Hi, so I have a 1994 disco 3.9 V8 with 168k miles that is new to me for about 8 months now. I noticed a yellow-ish goo in the oil cap and the breather thing... Since I have it I only ran about 100 miles with it, and the coolant level in the expansion tank dropped maybe 1/2 inch. The engine run fine (but takes 3-4 seconds to start) and don't overheat so I'm not sure if the head gaskets may have a leak. I was also thinking that coolant may leak behind the timing cover. I checked the dipstick but no trace of coolant there.
Any suggestions where to start? I just don't want to open everything for nothing...

 

if its just in the fill cap it COULD be just from condensation buildup/ not running the engine long enough, lots of short trips only lasting a few minutes where the engine never realy gets to operating temp.

if your losing coolant might want to do a pressure test, lots of places to leak that you would not normaly notice like loose hose clamps etc

 

I checked that and no loose clamps... The only thing leaking out of the engine is oil, from the valve covers and front crankshaft seal...