Hi, 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 engine. 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.
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 filter.
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.
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.
Al Bundy wrote:
what he said. now switch to a good quality "fleet" oil like Rotella or Delo to clean up the stuff you can't see.
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 quickchange. 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 lines..
Nate Nagel wrote:
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 it).
I used to use Quaker State, before Pennzoil bought it. When the oil chemistry of QS apparently changed, I was forced to switch to a different brand. I treated my engine for varnish before I did it, however.
If your valve cover gaskets are loose or deteriorated, you will just precipitate more leakage as you go about your experimentation.
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.
harryface 05 Park Avenue 41,000 91 Bonneville 306,670
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:
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.