What is this

I’ve been smelling oil at startup for a while, so I was crawling around under the truck. Found this and I have no clue what it is lol.

It’s like a weird crystallized liquid on the rubber thing between rear of engine and trans.

 

OH Crap...

 

Can't tell. The red coolant will grow crustys when there's a leak.

 

I don't believe oil or ATF can crystalize. Coolant will crust up. How's your oil? Pull the cap lately? Oil change? If your oil is fine, I'd start looking forward of the oil pan for coolant leaks. Water pump? Lower Radiator?

 

Crystalized? Or just something like oil so filled with dirt you can wipe it off together?

 

been checking oil regularly, oil was changed ~2k miles ago, and it still looks good and smells fine. checked lower radiator hose today, and no leakage there. Did not check water pump so ill give that a look.

 

I also want to mention this showed up after I noticed a tiny seep around the oil pan area and threw in some atp-205. Could it be the stop leaks fault?

 

That's a good bet.

I have no experience with stop leak chems but if it were me, I'd look into doing a flush, drain and fill, another flush and then drop oil pan and re-seal with toyota FIPG. Then fill oil and monitor for leaks.