Oil in water resovour vw 2002 passat

This might be a cyl head gasket or oil cooler gasket on oil filter housing

Could be a bad water pump,clogged radiator.

If no external leak and the transmission fluid colour looks white, the problem belongs to the automatic gearbox oil cooler. The oil cooler has broke mixing the gearbox oil and coolant causing this milkshake. It's a small radiator core type oil / water heat exchanger. It is cracked inside and transmission oil is mixed with engine coolant. Because the transmission oil pressure is greater than engine coolant pressure, the transmission fluid level drops. See also the coolant colour inside recovery coolant reservoir inder bonnet! It could be like this:


The automatic gearbox oil cooler type oil / water heat exchanger (oil cooler):


In the picture above the transmission oil pan was removed for oil filter replacement.

The oil cooler is almost definatly the problem

The reason for this is.

Your oil pressure is normaly anywhere between 2 and 5 Bar depending on engine temp and oil type, where your water pressure is never more than 1.2 bar. Thus the oil pushes into the cooling system due to the fact that it is of higher pressure.

In the event of a head gasket leaking it will push water into the oil not the other way round causing the oil to eventually go white.

These cars are known to have problems with their oil coolers from time to time.

Most likely place for oil into coolant is oil cooler, the aluminum box that mounts between the oil filter and a flange that comes off the block.

You can see the coolant level by looking through the opaque round coolant reservoir. It should be just over the middle. There's a line indication proper level. Orange Dexcool meets the VW specification and is generally available. The rear coolant flange can warp and seep over time and leaks onto hot parts. That's probably why you smell it.

replace the oil cooler first before you change the head gasket ,but normally a 10 year old vehicle often has gasket fatigue ,not made like a good old fashioned copper head gasket ,they rarely went wrong

good likely hood that your oil cooler is leaking oil into coolant this is something you want to replace as soon as possible. you will have to flush your coolant system several times to get as much of the oil out as possible. if you wait you will have severe temp issues as well as not heat due to a clogged heater core. and that is very hard to replace. To flush system hook garden hose to the larger hose of the coolant reservoir get car up to temp. keep idle up a little. get large bucket from the smaller hose that goes into the reservoir hook small hose to it and let it empty into bucket keep hose running thru all the time. before that though replace oil cooler. also replace coolant reservoir as well. or oil will contaminate new coolant. good luck

This sounds like the oil cooler is faulty .you will need to replace this and then wash out collant system

This is probably a head gasket problem and not an oil cooler problem.

The oil cooler is fairly easy to test.

Remove the cooler from the engine but do not disconnect cooling lines and then pressurize the cooling system. You can use a radiator test tool to put pressure on the cooling system and look for leaks. If it leaks, replace it.

You may also be able to bypass the oil cooler altogether if it leaks.

The head gasket is another story.

Get a 1/4" pipe to spark plug fitting and put a male air coupling fitting in it.

Then you can charge the cylinders with air from your compressor.

Make sure each cylinder that you test is at top dead center so that the valves are closed.

If air bubbles into your coolant, you found your problem.

If air leaks out your intake you have a bad intake valve

If air leaks out your exhaust you have a bad exhaust valve etc.


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Tim