99 Yukon Antifreeze in oil

[74Monte]

Update: Mechanic says engine is bad.
Will sell for $1500.00 OBO.
I have a 99 Yukon with Antifreeze in oil. Found an old school mechanic to check it for $50.00, but he wants to get it up to operating temp to check for exhaust gasses in radiator.
Question is: with that much water in oil is there a chance it could blow motor?
It was running fine when I found it, just barely overheated about half on gauge.
Checked oil and it was 6 or seven inches above full on stick, very milky looking.
By the way it was running fine.

 

[OR VietVet]

If it is that bad the gasses should show quickly but I would just do a compression test first with all plugs removed.

 

[Marky Dissod]

I have a 99 Yukon with antifreeze in oil.
Found an old school mechanic to check it for $50.00, but he wants to get it up to operating temp to check for exhaust gasses in radiator.
Question is: with that much water in oil is there a chance it could blow motor?
It was running fine when I found it, just barely overheated about half on gauge.
Checked oil and it was 6 or seven inches above full on stick, very milky looking.
By the way it was running fine.

My broke@$$ 'gasses in radiator' test:
Be sure your engine and cooling system have cooled down to ambient temp.
Remove coolant reservoir cap, start engine, observe open reservoir:
if you see bubbles, your radiator is gassy (although I can't tell which kind).
FREE!

"with that much water in oil, is there a chance it could blow motor?"
YES. The odds are going up even as we speak.
The odds go up more quickly while the engine runs using antifreeze as a lubricant.
It's NOT running fine. The antifreeze is also breaking down the oil.

 

[exp500]

You will have to change lower intake manifold gaskets, then test for cracked heads if it still has problems.
"Do Not Start it" Antifreeze strips metal from engine bearings.

 

[strutaeng]

Ya. I had a 4.3 on my 99 Silverado NBS develop low oil pressure shortly after replacing intake manifold gaskets. Either the coolant wiped out the bearings, or something got into the engine when I replaced the gaskets (engine sat a few weeks because I couldn't figure out how to stab the distributor and had wait on my mechanic). Or it could have been just pure coincidence. It was already a high mileage engine so who knows.

That engine engine eventually got replaced with a LS 5.3

 

[Eman85]

Save your 50 and find someone with a radiator pressure tester. I wouldn't run the motor with that much water in the oil.

 

[east302]

Since it’s been sitting, have you pulled the plugs to see if coolant comes out?