HELP!! Coolant in oil... NO oil in coolant

[Gremlin218]

Hi guys....
About 3 months ago I bought my first Dmax (Less then 5000miles ago) Runs like a watch... water pump started leaking (weep hole) so I replaced it... changed oil that day (just because) 100 miles 2 gallons of antifreeze magically gone? pulled the dip stick and there it was ..... Bad water pump? Anyone else had this problem??
2006 LLY Head gaskets have been done less than 20000 miles ago at the dealer... and zero issue until I put the pump in....

 

[IOWA LLY]

Since this happened after you swapped the water pump I’m going to go out on a limb and say that’s probably the cause. Start there. Use an AC delco pump this time.


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[Chevy1925]

you get all the o-rings put on and make sure none were cut as you put it in?

 

[IOWA LLY]

James, what O-Ring being cut or damaged would cause coolant to leak into the oil? Only ones I can think of would either allow coolant or oil to leak externally.


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[Chevy1925]

James, what O-Ring being cut or damaged would cause coolant to leak into the oil? Only ones I can think of would either allow coolant or oil to leak externally.


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i would think the big one that the pump uses to seal its self in the front main cover could cause this if its missing, cut, reused old, or something to that affect. in that area, there is no oil pressure to push back into the water system but water pressure can push by, go into the crank case and it up all while the weep hole never leaks. granted, i would think it could leak externally too but stranger things have happened before lol

otherwise im with you on the pump its self being bad.

 

[IOWA LLY]

I see what your saying. I would definitely think it would leak externally instead of finding its way into the crankcase. But like you said I guess stranger things have happened. Lol


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[Gremlin218]

Thanks for the replies guys, I already ordered the new pump, will have it tomorrow and put it in saturday! just wondered if I was missing something.... Or if someone else had this issue? And I am praying the pump is the problem Or I screwed something up, because the alternatives are WAY worse! Will update when its in

 

[Gremlin218]

UPDATE......
It is not the pump! Now I am completely lost..... I can't imagine anything that could possibly leak coolant into the oil when there's clearly more oil pressure (60+) then water pressure (15) makes no damn sense!?!? Anyone have a guess??

 

[IOWA LLY]

Cracked cylinder. Frost plug that is directly behind the water pump inside the front cover.

A cracked head, although it would have to be cracked in a very unusual place....

Oil cooler could also cause it. The pressure between the water pump outlet and the thermostats is greater then you realize.


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[Gremlin218]

Checked the frost plug behind the pump.... looks new, and no signs of leaking there.

Hard to believe a head but anything is possible I guess

May try oil cooler next? don't know how I'd test it... Just replace it and hope

 

[ikeG]

I just fixed an LB7 in a kodiak that consumed coolant like crazy. It was putting it into the crankcase and burning it, and would also hyrdolock occasionally. Ended up being a cylinder cracked. Had to sleeve it.