5.3 vortec coolant loss

[chevyCowboy]

well i just bought an 04 Suburban z71 and drove it home from MO a 3.5hr trip of 250mi. every thing ran great never had any troubles ran right around 200* the whole trip. that was thursday, all seemed fine friday and saturday then sunday night we where coming home from my parents and the heater would not blow heat at all, got home and if i reved it up in the drive way i would get heat, looked at overflow tank and its maybe 1/2 gal low. Put a pressure tester on the system tonight and i lost 4psi in about 10 min. i opend the fill cap and there is some milky sludge in the fill neck. iv heard that these are prone to leaking coolant into oil from the intake some how dose any one have any idea?

HELP

Josh

 

[DieselCash]

Not good news!

http://www.agcoauto.com/content/news/p2_articleid/148

 

[THEFERMANATOR]

Seems to happen mostly on the 5.3's from what I have heard, and 04 is right in the middle of the worst ones. Also check the water pump closely as they can leak and then not leak.

 

[chevyCowboy]

i ve read that this water and oil that iv seen could be from condisation in the block (i fear this is not that) but an oil sample would tell me if it is glycol or just condensation wouldnt it

 

[chevyCowboy]

I had the wife leave the Burb at home today so it sat all night since i parked it after returning home from doing the pressure test. i drained a little oil out of the drain plug and this is how it looked.

Deffinatly looks like there are water bubbles in it. just to clearify the pan was dry before i used it.

 

[chevyCowboy]

iv added the gallon of coolant last week and the heater works great now. iv been thinking about the whole situation and i just remembered that the night the heat quit blowing i had turned on the rear heat. The rear heat works great now and i have not lost any coolant. how dose the rear heat work on these i know there are lines running to the back and a seperate heater core, but dose the coolant flow back there all the time or is there some sort of a valve?

 

[chevyCowboy]

ok i am still loseing coolant, i have been checking it daily but the engine oil level is never going up. i suspect that i am 1/2 gallon low again and oil is at the exact same mark on dipstick. i cannot find any external leaks what is going on here? only thing i can think of is maybe the rear heat but i dont see or smell any thing and if its in the cab im sure we would smell it

 

[littleboy]

We have one in the shop right now that we are doing head gaskets on it. I think it's an 04 also.

 

[WarWagon]

You need to step back and look at the whole picture again.

You have coolant in the oil from the drain pan. You have white sludge in the oil fill cap.

Looks to me like you are getting coolant into the engine. Coolant in the oil is the fastest way to destroy an engine there is IF you manage not to hydro lock or bend a rod first. Forget about the rear heater, etc - you got coolant pouring into the engine.

I suggest you quit driving it until you get it fixed otherwise you will be changing the engine.

Yeah, you found the reason the last owner sold it...

 

[chevyCowboy]

what im saying is i think i may have been a little to quick on the assumption that i was getting coolant into the oil. im half a gallon low on coolant again in a week and a half and the oil has level has not changed and there is no more sludge in the fill neck. The only other possibility is that i have a leak on the intake manifold (iv heard they are common) that is letting coolant into the intake and being taken into the compustion champer that way. if it was a head gasket i would be getting pressue in the cooling system, which im not. im going to get a pressure tester again and check things over very closely.

im not so sure on what i thought was water in the little bit of oil that i drained, i really only let out about a 1/8 of a cup of oil

 

[THEFERMANATOR]

Intake manifold gasket leaks are common, but not for coolant leaks. The intake on the 5.3L is a dry intake and has no coolant ports going to it, so it cannot leak coolant in.