Oil in Coolant, water in Oil. New seals?
 

1985 GSL-SE bone stock. 13b mileage unknown. Opened my oil fill cap and noticed emulsified oil on the inside of the cap. The last few times I have checked, there is condensation on the inside of the cap. I just checked the radiator and there appears to be some oil in the coolant as well. There is no heavy smoke or vapor with the engine started, just a little white smoke at start up. The temp climbed just over halfway up the gauge, which normally the temp will only climb a little passed the cold mark. I'm guessing water seal(s) is leaking, but where? I would think the coolant would get into the combustion chamber and I'd have vapor out of the exhaust. Any chance AlumaSeal and/or No Leak would work to correct this problem on a temporary basis? I have another engine that I'm looking to rebuild.

This was just posted a while back...at the bottom of this page as a matter of fact.
https://www.rx7club.com/general-rota...-neck-1030406/

I wouldn't go as far as a rebuild yet until you are sure beyond a doubt that the engine is toast.

The "mustard" looks the same, but there is also oil in the radiator, so I'm worried something is wrong internally with the motor. Also, it is running kinda warm. Where can oil and coolant mix in the engine?

Still a noob here, but oil and water only cross paths when there is a seal that has gone bad, or corrosion has occured, say like under/around a seal. I can't really think of any other reason why you'd have oil and water cross contaminating each other...

Curious...

are you "losing" antifreeze periodically?

I wouldn't use any of that "stop leak" rubbish.

Im not losing any coolant due to leaks, but possibly through the exhaust, but not much, if any. The exhaust is clear, just a touch pf white smoke at start up.

I have a 2007 jetta and it is common for a whitish sludge to appear on the oil cap. I spoke with a tech the first time I saw it because I thought I needed a new engine. I guess it's common in the winter, I didn't notice where you were from. I don't know if its common with any other motors and but its something to look into.