Lets talk about Engine Sludge.
Now, I am the 3rd owner of this 3.7.
The first owner, from the records, changed his oil at Midas about every 6 thousand miles with Valvaline or Penzoil (both oils i hate) over about at 110k mile ownership
The second owner did not record any service Nor is any shop service listed in the carfax for 23k miles. In fact there is evidence that the second owner over heated the engine more than once.
(I can't shake the feeling that the second owner just drove the heck out of it then defaulted on the loan)
Anyway,,while changing out the water pump recently i decided to clean the oil filler tube.
Let me tell you, the sludge in it was Hard, like really hard, baked on. it was literally almost the consistency of unsanded tile grout.

Trying to clean it with 91% rubbing alcohol did nothing, i tried parts cleaner but it evaporated too quickly to be of benefit.
Finally i let the part soak in a mixture of purple stuff and water, which loosened the baked on stuff enough for me to clean it with a wire brush.
But all of this got me thinking....How bad was the engine inside, the lubrication paths and heads.


As hard as this sludge was,, i can't see how adding any additive would be strong enough to break it up without harming the seals and gaskets.
I guess i need to pull a valve cover and check things out.
By the way, the intake on the PCV valve was so encrusted that it had been narrowed down to about 3mm diameter. Insteed of trying to clean it i just replaced it.
Also, it seems the 1st owner installed a K&N filter at some point, and i can't help but wonder if it added to the sludge condition in the engine because i have already cleaned the IAC and it was horribly dirty.
What are your thoughts and experiences?


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Other than some people are just smarter than others I got nothing. Really want to see what you find under the valve covers on this neglected engine.

 

I'd be mindful of running any solvents like gunk through it. With that much sludge, it may clog the pickup screen in the oil pan. Unless you do it then pull the pan right away. Start using a quality full synthetic. It may take months or years, but at least it will prevent any further buildup.

 

You have a couple choices...... Live with it as is, and use a high detergent motor oil, and it will eventually clean it up some, or, tear it down, clean it up, and put it back together..... If your oil pressure is good, I would go with the first choice....... (which is what I am doing on my truck.....)

 

One possible bright spot is that being the oil filler tube. If the 3.7's is anything like the 4.7, the tube sits high up over the engine and remains relatively cooler. Cold start moisture mixes with oil vapors and there you have a propensity for gunk buildup in the tube, or that white milky substance when you look down in it. So, hopefully that the worst of it you're seeing.

 

I concur. You can pull a cover and see what the top end looks like, but if it's significant, you're gonna want to either drop the pan, or do a very hot oil change. And definitely synthetic oil.