Water in Oil, Bad Gasket?/Rebuild Bottom End?

[byunique]

Last weekend, I pulled the head off my Z in order to check out the head gasket. I have been losing coolant and the engine starting to get hot every time I drive the car for at least 20 minutes. After the 20 minutes, it seems the radiator is down a good gallon of water... (yeah, lots!!). I pretty much figured I had a bad head gasket. Unfortunately, when this first happened, I was coming home from the annual Motorsport Show in 06, and it was a small leak back then, where I would refill the radiator every hour or so, but it got to the point to where it is now, where I can't really drive it at all without having to worry about it losing too much water.

Anyway, here's some more observations...

After draining the oil, it came out sludgy brown color, and a sure sign that lots of water mixed in with the oil. The mixture was quite thin too, but still oily. I guess this is called emulsification, since the oil and water actually mixed!. The valve cover had tons of sludgy brown stuff in it as well, so know the upper valve train was affected as well. The head gasket didn't seem damaged as the naked eye can see. There wasn't a particular cylinder which showed it was affected. All the cylinder tops looked the same, as well as the plugs. I guess the head could have a crack in it as well, so will have that checked out. So, the leak has got to be a crack in the head or some gasket issue, but I just can't see where it's leaking.

So, what about the bottom end? I'd bet theres a ton of sludge in the pan. When a thing likes this happens, is there a need to rebuild the bottom end or at least clean it up in some way? I can certainly pull the block, take off the pan and clean as best as I can. But, not sure if a situation like this warrants tearing it all down and having new bearings/rings put in...

Thoughts on where else it could be leaking and is it necessary to rebuild the bottom end as well? I would rather not rebuild the bottom end if all necessary and get by with what I have for a while. I would like to build another motor in due time, but just not right now. (have to get ready for the Motosport Show again...

Thanks

Brandon

[byunique]

sorry, heres the head pics

[byunique]

(pistons)

http://www.brandonyu.com/z/IMG_0035_1.jpg

(head)

http://www.brandonyu.com/z/IMG_0034_1.jpg

[byunique]

(pistons)

http://www.brandonyu.com/z/IMG_0035_1.jpg

(head)

http://www.brandonyu.com/z/IMG_0034_1.jpg

So, I take back about what I said earlier...#4 looks like its a lot whiter than the others. So, it must have leaked in that area or the cylinder cracked for that piston. I forgot to mention it was burning white smoke the last time it was started, and LOTS of it.

[Pir0San]

I had a cracked head, but it would only leak when the car was running. I figured it was the head gasket, so I tried swapping it, but pulling the head off of the car made everything much worse. I took the head down to a machine shop to get it checked out, but the pressure test passed. I later found out that the head had a crack near the water jacket that would only open up as the aluminum expanded. I replaced the head, and now no more leaking. These blocks are pretty indestructible, and if you're getting only one predominately clean cylinder, I'd bet on a cracked head.

As for the water and oil mix, that happened to me too. I let the car sit for a few days, and drained the oil. Since the water and oil do not mix very well, the water and oil divided, with the oil on top of the water. When the oil was drained, only water rushed out for the most part. After draining the oil, I dropped the oil pan and de-greased/pressure washed the inside of the pan. After getting the new head I buttoned everything back up, and the car was as good as new.

Good luck, and I've been in your shoes. I know it sucks.

[byunique]

Jeremey -

I appreciate the sympathy . I guess the pressure test is really not that accurate. Wonder if there is a way for a shop to inspect it more accurately...

I take it the car has been running a while since you did the work?

[ktm]

A leak down test is more accurate than a pressure test.

[=Enigma=]

The cleaning of the #4 piston and combustion chamber pretty much give away that this is a problem of coolant leaking into the combustion chamber, as well as the "white smoke" (steam) . arse-u-ming it's not as simple as head gasket leak, my guess is a cracked head that's leaking into the intake runner on #4. It's hard to tell just from the pics, but looking at the coolant passages, there doesn't seem to be enough corrosion present to suggest a coolant passage break-through in the intake runner, but it's probably worth checking out as that usually be spotted and fixed fairly easily, unlike a cracked head.

[ktm]

Double doh.

[Pir0San]

Jeremey -

I appreciate the sympathy . I guess the pressure test is really not that accurate. Wonder if there is a way for a shop to inspect it more accurately...

I take it the car has been running a while since you did the work?

Yeah, the car has been running good, except for the bad oil control rings that the PO of the block failed to tell me about, but even with that it still runs great.

[byunique]

Thanks everybody for their in put. I will be taking the head to the shop soon to have it checked out and will post the findings here.

[byunique]

Just a update to this.... I took the head and block down to Dave Rebello http://www.rebelloracing.com and he could not find a problem with the head. There ended up being a 3" crack in the cylinder wall!!! Its a good thing that I didn't just rely on a leakdown test nor just replaced the head gasket. I personally didn't look the closely at the cylinder wall when I took the motor apart nor woud have thought to look there for any water problems. Well, lesson well learned. He said its pretty rare but has happened to one of his previous customers before. They had replaced the head, and the problem was still happening after they did the work. So, lesson learned from the pros thats for sure. Needless to say, now I am considering rebuilding the entire motor and doing a upgrade in the process