Gas Cap Sludge

We have a 2009 4-banger with about 166,000 km. Finally got around to cleaning the MAF sensor and throttle body (both have never been cleaned before). Next up: spark plugs. Noticed oil cap has some sludge. Could this be a result of a sticky throttle body and failing spark plugs?

 

Normal

 

That’s good to hear. I thought maybe there was an incorrect mixture of air and fuel causing carbon buildup or something.

Thanks!

 

Short trips and not letting the engine burn off the byproducts of combustion.

 

You should probably change the title of the thread. because it's oil cap sludge, not gas cap sludge. I was confused how the responses related to the gas cap. now i get it, it's the oil cap.

 

Not normal.
Looks like poor quality oil that really needs changed.

 

This^^^^^^ Definitely not normal unless the engine has has a record of "extended" oil and filter changes. Shine a bright headlamp down the oil fill and take a look at the valve train. The worst I have seen on the oil fill caps on my vehicles over the years is some normal and limited white sludge build-up in the winter from moisture not burning off on short trips, or extended idling. A thirty minute trip or a warmer day will burn it off. Some carb cleaner spray should remove that.

 

Looks normal to me.

 

Looks like someone smashed a piece of chocolate fudge in there .

 

Looks like my 2009 4.0 with 145k
Oil changed every 3500

 

What's "normal", at least for me, is the lighter colored/almost white "sludge" or foamy looking shit that happens in the winter...especially after a bunch of short trips.

That dark chocolate colored (good description spitdog) sludge does not look normal....to me. Naturally, YMMV


BTW, for reference and comparison...my oil is changed every 4-5K with full synth. 240K total miles...bought at 11K, so if it was "abused" before me, it wasn't for long.

 

That's about on par with the average vehicle I see come into the shop but I believe it's largely due to lack of oil changes because the average vehicle I see is also 2-7k overdue for an oil change.

Change your oil on time and you won't have that problem, here's mine at 73k 4500-5k OCI and my 84 F250 at 300k 3-5k OCI.

 

Molto bene! That's what you want to see.