What causes engine oil to get into the antifreeze reservoir?

Antifreeze in the oil of any engine means there is a crack in the head gasket, or worse, in the block.

HEadgasket failure, internal oil cooler leak.

if there is engine oil in the antifreeze generally indicates a cracked head on the engine

A head gasket is leaking or the Head is cracked.

A bad head gasket is the most common cause of antifreeze mixing in the oil. The antifreeze will dilute the oil and it will eventually cause your engine to seize up.

If there is motor oil in the antifreeze reservoir there is a good chance there is also antifreeze in the motor oil. This condition is probably the result of a bad head gasket or a cracked head. Antifreeze mixing with motor oil is a recipe for disaster for the engine. Have a trusted mechanic diagnose the situation soon as possible to hopefully avoid even more costly repairs.

On the oil pan reservoir mounted on the bottom of the engine block. On the oil pan reservoir mounted on the bottom of the engine block.

Look at the oil on the dipstick. If you have antifreeze leaking into the crankcase the oil will be milky.

Blown headgasket or an idiot pouring oil in the wrong hole.

If it is motor oil in the anti freeze, then it is either a cracked head, cracked engine block, or a head gasket blown. If it is transmission fluid in your antifreeze, then the radiator is leaking from the transmission cooler ----- although usually that would cause antifreeze to be in your transmission fluid.

Intake gaskets have failed.

Not as long as you put the proper fluid into the proper place such as, motor oil into the engine, gasoline in the fuel tank, antifreeze in the cooling system reservoir, transmission fluid in the transmission, brake fluid in the brake system reservoir, power steering fluid in the power steering reservoir, windshield washer fluid in the windshield washer fluid reservoir and don't forget to put blinker fluid in the blinkers! :)

the engine is burning oil. blue smoke oil white smoke antifreeze black smoke excess fuel

That means that there is engine coolant / antifreeze leaking into the engine and mixing with the engine oil. You must have an 1997---2000 modal V-8 or V-6 engine. It is very common for the intake gasket to leak coolant into the engine oil on those engines. Are you sure it did not freeze and crack the engine block ?? If you know that it had enough antifreeze in it not to freeze, Then you may get lucky and flush the engine oil and replace the oil filter several times AFTER you replace the intake gasket. OIL and ANTIFREEZE don't mix well and the antifreeze will destroy the engine BEARINGS.

NO!!!! do not do this, oil is oil, transmission fluid is transmission fluid, and antifreeze is antifreeze, do not mix any of these, it can perminately damage your engine.

if there is oil in the coolant system it could be a crack in the intake, a ruined intake gasket, a cracked cylinder head

On a 2007 Ford Expedition : The engine oil dipstick is on the drivers side of the engine near the engine coolant reservoir and the brake fluid reservoir

vehicle will overheat. just dump the oil and antifreeze , flush engine and refill with clean oil

NO ! ! - Absolutely NOT. Don't even run the engine. -Drain the oil and remove pan. Make sure all antifreeze is out of your engine before re-filling with oil.

No. Antifreeze should not mix with engine oil in any vehicle.

If you start and warm up your engine: 1) The oil gets very foamy and mucky, and does not circulate through the engine properly. 2) The water in the antifreeze can heat up until it turns to steam, which expands with great force, and breaks some part of the engine. It's best to have the oil changed. That will empty the engine of the oil and antifreeze mix.

First DON'T START THE ENGINE If you start the engine the antifreeze will be in the oil filter also Drain the oil out of the oil pan Take some new oil and pour it into the engine a few times and just let it drain out of the engine oil pan Replace the engine oil pan drain plug and then put the proper type of engine oil in ( less the amount the engine oil filter holds ) If you haven't started the engine you should be okay

When antifreeze is poured into your oil, it weakens your oil cause it to break down prematurely and can cause your engine to fail by spinning an engine bearing and even smoke. This is also a sign of a blown head gasket.

You could have a cracked engine block.

It depends on the fluid. Antifreeze is a different color from engine oil.