What will make the oil from the engine go into cooling system on a Isuzu Rodeo 97 with 3.2 v6 engine?

So far the engine is not overheating and still strong like before and the oil in the engine still clean, no water in it. Is there anything I am missing? Let me know. Thanks.What will make the oil from the engine go into cooling system on a Isuzu Rodeo 97 with 3.2 v6 engine?
Bad head or head gasket.What will make the oil from the engine go into cooling system on a Isuzu Rodeo 97 with 3.2 v6 engine?
it has to be a blown head gasket
Are you sure it's engine oil or trans fluid? Trans fluid can get into the coolant from a leaking trans cooler in the radiator and vice versa coolant into trans fluid. Not very common but not unheard of. Pressure test the cooling system and check the trans cooler in the radiator for internal leaks by removing the cooler lines from the radiator and see if any coolant comes out of the fittings for them on the radiator when you pressure test it. If the trans cooler is leaking, you'll have to flush the trans and cooling system as well as replace the radiator.
Could be the intake gaskets.





If it has an oil cooler in the radiator that could also be leaking
You may have a slightly warped head, causing the head gasket to leak. Rent a torque wrench (if you don't already have one) Get a copy of the head bolt torque sequence from the Isuzu dealer. Make sure the engine is nice and warm. Remove the valve cover. Following the bolt sequence, loosen and re-tighten each cylinder head bolt one at a time. Do the same thing with the intake manifold bolts. These also have an installation sequence. This will usually straighten out the head and re-seal the gasket. If you have been using the ';green'; stuff for coolant, flush and clean out the entire cooling system and use Audi or Mercedes coolant. The ';green'; stuff will eventually eat holes through aluminum heads like Swiss cheese. These other coolants have special formulas that prevent this problem. Also, remove and clean your oil pressure relief valve, if it is easily accessible. (ask where it is at the dealer) If it sticks open, too much oil pressure can cause oil to ooze from the oil passageway in the head gasket into the water passageway. Begin this whole process with a nice engine bay steam cleaning. Good Luck!!
A blown head gasket or cracked head might do that. Also if you have an automatic transmission you might get ATF into the coolant via the radiator.