Nasty oil cap

Poking around the engine bay looking for reasons why my coolant is slowly disappearing (different issue lol) took off my oil fill cap and this NASTY shit was all over the cap and fill tube. Getting mixed answers on here from ‘condensation from short trips and cold weather’ to ‘serious issue’

I live in Idaho, decently cold in the winter, and only live 2 miles from work. I run my truck for like 5 min in the morning before heading to work. Is this actually just from condensation or cold weather? Or possible coolant leak?

As far as my coolant issue, everything’s pointing towards a bad head gasket, is this a symptom of that possibly?

Also, the oil on the dipstick looked normal. I did an oil change 2k miles ago, the cap did NOT look like this. I’ll probably drain the oil tomorrow to get a look at it.

 

Search the forum. This is a common non-issue with the 6 banger engine due to the long fill tube.

Condensation from short trips and cold weather is the answer. Not an issue.

 

You just answered your own question.

1. you are losing coolant.

2. you are taking 2 mile trips in the cold.

if you’ve ever looked at an oil temperature gauge while driving a car you’d see it takes a 4 cylinder turbo around 5 miles to reach operating temperature.

your engine has more cylinders, more oil, a large fan that runs all the time, no turbo, and no complicated rapid warm cooling valve system like other non-simple cars.

this is why I and others have put a catch can as documented. To catch this.
My catch can worked as a catch can when I took short trips in CO. Now that I no longer do that, the catch can no longer does that.

Sig says 2006. Assuming 4L that means at least 50% chance of a blown head gasket.

 

This^

You very well could have a headgasket leak but it's very rare for a headgasket leak to show up as condensation in the oil, it may show up on an oil analysis but it would have to be pretty bad before you would see it in the oil.

A common misconception is that a failed headgasket will cause milky oil, it can but only when it gets really bad. The only times I've seen it was on engines where it was blown so bad they would barely or no longer run.

A headgasket leak on these often will show up as a misfire on cold start along with slight coolant loss.

If you have that and no external leaks you can verify it's the headgasket by pulling the plugs, pressurizing the cooling system, and looking in the cylinders with a borescope for evidence of coolant dripping.

 

Good to know. I’ll have to look into how to set up the catch can. Thanks.

Yeah I had a shop do a compression test and it didn’t drop pressure even when running at temp for like 20-30min but I was thinking about getting an inspection cam to check out inside the cylinders. I have no visible leaks, no smoke from exhaust, not overheating, no misfires. I’m sure it’s the beginning of the end for the head gasket though. My truck was built in Sept of 2005.

 

an inspection camera to stick in the plug holes is $30

block leak tester kit not much more than that. Around $30 for tool $10 for fluid.

leaking head gasket would not change compression. Compression is done by piston rings. Leaking head gasket would mean loss of coolant ingressing into the combustion chamber being burned, cleaning the pistons.

 

For sure. I’ll def peek in there with a camera.

 

Your engine has that nasty cold that is going around...

That said, I would take your truck on a good long drive and see if that helps clear (up the congestion) things up. Getting the oil up to temp and driving it 'hard' a bit will help burn off any of the gunk in the oil.

ETA: This is a good thing to do every now and then (1x/month?) with your driving conditions-short commute, cold weather.