I have a slow coolant leak ( 1 gallon in 700-800 miles) . The system holds pressure. I pressure tested it by putting a tire valve in reservoir cap, found two week spots where hoses connects, fixed that but leak remained. Then I used fl dye and black light to check but no deal, could not locate where the coolant goes.

However I do see brown creamy sludge on dip stick o ring now and then. There are also few tiny droplets of water on dip stick shaft,not much but you can see a thin film of water on oil. There is no such deposit on oil cap and it looks clean except the oil.The oil is clean as such.
Coolant also looks clean.Flame trap does have such deposits.

So when people say milky oil , is that milkiness distributed throughout the oil or is it minor as in my case.In short does my gasket leak . I have not seen any bubbles in coolant reservoir when the car starts.Exhaust gasses are colourless as such. Spark plugs are normal sooty not super clean as I would imagine a steam wash could do.

What other symtoms should be there.

Regards,
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DD-1990 240 DL SW M47II FI 3.1 234 K miles

For $20-$25 you can have a sample of your engine oil professionally tested to detect signs of antifreeze contamination. This method is far more sensitive than other cruder methods.

I use Blackstone-labs.com for oil testing.

What you describe on the dipstick sounds like normal result of condensation and short trips. A real pressure test uses a guage to observe if the sysytem can hold pressure as well as help to find the leak. After repair of the two leaks you really need to see if it will hold pressure. You can borrow a pressure tester at no charge from Advance auto.
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David Hunter

Thanks . Recently I undertook a long trip of around 1500 miles and I noticed that even after daily driving for 5-6 hours that brown sludge was forming around the o ring. I will get the pressure tester.
Regards,
Gopesh
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DD-1990 240 DL SW M47II FI 3.1 234 K miles

I would start by draining the oil and let it sit covered up for a bit. If you do have water in the oil it will separate if you give it a bit of quite still time.

There is also the sizzle test and this does work. Put on the Safety Glasses, get a pair of pliers, and a teaspoon. Put several drops of oil in the very middle, do not dip the spoon in the oil (oil and fire do mix). Hold the spoon over a flame like say a propane torch and listen for a popping or sizzling sound after couple of seconds. Water will boil at a much lower temperature than oil and you will know very quickly if there is water mixed in.

Before you tear into a head gasket looking for the leak, I would consider getting the cooling system pressure tested by a pro. Lots of places for water to slowly leak like the thermostat housing and the heater hoses.

Good Luck,

Paul

Thanks Paul. Both the tests can be done,Oil change time is also near, may be it is time to take it to pro.Heater hoses and heater side parts are the only ones which are old and have not been replaced, I have not really seen the end which goes to the block and only checked for leak with fingers.Lets see.
Regards,
Gopesh
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DD-1990 240 DL SW M47II FI 3.1 234 K miles