Ive had a minor coolant leak since I bought this particular truck. I have found 2 or 3 of them and fixed all. still lost coolant. couple of weeks ago I heard a hissing between the block and fire wall. I know there are two hoses back there but couldnt see well enough to find the leak. I've read tons of threads and was pretty sure I needed a HG job. well last week on the way home the old girl decided to put all my coolant in with the oil… towed it home, found a good used engine and have it home today. I was hoping to limp the old engine along this week with some blue devil or something until I can do the transplant in two weeks. well I drained the milk shake and put new oil and filter in. topped off the coolant…. and low and behold I don't even have to start the truck to get coolant in the oil. So I'll be in a loner for a couple of weeks. My question is what went? the head gaskets, slipped liner (what I think), timing cover gasket or other? curiosity has gotten the best of me and I'd like to hear some opinions

 

You won't know if you don't take it apart, but a coolant leak at the rear of the engine says to me that you have a blown HG at #7 or #8.

Sadly, engine coolant is super destructive to engine bearings, so if you dumped all of your coolant in to the engine oil, you probably did some damage to your bearings.

 

I'm sure something bad happened. I just went and got another engine as opposed to throwing good money after bad. ill tear the old engine apart after i get her back on the road. just curious about the coolant going straight into the oil with out even running the engine. don't think I've seen that on any threads. how does that happen?

 

THats something I've never heard of before. Theres got to be a direct leak between the two somewhere that it can leak wit no pressure in the lines, which is wierd.

 

If the intake gasket failed, itsnt it possible for the coolant run right into the lifter valley?

 

If you got oil in the coolant it can get in thru the valley gasket - yes.
It can also get in where the oil pump is too - if that area is going bad.

You may as well check the intake bolts for torque by taking off the plenum and making them all torque up to spec.

Would be some work.

but it is the easy button.

Worse case might be the valley gasket.

The oil goes thru the head in a little 1/4 inch or less hole.
There is no way for the oil to mix with the coolant from a bad head gasket.

Antifreeze can fall down from the intake manifold where it attaches to the head and slip under the valley gasket and get in that way.

 

I was thinking intake manifold gasket as well, it is a straight line shot to the oil pan.