2006 Avalanche 2500 8.1L coolant loss, "white smoke" from tailpipe, but no exhaust fumes in coolant?

Caver Dave

Caver Dave

Just holdin' it down here in BFV
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Sons '06 Avalanche w/ 150K 8.1L started blowing white smoke from exhaust from the tailpipe on startup:

- Losing about 1/2 gal. every 100 miles
- White haze appears to diminish after warming up
- No codes
- No visible leaks

Assumed head gasket(s), BUT:
- 3 checks with (2 different kits of) color changing juice on the rad shows no exhaust fumes in the coolant (verified said juices *does* turn held at exhaust)
- *Cold* pressure test to 16# holds for 30 minutes with no drop



Kinda miffed, but know the "collective" is wicked pissah smart...
 
head gasket leak with collant going into intake port , no exhaust gas into coolant and coolant burning in CC
 
Ron said:
head gasket leak with collant going into intake port , no exhaust gas into coolant and coolant burning in CC
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Was one of my WAGs...
- But figured the "leak" would be evident when cold (parts contracted)?
- And can't cipher how a HG blows in the "coolest" section (at/near coolant passage) or ars the MLS HGs prone to that?

And before asked, I left it out in the original, but no milkshake... so no coolant getting into the oil.
 
Caver Dave said:
Was one of my WAGs...
- But figured the "leak" would be evident when cold (parts contracted)?
- And can't cipher how a HG blows in the "coolest" section (at/near coolant passage) or ars the MLS HGs prone to that?

And before asked, I left it out in the original, but no milkshake... so no coolant getting into the oil.
Click to expand...
Yep. So many ways a head gasket can fail, one test can prove all.
 
Noel said:
Compression into coolant. Coolant into compression. Etc. sounds like to me you got a case of the if it looks like a duck and sounds like a duck.
Click to expand...
Following... so even if there's no exhaust in the coolant, no coolant in the oil, cooling system holds pressure and no codes for misfires... that wouldn't rule out a roached HG?
Noel said:
Fix it before your buying converters like @mbalbritton
Click to expand...
🤑
 
Caver Dave said:
Following... so even if there's no exhaust in the coolant, no coolant in the oil, cooling system holds pressure and no codes for misfires... that wouldn't rule out a roached HG?

🤑
Click to expand...
Yes kind of lol. You’re dealing with a dry intake system. You’re smoking coolant and loosing it as well. It’s either gonna be a cracked head or bad gasket. I’d tear down check heads and replace gaskets. I’m not super familiar with the v10 but I know they are same platform.
 
Noel said:
Yes kind of lol. You’re dealing with a dry intake system. You’re smoking coolant and loosing it as well. It’s either gonna be a cracked head or bad gasket. I’d tear down check heads and replace gaskets. I’m not super familiar with the v10 but I know they are same platform.
Click to expand...
This is a GM 8.1L "big block LS V8" bro...
 
I'm ASE certified, and I say compression test it :huggy:

ASE.JPG
 
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