Rebuilt my '88 22re 11K ago. Ran like a charm until a few months ago when it began occasionally running VERY rough for about the first minute after start-up; then it would always smooth right out. Then noticed I'm losing a lot of coolant but even with a pressure test there are no leaks. Yesterday, I noticed coolant dripping from a slightly broken weld in my exhaust pipe just in front of the catalytic converter. Did I blow the head gasket? Nothing odd looking in the oil, no overheating and it still runs fine.
>>>*Evening! I have been out hunting Coyotes, they ate one of my Sheep. Funny thing is when I hunt them I never seem to see one, when I am unprepared, there they are..!
Where were we?
Oh. Coolant leak. That rough running when cold that smooths out later is a warning sign of coolant in the combustion chamber. A fairly fresh engine that is nice and snug keeps coolant from getting into the oil in large volumes, but it can weep in during cooldown and cause roughness until she warms up. Once warm, it's just steam and out the tailpipe it goes, unless thare is a LOT of coolant.
Then you have brown oil when it's a lot of it..
When the engine gets hot, the coolant turns to vapor, yep! She can show up in the PCV valve, and often on the filler cap, although on the filler cap that can be perfectly normal since there is always moisture present when the engine cools off. Not much, but enough to show up in damp weather.
Sounds like a head gasket let go, typically we look for a cylinder running hotter than it should for some reason when we see an early failure.. Gaskets fail not because of heat but because of a difference in temperature, so an air lock, poor injector, out of time, advance not fully working, no end to the possibles, you need to find it or it can repeat.
One other thing to look for...We see a lot of the older heads with pinholes in the exhaust port of #3 or less often, #4, right at the paste line about an inch or so in. Darned hard to see, look for the telltale washed streak. Pressure test will usually show that......*EB