On Thu, 29 Jul 2010 21:51:34 -0700, email@example.com (blowout
I posted in here a few weeks ago about a 3800 with about 160K, which
hydrolocked overnight after running normal the previous day.
Removed the plugs and cranked it and it blew coolant out of both
banks (which I figured ruled out a head gasket).
Finally tore into it today and removed the plastic UIM, expecting to
see it burned where the EGR pipe passes through he bore in the UIM. It
appeared to be original since it had the larger diameter pipe which
pretty much is in direct contact with the bore in the plastic.
Upon inspection, I was surprised that I could see no evidence of any
such charring or burning there... Thinking it had apparently been
replaced before, I looked at the mfg date stamped into the UIM and it
was March 1998 -- the same mfg date of the car according to the door
sticker ('98 Olds Intrigue). UIM gasket looked unharmed as well.
The LIM was covered with coolant, and I was going to replace the
gaskets anyway while I was doing the upper. Upon removal of LIM the
gaskets didn't look very straight or pristine and possibly been the
cause of the problem. But to my untrained eye I find it hard to really
tell by looking at them if they had actually leaked or not.
1. It seems unusual that the UIM doesn't show any wear or signs of
failure, given the fact that they are pretty much expected to fail --
especially with that hot EGR pipe in direct contact with the plastic
bore for 160K miles. Either my untrained eye doesn't know what I'm
looking for, or there is nothing wrong with the UIM. Would it be
unreasonable to simply re-use it -- perhaps with a smaller diameter EGR
tube if available? Trying to save money here. Or could it have damage
not visible from the outside or something like that?
2. Would the LIM gaskets failing result in the condition of hydro lock
and coolant in both banks -- same as a failed UIM would?
3. Would most people feel confident ruling out a head gasket issue?
I had to wait to get the time to start on this job, as it appeared
to be rather involved, as there is a lot of stuff needing to be removed
on this car to get at the problem.
And so after doing all that I was a little bit concerned that the
problem wasn't what I was expecting at all. TIA.
My son's Bonneville had about 80k miles when we did it as a preventive
Didn't see anything wrong with the upper. No melting at all.
The LIM gaskets looked ready to fail, but who knows. We put in a new
upper, since the original design is known to fail. Dorman from Amazon.
They have it for $78. Despite some saying they always fail, you can see
they don't. Maybe it has to do with EGR operation in different cars, and
different circumstances causing a hotter tube.
Make sure you use the metal-clad LIM gaskets. The originals are known to
be failure prone. No experience with hydro-lock.
You could have possible damage, but you're in far enough now to finish
up and find out.
What I would do is re-use the old upper to get it running so you know
you have a engine that works.
Then, if you are good, decide whether to put on a new upper or roll the
I have been confident from the start that I don't have engine damage,
because of the way it let go after it was parked. I drained the oil and
there was NO trace of anti freeze in the oil. And when I removed the
LIM there was no anti-freeze in the valley below it, so lifters, etc are
I think that is pretty good advice, to re-use the upper and go from
there. I would feel more comfortable and confident re-using it,
however, if I could first install the smaller diameter EGR tube which is
available in many of the upgrade kits (new UIM's).
Does anyone know if these are available individually, or can you only
get one with the upgrade kits?