Sludge in oil cap?

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Just changed the oil in 09 Tundra. Oil cap and about 1 inch down oil neck had a beige like sludge covering.

Just curious, any thoughts?
 
That's an emulsion caused by water mixing with oil.

If you are driving short distances and not warming up the engine properly in cold conditions, this can be caused by water condensation.

Or, you may have a water leak, like a head gasket.

Also, check your PVC.
 
Condensation. Take it for a good ride to get oil hot and re-check it. Check oil on dipstick, if oil isnt cloudy on dipstick its simply condensation. I get same on my corolla. Its not a big deal, water will evaporate once it gets hot enough.
 
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Those are areas that never see oil flow (until you pour some in), so they never get cleaned. Happens with many vehicles over time. When the fill cap is directly on the valve cover (4-bangers), it's not as bad.

My old 22-RE Toyota had a baffle directly under the cap (on the valve cover) that built up a gross looking mess. The inside of the engine was spotless.
 
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Thanks for the replies.

All I do is 25 slow miles a day going 35. Doesn't get much hiway action.
 
Originally Posted By: Rolla07
Condensation. Take it for a good ride to get oil hot and re-check it. Check oil on dipstick, if oil isnt cloudy on dipstick its simply condensation. I get same on my corolla. Its not a big deal, water will evaporate once it gets hot enough.


+1
 
This happened to me every winter until I switched to full synthetic (PP or M1). It does not happen anymore. It is oil and water mixing to make a "mayo" mix.
 
Can be pretty common depending on how oil fill shaped and in cold weather. As others said it is most likely normal condensation.
 
My 4Runner does it too with the 4.0 V6. Yellow mayo/pudding because of short drives during winter. Doesn't help that we've been below 0 for about 2 weeks now and my commute to work is about 15 mins thru town.
 
If the oil fill tube extends a few inches above the valve cover, often this stuff will form.
 
Questions like this pop up every wintertime.
As said, it is condensation that forms, and since many times oil temps do not get hot enough, the water accumulates and starts to turn into a pasty sludge, especially in low flow areas.
A good highway drive every week or so (like an hour at constant highway speeds) should clear it up.
 
It happens to my E-150, and snow blower. Long oil fill tubes take a long time to heat up and boil the condensation off. Nothing to worry about, OTOH if sludge found its way up there you'd have problems.
 
First and foremost, it's not "Sludge", as we know it........Like all have said, it's a form of condensate.
Very common on my Jeep with the Oil Fill tube elevated about 4 inches above the valve cover.
Weather like this prompts me to check it when I go through my Bi-weekly Under-the-Hood Checks.
A quick wipe out with a clean, dry rag and off I go........
 
It should be "normal," but there are some things to keep in mind, since in some scenarios, it's not normal. I get a bit of I short trip my G37, but that's not too terribly common. Now, a bad PCV will do it, too.

Back in the day, my F-150 would do it no matter how long of trips I took. It never moved for less than 100 miles at a time. The PCV passed the little tests you can do with them. I changed the PCV, though, anyhow, with an OEM one, and the condensation disappeared immediately and permanently.
 
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