# How much oil sludge is normal?



## Barry Allen (Apr 18, 2018)

When fueling up my car I noticed the area surrounding the oil fill cap was thoroughly covered in oil vapor. I removed the fill cap to wipe up with a paper towel and I noticed some oil sludge building up in the top of the valve cover gasket. How much oil sludge is normal for this engine?


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## Carminooch (Mar 23, 2018)

Can you post a photo and your mileage? I’ll check mine. 2018 diesel w/ 32,000 miles


Sent from my iPhone using Tapatalk


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## Barry Allen (Apr 18, 2018)

Carminooch said:


> Can you post a photo and your mileage?


I'll get a Q-tip tomorrow and show you what I'm talking about.


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## Barry Allen (Apr 18, 2018)

I checked today and it turns out to not be sludge. On the left side of the opening of the oil fill there was some rough/unusual surface material that I thought was a goo but when scratching it with a screwdriver it turned out to be some kind of hardened crust collecting there. It wasn't anything major. From a quick peek inside it had appeared to be oil sludge because it was an irregular surface appearance.


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## Z71 (Jan 1, 2019)

Sludge buildup is not normal and is a sign of engine neglect, i.e. not changing oil frequently enough, or using wrong oil. I had a 1999 Mazda 626 V6 which I bought new and drove for 345k miles before getting rid of the car. I changed oil every 3k miles and there was not a sign of sludge anywhere when I changed the timing belt and valve cover gaskets at 300k miles for the last time (This was the original engine and transmission without any rebuilds or major work).


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