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post #1 of (permalink) Old 06-07-2007, 09:17 PM Thread Starter
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Sludge on oil dipstick

So my 258 is obviously getting tired. I has about 84K on it and has had some blow by from the rear breather for a while. Compression however is still very good on all six cylinders. Lately I have noticed a yellowish/brownish goo on the very bottom of the dipstick. I changed the oil and it shows up about 150 miles later.

What is this from? More importantly is there anything, short of a rebuild or engine swap, that I can do to minimize or eliminate the 'sludge'. I have not pulled the oil pan yet to see if it is full of the stuff because it took me forever to get that ^@$*!# to stop leaking in the first place. I once heard someone mention something about flushing the engine with sea foam or something similar.

Thanks for your comments.

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Last edited by relsner; 06-07-2007 at 09:18 PM. Reason: spell
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post #2 of (permalink) Old 06-07-2007, 11:09 PM
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I had the same stuff on the end of my dipstick when i had my 258. Found out it was the oil i was using. I was using Q so I went to Moble and it stoped. Now all use in everything is Moble.

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post #3 of (permalink) Old 06-07-2007, 11:50 PM
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It most likely means that you're getting water in the oil. It can come from blowby, coolant leak or submerging the engine. Since it comes back so quickly I'd guess coolant leak. With luck a head gasket. Without luck, a cracked head or block.

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post #4 of (permalink) Old 06-08-2007, 01:41 AM
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Make sure the PCV system is working - otherwise condensation builds up - looks like whay you describe.
Especially since you said the breather emits smoke - the crankcase should be under a slight vacuum from the PCV system.

Have a look at the inside of the oil filler cap - more of the same? Worse? Condensation rises to the highest point - usually the cap and the upper end of the dipstick.

Let us know what you find.

Change the oil - see if it continues.

If it continues, have a radiator shop pressure test the cooling system. There may be a small leak somewhere.

84 K is not old and tired - it's just barely broken in.
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post #5 of (permalink) Old 06-08-2007, 09:11 AM
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Water mixed with oil. As you say, it forms a “goo” which is not liquid. Get the engine (and the oil) hot before your next oil change so the “goo’ comes out with the oil. Otherwise the “goo” stays and mixes with the new oil. The showing up again at only 150 miles sounds like that’s what you’ve got going on.

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post #6 of (permalink) Old 06-08-2007, 10:00 AM Thread Starter
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Leak ??

Now that it has been mentioned I did recently have to add some coolant as the level seemed a bit low. What other symptoms, if any, would be present with a head gasket leak?

Where else could water get into the system? Other than driving in the rain the engine has not been exposed to any deep water.

I looked at the oil fill cap and it is not clean so it does not seem that condensation should be the issue. PCV is working well, I tested with the engine running and the valve is definitely being sucked up and considerable vacuum is present. I do get oil blowby at the rear breather. I had connected a catch bottle and the stuff being pumped out looks kind of like thick dark chocolate milk.

What about an engine flush, is this a good idea at all?

Thanks again...
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post #7 of (permalink) Old 06-08-2007, 12:46 PM
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When you take crankcase oil and water and mix them up - you get what looks like chocolate milk. That's not a good sign.

You checked to make sure there is vacuum at the valve, but that's only 1/2 of it. That vacuum has to clean the crankcase - fresh air has to get into the crankcase at another place. Then the fresh air gets sucked in and "sweeps" the fumes out by the PCV hose. If there is no place filtered fresh air can get in, you can get lots of condensation.

Try a compression test, that may tell you which cylinder is leaking fluid in. But - often a compression test may not show it. But look at the plugs as you do it. The leaker's plug will usually be cleaner looking - it's getting steam cleaned.

Take ALL the plugs out before the test - crank it over a little with white paper towels in front of the plug holes - sometimes you'll see water or anti-freeze collect on the towels.

A thought - some heater control valves use vacuum to operate the hot water valve. If the valve fails coolant can get sucked through the valve - it can be very misleading. Just look in the vacuum line to the control valve to see if it has coolant in it. It's obscure - but ---?
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