On Sun, Nov 30, 2014 at 5:18 PM, Mark Watson <watsonm05@comcast.net> wrote:
> Folks,
>
> I'm appealing to the shop-talk group wisdom on this one. Earlier this
> year my in-laws gave us their 1995 Buick Century with the 3.1l V6. It was
> Grammy's car with only 105k miles - she can't drive anymore which is why we
> got it. It's I really good shape except for the coolant in the oil problem.
> When we got it the thermostat wasn't working so I put one in. After that it
> started losing coolant. The radiator had a leak at one tank seam (aluminum
> core with plastic tanks) so I replaced it. Still losing coolant but not
> externally - you guessed it - it was leaking into the oil. My final test
> before taking anything apart was to pressurize the cooling system with the
> oil drain plug removed and coolant basically ran out directly correlated to
> the pressure. Apparently this engine is known for having intake gasket
> issues. I pulled everything off and it doesn't look good. The oil looks
> like a gross milkshake.
>
> The question - I don't want to replace/rebuild the engine if I can help
> it. I figure if I can replace the gaskets (parts roughly $150, my labor -
> priceless) and get enough life out of it I'll be coming out ahead!
>
I did a bunch of these a long time ago, when the piece of crap engine
was a current thing.
As I recall, the job isn't terribly hard, just big. Six or seven
hours, flat rate, and I never got fast at it them. Lots of stuff to
take off to get to the manifolds, lots of stuff to put back. We never
did anything special for cleaning the engines, just drain the oil, and
change it after the engine has come up to temperature a few times.
(We usually had people come back for an oil change in a week.)
A few tips: get the shop manual. Or at least copy the relevant bits
from a library copy.
Second, the bolts holding the manifolds (upper and lower) are
different lengths in different positions. Keep them straight, or
you'll regret it. The pushrods are similarly different, and you'll
ruin the engine if you screw them up.
third, there are little plastic locating pins on gaskets (one for each
port, I think). They break off, and if you don't dig them out of
their holes, the new gasket won't go on right.
Also: there are different versions of the gasket for the 3.1 and the
3.4, and possibly for different versions of the motors. Get the right
one. Order by vin, if you're confident the engine is original. They
look a lot alike, but they're not interchangeable. I'd do some
checking to find the best gaskets for these these days, the orignal GM
design is seriously sub-optimal.
And there are lots of things you'll be taking apart. It's a good time
to replace the serpentine belt, for instance, since it has to come
off. I'd probably do the plugs, too, at 100K, unless you know they're
new.
We never did anything special for cleaning the engines, just drain the
oil, and change it after the engine has come up to temperature a few
times.
--
David Scheidt
dmscheidt@gmail.com
_______________________________________________
Shop-talk@autox.team.net
Archive: http://www.team.net/archive
|