Chocolate milk in radiator reservoir 2007 CX-9

Hi guys, So two days ago I notice something leaking from my 2007 Mazda it was coming for the radiator resorvoir my temp gauge begins to rise so I turned off the car and get it towed to my indi,
Inmidaly I was thinking the water pump was the culprit but...

1- oil in deepstick seen fine (oil missing of course) but it is clean oil, oil inside the engine looks good too
2- tramsmiision fluid looks good too
3- radiator and reservoir are full of this chocolate milk fluid , coolant and oil mix I suppose

My indi told me it maybe be my engine oil cooler
My question is does the 2007 cx-9 have an engine oil cooler? If yes can it be my problem?
My indi haven't still looked at my car

The 2012 CX-9 does indeed have an oil to coolant cooler near the oil filter so I would assume yours does too. I would think a leak here is unlikely but I also think a oil to coolant leak is more unlikely from the water pump. I would think the coolant would leak into the oil if the water pump goes bad.

Thanks guys, my indi just call me to tell me my engine is ok, there is no coolant in there so the water pump has not failed, the 2007 cx9 indeed have an "engine oil cooler" near the oil Filter, what kind of damage can allow coolant and oil get mixing in there...

If my indi is right Im lucky, Now I need to buy a new engine oil cooler and radiator I'll be back to let you know the details

Picture of my old engine oil cooler attached

if both your engine oil and your transmission fluid look good,

then I think you're right, it's an engine oil cooler failure, I don't think it will be an expensive or difficult repair, shold be straightforward for your indie shop to fix. A lot better than an engine or transmission rebuild.

I found this online that you may find interesting..... http://www.ford-trucks.com/forums/1421821-oil-filter-full-of-coolant.html

keep us posted, thanks.

FelixRT what was the outcome of the replacement oil cooler? did this solve the problem with your cx-9. How much did this repair come out too. I am going to check mine before it gives me any problems. I noticed on the pic that it is rusty and dirty so I will definitely be checking mine as I live in the northeast where this part can easily rust and cause problems.

My Indi mechanic is 100% sure the problem is fixed, I was told to drive the truck as much as I can for a week before doing a last coolant flush
The hardest part is to clean out the cooling system coolant/oil mix is a nightmare to clean
Almost two days cleaning and counting

I need more days of driving and cleaning to know for sure if the problem is gone, heat and engine agitation is what I need now

What I'm doing is driving 15 to 20 miles them disconnecting and cleaning the reservoir coolant tank with tap water and degreaser (oil will be always on top) so it's easy to see, then I refill with desttilled water each time I clean there is less oil in the tank and no more overheating, engine oil and transmission oil looks good so so far my indi is right

New OEM Oil cooler $106
New OEM Oil cooler O-Rings $42
New radiator $145
New thermostat $7
New thermostat seal $7

Labor $250

Will be back next Monday and let you know
Sorry for my bad English
By the way my check engine light turn on after putting all back together disconnecting the battery for 5 minutes fixed it

Hi everyone,

I read this forum, and I have doubt. Also, I saw a lot of article and texts about upcoming Mazda RX9 car. Many of them suggest that future RX9 coming with Wankel engine. So, does anyone know a lot of more about it?

http://digestcars.com/2019-mazda-rx-9/

Update:

It turned out to be my oil cooler it went out at 100k miles