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Sand-like grit under valve cover after a long trip? Any idea what this is?

This is regarding a strange occurrence in my wife’s 2004 Toyota Sienna. We took her van on a 7,000 cross-country journey in June and July of this year, right in the middle of the heat wave. I used synthetic oil, 5W-30 as recommended by Toyota, and everything seemed to be fine. The problem came after I had the oil changed by Jiffy Lube in Denver, CO before my 1700 mile trip home to Washington, DC. Jiffy Lube costs a bundle when you use synthetic so I had them put in petroleum-based 5W-30 oil, knowing I would change it when I got home. During trip home (850 miles/day) I passed through temperatures as high as 110 degrees. When I got back and went to change the oil I noticed what looked like sand in the valve cover area where oil is added. I was able to scrape some out and it and rubbed it between my fingers, and it had the consistency of grit. My question is what is it, and should I be concerned? I changed the oil, and again used synthetic. Did the heat cause the petroleum based oil to boil and then crystallize like sugar? What can I do to get rid of it? Thanks.

There is an interesting thread on this forum written by a Jiffy-Lube employee…

It might be worth the effort to remove the valve cover for a closer inspection…

Check to see if you have an air filter. If so, does it fit properly?

Some cars use the engines air filter to clean crankcase ventilation air and some have their own separate filter…Be sure the entire crankcase ventilation system is properly connected and filtered…

I’m a little dense so are you talking about on the outside of the engine valve cover or inside, or around the filler tube? If its all outside, I think the kid was just a little sloppy with the oil and dirt has collected. If its inside, sounds like you do 5000 mile oil changes right, so no sludging problem? Maybe the kid checked the air filter and didn’t get it on solid again. If its all on the outside, just cleaning with engine cleaner should do. Remember it may be 110 outside but your engine is always 220 degrees regardless of the outside temp and oil is designed for that temp.

Grit and dirt will get under the cap where you add oil, but it should be confined to the area outside the cap’s gasket. When you remove the cap to add oil, you might inadvertently let some of the grit a littler closer to the edge of the hole. I see this on all my vehicles, especially after planting time or harvest time when the big farm implements kick up all the dust.

I would try to get as much of this out of the engine as possible, but if any gets down on top of the head, it should just get flushed into the oil pan and eventually trapped in the oil filter. I’m pretty sure you just picked this up along the way during your road trip.