecting for their casting logo located on top of the intake port, under the rocker arm support rail and in the spring deck cavity portion of the cylinder head.

Important: If the cylinder head(s) are Not a Castech casting, follow normal diagnostic procedures in SI to determine the cause of the coolant loss.

 

[Mr. Krispy]

Thanks for all the great replies! Yesterday I went home and properly burped the system based on information I got from another thread.

This morning my wife too the Kon out and came back. Now, based on how it was acting over the weekend the coolant fill level in the reservoir/tank should have dropped below the cold fill mark as though on it's way to giving me another "LOW COOLANT LEVEL" error again. However, it was still at just 1/2" over the fill mark. So that's promising. We'll keep monitoring it over the rest of the week, but this is already an improvement.

God knows I hope the whole hairline cracks and such are NOT my issue...

Now on to the next development.... Smh. My hi beams and my hazard lights have stopped working suddenly. smh...

Here's the method I used to burp it the system by the way. Review and comment please.


"12 To refill the system, install the thermostat and reconnect any radiator hoses.

13 Place the heater temperature control in the maximum heat position.

14 Be sure to use the proper coolant listed in this Chapter's Specifications. Slowly fill the surge tank with the recommended mixture of antifreeze and water to the FILL COLD mark.

15 With the surge tank cap off, start the engine and let it idle for about a minute.

16 Install the cap on the surge tank, but don't tighten it down (pressure must be able to escape). Raise the engine speed to approximately 3000 rpm in 30-second cycles until the engine reaches normal operating temperature and the thermostat opens.

17 Turn the engine off and remove the surge tank cap. If there is any hissing noise coming-from the tank, wait until it stops then remove the cap.

18 Start the engine and let it idle for one minute. Add coolant to the tank until the level is 1/2-inch above the FILL COLD mark, repeat Step 16, then turn the engine off.

19 Add coolant as necessary to bring the level to 1/2-inch above the FILL COLD mark on the tank. Install the surge tank cap securely.

20 Check the cooling system for leaks."

Or just keep an eye on the overflow bucket and refill a few times until it quits "losing" coolant. It's actually just burping itself slowly. I had to add coolant to mine 3 times and since then it has been fine.

 

[PJS3]

SMH...... I finally took the truck to the dealer and had them run a diagnostic. They pressure tested the system and determined that there is a leak into the passenger side cylinders.

I need a new engine, right?

 

[PJS3]

Same issue. Cracked heads. There is a tsb.

#06-06-01-019B: Information on Gradual Coolant Loss Over Time with No Evidence of Leak Found - (Jun 12, 2007)


Subject: Information on Gradual Coolant Loss Over Time With No Evidence of Leak Found

Forgive me if this is an obvious question, but what can I do with this information? With it being a TSB does that somehow cover under a recall or a warranty or something?

 

[MidwestMike]

No recall or warranty.
GM knows that they have a common problem, but aren't covering it, just giving their techs information on how to save time fixing known issues that they sold.

There was one Castech head number that is predominate in this issue, but it has been known to occur in a few other runs.

 

[PJS3]

Welp.... So ends the effort for this vehicle. 296K miles, 11 years.... $23,000 invested total.... Not bad. I'm satisfied.

Thanks folks!

 

[MidwestMike]

But a stupid way to lose it, the luck of the draw. If you didn't get one that they built with the bad heads you would still be rolling.