So I went to change my oil to the rotella and the cap had milky slime in it and saw some water vapor coming out of the top. The exhaust is not white and the dipstick does not look milky. I thought I might try a half canister of silver seal but does this sound like a head gasket going TU?

 

Before you start adding (in my opinion) sketchy fixes for a blown head gasket, verify that you actually have a problem. Any time I have added oil to a hot engine, I have seen s bit of vapor coming out of the fill hole in the head so this may be totally normal.

First, are you loosing any coolant? And if you are, confirm that you are loosing it in the head and not from something simple/common like a failing water pump or throttle plate gasket.

Normally if you are pushing coolant into the crankcase, you can see it on the dipstick.

 

Have you been loosing coolant or adding?

I'd not rush to judgement on having any issue unless you are.

Some condensation on the cap is not that unusual, especially if you live in a climate where there's a lot of humidity or temperature swings or you make a lot of short juants, where the engine never reaches operating temperatures (evaporating moisture in the crankcase area).

I certainly wouldn't add any type of additive...until I'd watched/diagnosed the issue more thoroughly. If you don't see white smoke on initial start up or smell a sweet smell at the exhaust, again, just watch your fluid levels and go from there.

Brian. (Fleet mechanic for 39 years)

 

This is a disco that I picked up after it sat for almost 2 years so that may be the issue. I changed the oil out and will watch it.