valve covers & Removing oil sludge buildup

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What is the best way/product to use to remove sludge buildup, to clear
the oil passageways?
I have a GM 3.8L supercharged on a 99 bonneville ssei.  I think the oil
drain passageways may be blocked, causing the oil not to drain back
quickly enough.  There is a bit of oil leaking from the TOP of the
valve covers, which seems strange. I cant see any oil elsewhere on the
It started happening a while after I started going to a quickchange and
they used penzoil 10-30W. Before I switch out the oil I want to clean
out the gunk and see if the leaks stop.


Re: valve covers & Removing oil sludge buildup

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Top engine oil leaks are usually bad gaskets or loose gaskets, PCV systems
plugged up, etc.
Or hellacious blowby.

With that sort of engine you need to change oil (good oil, not Gumzoil)
often, every 3000 miles
or so.  Use synthetic if you wish, but change it often too.  Use a good

I have had an engine or two with varnish and gum problems, and usually got
relief by adding
a good compound to the crankcase a couple hundred miles before the oil
change.  I sometimes
use Mystery Marvel Oil, but I am sure there are as good or better out there.
These are intended
to slowly dissolve gum and sludge, not knock it loose where it will cause
you a problem.

Good maintenance goes a long way.  I get the feeling that you haven't really
babied this one.

Re: valve covers & Removing oil sludge buildup wrote:
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If you can pull those valve covers you may find you need a putty knife
to clean all the build up from them. Despite how clean it may or may
not look, those oil returns can well be plugged or restricted by gunk
or pieces of stray gasket material. Use a stiff steel wire and work you
way down the passage.

Re: valve covers & Removing oil sludge buildup

Al Bundy wrote:
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what he said.  now switch to a good quality "fleet" oil like Rotella or
Delo to clean up the stuff you can't see.

good luck


replace "fly" with "com" to reply.

Re: valve covers & Removing oil sludge buildup


thanks for everyones help.  I dont drive the car very much so I it
tends to go on short trips....   it only has 60,000miles.  But I do
change the oil every 2800-3000 miles.  I stopped going ot the dealer
because they pissed me off, however they use Chevron oil of some sort
which seems to be better. Then  I started going to the pennzoil
But I just bought some mobil 1 and will change it out as soon as I have
some time.

The oil seems to pool in the depressions where the fuel injectors are,
just above the top of the valve cover.  However there is no residue of
oil from above that, just right at the gasket of the valve cover.  It
may be coming from higher up, but I cant see any residual anywhere
else...  The engine is really nice and clean otherwise.

I would like to take the covers off, except that the fuel supply lines
are over valve cover and I am not skilled enough to start removing fuel


Nate Nagel wrote:
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Re: valve covers & Removing oil sludge buildup

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Going in with Mobil 1 before you get that sucker cleaned up and the gaskets
in order is, to me, having your priorities a bit out of order.

I have no problem with anyone who wants to use Mobil 1 (although I dont use

I used to use Quaker State, before Pennzoil bought it.  When the oil
of QS apparently changed, I was forced to switch to a different brand.  I
my engine for varnish before I did it, however.

If your valve cover gaskets are loose or deteriorated, you will just
more leakage as you go about your experimentation.

Re: valve covers & Removing oil sludge buildup

If your finding oil in the depressions by the fuel injectors the Valve
Cover gaskets are shot. On my 91 the VC gaskets are like rubber bands
that fit in a slot in the lip of the VC.

Do you know anyone that works on cars themselves? Friends, co workers,
neighbors, relatives? Ask around to see where they have their cars
worked on.

As one poster mentioned it might be wise to drop the oil pan & inspect
the pick up screen. As far as I know the pan comes off easy on that
model car.

My mom has a 91 Cadillac that moves about 800 - 900 miles a year and the
oil is changed once to twice a year. No sludging here even though it
doesn't go very far. Mostly short trips of 2 - 6 miles round trip to the
store, bowling & the mall.
Every now & then I use it to run it about 25 miles or so.

Never had a problem using Penzoil on her car. I use Castrol 5 W 30 on my
Buick & 10 W 30 on the Bonneville.

Run a good quality cleaner through the engine. I've used Mystery Marvel
Oil throughout the years on my cars. Run the car on the highway for an
hour or so & get it really hot - then have the oil changed. The oil
change attendant will love that.

Good Luck

05 Park Avenue 41,000
91 Bonneville 306,670

Re: valve covers & Removing oil sludge buildup

Hi again everyone.
Thanks for the advice.  I will get the valve cover gaskets looked at
and possibly replaced.  As I mentioned, the only oil I can find on the
engine is pooling in the fuel injector depressions, which are just
above the valve covers, and it appears the oil may be coming from
there. I cant find anywhere else where there is oil above that in the
engine.  When I take the oil filler tube out and look into the front
valve cover, there seems to be a thin coating of blackish stuff, but
not as thick as I problably thought.  putting my finger in and wiping
the underside of the valve cover shows me that there is a bit of a
black coating but not globs.   Hopefully the shop mechanic can
determine if there is too much sludge and requires a flush, or if some
marvel will do.

once this is fixed I will ask you about my ongoing transmission noise!


Harry Face wrote:
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Re: valve covers & Removing oil sludge buildup

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Why? You haven't listened to anything anyone has said yet.

Re: valve covers & Removing oil sludge buildup

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Are you sure they actually changed the oil ? No matter how cheap the
oil is, with 3K changes it shouldn't gum up at all.

Re: valve covers & Removing oil sludge buildup

If sludge is a problem here , you better get the pan off and check for a
restricted oil pick up screen!
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