Varnish inside valve cover, - Should I leave it alone?

[Judge2]

I was changing my PCV valve, and part of the grommet fell into the valve cover area. To remove the grommet, I took off the valve cover and found there to be significant varnish and a little bit of thicker stuff that might be called "sludge." This is on a 1996 4 cylinder with 188k miles.

While this topic has been discussed here before, the answers range from do nothing, use seafoam, use something called, Auto-rx, which I don't know about, and no clear answer. So I'll bring up the topic again.

[eyeball96]

Pics would help determine an answer to your question fer sure.

[carsrus]

If its not that bad and the cars running fine I would leave it alone. Maybe change the oil a little more often/ use some better oil.

[SexieWASD]

cleaning the valve cover will never hurt, as long as you don't leave pieces of sludge about to fall off, however if it doesn't look like any would break off and cause problems their isn't really any benefit to it.

You would probably do more good to change the oil then run it hard for 1-2k miles then change the oil again.

[Hajoca]

Could the thicker stuff be absorbed in a paper towel or rag? if it can, no worries.

Cleaning it slowly with more frequent oil change and using a higher detergent motor oil is the best way.
Look into diesel rated "multi fleet" oil like shell's Rotella 10W30, Mobil Delvac 1300 or similar.