Unless the car is completely shot,
people seem to recommend doing a quick and dirty engine flush and oil
change. I'm not convinced these engines could cope with so called
"flushing oil" due to the turbo and the engine having wear on it.
So in my thoughts its best done with a 5w30 or 5w40 Semi-Synth that you
can get fairly cheaply. A short term (15 minute) flush additive
is often recommended especially if you think the engine has sludge as
it hopefully clean some of the bits you cannot inspect. Some
people would leave the old filter on after this oil change but I think its a flase economy
since a) if the engine is sludged or dirty the old filter may be fully
contaminated already and b) if the new oil liberates more sludge and
dirt then even a good filter could get overwelmed. Shopping
around a filter is less that £6.
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This oil can be left in the car for a
few
miles or days or minutes as you think best. As we've used
normal oil that is in specification for the vehicle, and have drained
the flushing agent, all we are doing is running the engine with clean
oil for a short while.
I carried out about the maximum number
of inspection & cleaning steps that you can without removing
anything complex from the vehicle. So there are a number of
separate tasks below.
Sump Drop - Access
Getting to the sump to remove even its
bolts can be challenging. The exact challenges vary a little by
model and year, but the exhaust, the subframe and the curse of GM all
impede the process.
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Some instructions advice partially releasing the subframe to lower that
rather than boosting the engine on its mountings. It all depends
which parts you feel bravest with. The sump is in a very tight
gap at the timing cover end.
Sump Drop
Once we have reasonable access its only
a matter of undoing loads of bolts. With the increased gap
between the engine and subframe there is only one of the bols which
cannot be reached with a normal socket wrench (and extensions).
There are lots of images here of the inspection & cleaning.
Its usually only on Aero's fed only on quality Fully Synthetic that
everything is clean when you take it apart. There is nearly always a
random seeming piece of metal in the sump! Its almost like the idea
that a empty purse should never be gifted.
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Cam Cover
If the bottom is dirty then its
especially important to check inside the Cam Cover. The only cost
in this is that the gasket set should be replaced when you have it
open.
I'm unclear whether you
can sometimes safely reuse the gasket, if say you only fitted it
recently.
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Oil Cooler
Although we drained the oil (twice) the
oil in the cooler is not directly affected. If we are lucky the
First Oil Change will have mixed with the original oil in the cooler
(and its pipes) and diluted the worst. The only cost on this is a
little more clean oil will be needed when we fill up again, and its
recommended that you fit (or atleast have) new o-rings.
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Warning: One new o-ring got crushed and failed during assembly so its
best to have some spare o-rings whether old or new.
Oil Sender
There is a possibility that the Oil
Pressure Sender itself might be giving false readings due to sludge
particles. There is also some feeling in the forums that the
sender often fails after about seven years. Its cheap enough but
quite difficult to access.
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Turbo Oil Inlet
One of the worst places to get a build
up of sludge is on the way to the turbo. Checking out this pipe
only involves the cost of new gaskets and seals. It is fairly
fiddly to remove and harder still to put back as the connection for the
exhaust manifold gets in the way. Its worth doing though.
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Problems Afterwards