-2010 5.4L 3v
-182xxx miles
-Kooks long tube stainless headers, no cats, off-road y-pipe, magnaflow muffler
-S&B air intake
-5* custom tunes for the headers/no cats

Never had any major issues, and do all my maintenance and repairs myself. Love the truck, lots of power, don’t beat on it but do treat it like a truck, tow, etc.

It has always had some initial white smoke with a cold startup (normal) and would go away once warmed up/t-stat opens. Never overheated engine (196° on monitor all the time once warmed up), does not leak anything. Always use Mobil1 5w20 full synthetic with Motorcraft FL820S filter every 7,500 miles. Coolant looks a little cloudy in reservoir, and about 1” low from minimum line. Oil is also low, atleast 1 full quart. Oil fill cap has a lot of moisture sludge buildup and around filler neck.

The past few days it has been POURING white smoke from the exhaust, especially during acceleration, even after engine is completely warmed up. Again, temps are all still normal, no overheating.

I did just throw a full bottle of Seafoam in my gas tank about a week ago, I do this maybe once a year. And am hoping I am overthinking this, and the white smoke is coming from the seafoam....

Temps here in Michigan just plummeted also, lows around -10° at night and 10° during the day.

What do you guys suspect is going on here? Everything points to a blown head gasket.... But I feel like my coolant level would be a lot lower. I am almost due for an oil change, so I was thinking about topping off coolant reservoir with distilled water, changing oil and filter, get a full tank of fresh gas, and possibly change my spark plugs (haven’t done this yet, bought truck with 130k, not sure how old plugs are) today, and see how it runs after that.

Any help would be appreciated!

The amount of coolant that’s low/missing is very minimal, 1/2 qt of distilled water isn’t going to freeze once mixed into the cooling system.

Probably going to change the oil today and see how it looks, and fill up the tank with fresh gas.

Any thoughts on the Seafoam? Would it still be making my exhaust blow white smoke even a week later? (Same tank of gas)

So I got around to changing the oil and filter, and also replaced all 8 spark plugs. Ignition coils look to be in good shape as well. Started it up and ran very well, it was dark outside so I couldn’t really tell if it was still smoking a lot while driving.

I’ll keep an eye on the oil level (and if more water/condensation/sludge gets built up on the oil fill cap), the coolant level, and the engine temp. At this point, I’m not sure if anything is even wrong. Could just be the rest of the Seafoam burning through the fuel system.

White smoke and sludge on oil cap could be head gasket. However, just the sludge on the cap means you’re not burning off the condensation in the oil. Drive it longer at operating temps if it’s not a head gasket.

At colder temps your vehicle will sometimes have white smoke out the exhaust the whole operation cycle even up to temp. The humidity is normally low at that temp and your engine produces moisture from combustion. This will appear as white smoke in the air and when you gas it the more exhaust equals more white smoke.

Coolant ever been changed? It will be gross and cloudy if it has 180k on it and it’s due to be changed. Also at this time of year the oil fill cap will have sludge and pudding on it from short trips, you can’t use this to indicate a coolant burning issue. Here is a good video:

Appreciate all the replies. I did take off the radiator cap when truck was cold, started it up and watched for bubbles, nothing. So that tells me there’s no air in the cooling system. I may get one of those CO2 detectors and try that just to be safe.

But I do think I was overthinking all of this, and it’s just a combination of the Seafoam and these extremely low outside temperatures. I have the day off so think I’m going to take it on a nice long highway cruise to really try to burn everything through the fuel and exhaust.

I will keep you all updated, and again thank you!

the “smoke” (I’m thinking it’s more just “steam”) disipates quickly