oil in coolant

[Dennis Johnston]

My coolant looks like chocolate milkshake. My oil looks like oil (no cream).

Rebuild the head last season. Reassembled during the winter months. Didn't have any problems before.

Possibilities:
1) Head gasket bad or warped head.
Used a felpro composite, not metal. Surface prepped ever-so-nicely and dry. ARPs torqued to spec. Head and block checked. Car runs nicely, no smoke and compression is great.

2) Oil filter housing.
Installed the oil filter and it made a nice 'crack' when I tightened it.

I hope some of you smart guys would have some ideas on my milkshake, I'm thinking its the oil filter housing but not too sure how to diagnose. Help?

[Ryan Coft]

compression test would tell you if you've blown part of your headgasket clean out to an oil passage, hope not for your sake

cracked oil cooler would require manual inspection i think, or a coolant pressure testing may work (also tell you if you've popped your HG between a coolant passage and cylinder, but it doesn't sound like it)

[Kristopher]

If you suspect you heard a crack when spinning on the new filter then the assembly comes off relatively easy (the sandwiched part) if I recall. Remove and clean then you know.

[Andrew Brown]

i had this issue too. this is what mine was. check out the second cylinder from the bottem, you can see where oil and coolent where mixing, but not getting in the to cylinders.

[Jason Harwood]

Leak down test would be the best to find out if its the HG.

[John Hartman]

DO NOT CRANK OR TURN THE ENGINE OVER ANYMORE, until you change the oil and filter.

99% of engines that have been run on "chocholate milk"  "cafe latte", "milkshake"  etc, which is a mix of oil and coolant do not last much longer.  Of course you will hear of people who will say its perfectly fine to just change the oil and drive it but I respectfully say "nay" to that.

Change the engine oil and filter, and when you change the filter see if the big center bolt on the filter housing spin-on part is loose.  Also, if you can pressurize the cooling system with the engine off, look in the oil cooler and see if its leaking in there.

Then, don't drive the car, but you can now safely crank it over a few times for diagnostic purposes.

Leak down, compression test, pressurize the coolant and look/listen for leaks.