cracked head on Geo Tracker?

My fiancee has a 1994 Geo Tracker which burst a heater hose and
overheated, losing most of its water. After repairing the hose the
car ran fine for a week or so, but then started spewing white smoke
from the tailpipe. Figuring a blown head gasket we performed a
compression test, and first off found that the engine had overheated
so badly that it had melted the plastic ends of the sparkplug wires,
making two of them nearly impossible to remove. So that was a bad
sign to start with.

After finally removing the wires and plugs and performing the
compression test, the first thing we noticed was water spraying from
open cylinders 3 & 4. Bad sign. Cylinders 1 & 4 tested at about
180-185 lbs, but 3 & 4 were all the way up at around 240 lbs. My
guess was that the water in the cylinders was reducing the volume of
the cylinder and increasing the compression. However, after
performing the test a few times all cylinders settled down to the
175-190 range, so compression seemed OK once most of the water was
out.

We reassembled the plugs and started the engine and the car ran great,
although it still spewed white smoke when revved. After heating up it
started running poorly, although it did stay running.

Obviously water is getting in the cylinders, but the compression test
shows good compression so we're stumped. Could the head be cracked or
the head gasket bad and compression still be good? Could a crack in
the intake manifold be letting water in that way? Anyone have any
ideas here?

Sounds like you need to remove head to determine if you blew head
gasket, warped head, cracked head, or cracked block. The reason why it
runs better cold and has compression cold is once engine heats up crack
or bad gasket opens up allowing more water into chambers. I've seen
this a million times (it seems like it) whenever you badly overheat an
engine, the head needs to come off. If you keep on driving the water
will dilute the oil and eventually the water in the oil will destroy
the bearings, etc. Hopefully you'll just need to replace head gasket,
and intake, exhaust, and maybe surface the warped head.

That's more or less what we figured, so at 104K miles we're putting
the car to sleep.




On 28 Dec 2004 10:39:43 -0800, "edmechanic" >
wrote:

>Sounds like you need to remove head to determine if you blew head
>gasket, warped head, cracked head, or cracked block. The reason why it
>runs better cold and has compression cold is once engine heats up crack
>or bad gasket opens up allowing more water into chambers. I've seen
>this a million times (it seems like it) whenever you badly overheat an
>engine, the head needs to come off. If you keep on driving the water
>will dilute the oil and eventually the water in the oil will destroy
>the bearings, etc. Hopefully you'll just need to replace head gasket,
>and intake, exhaust, and maybe surface the warped head.