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2009 Mazda5 Leaking Oil Cooler

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2009 Mazda 5 GT
Noticed some steadily increasing oil drips in the garage from my 2009 Mazda5 2.3. This car has 180K miles and the spin-on style filter if that makes any difference. A quick peek underneath shows lots of oil around what looks like where the oil filter adapter bolts to the block.

All my research points towards a leaking oil cooler which sits on top of the oil filter adapter. To cover my bases, I pulled the trigger on a kit from ebay that includes the updated OEM cooler, larger center bolt and adapter gasket.

There aren't a lot of good videos out there but it seems like I need to drain oil, drain coolant, unbolt the adapter from block, switch out the cooler, adapter gasket, and then refill/burp.

Any other tips or gotcha's from those that have tackled this before? All advice is appreciated, otherwise I'll report back in ~ a week when it's complete.
 
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92 MX-3; 18 CX-5
Small tips: You should be able to get away without draining coolant. Some needle nose vise grips - or if you want to invest in some hose pinch pliers (same idea) can be used to pinch the coolant hose to / from the oil cooler.
If you recently changed oil you could also simply put a drain pan under the oil filter and only refill as needed after pulling the oil filter off. Since the engine is not running you will not lose all of your oil by removing the filter.
You might use silicone grease or assembly lube to hold the new gasket in place while you put the cooler back in place.
I have not done this to a 2.3 Mazda engine, but on others the oil cooler is sealed to the engine by a nitrile (rubber) o-ring or gasket of some shape. In many cases you can simply pull the cooler away and sneak a new gasket in place.
 
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2009 Mazda 5 GT
In many cases you can simply pull the cooler away and sneak a new gasket in place.
I get the impression that the gasket is built into the cooler, and that they redesigned them so this doesn't happen again.

Oil change is due and coolant is 2.5 years old so I don't mind changing them both out during the job.

Still driving the van in the meantime, only lost about 1/2 a quart in the past 2 weeks.
 
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92 MX-3; 18 CX-5
Sounds good. But even if you do drain oil and coolant expect to need to catch both coolant and oil when you disassemble the oil cooler.
The gasket between the oil cooler and oil filter housing is, in fact, separate. No harm in replacing everything that came with the kit. By any chance did it also include the gasket between the engine and oil filter housing?
 
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2009 Mazda 5 GT
Yes the housing to engine gasket is included.
Thanks for the heads up on catching all the fluid, trying to minimize the mess as much as possible.
 
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2009 Mazda 5 GT
New oil cooler and filter housing gasket install went well this weekend, no more leaks.
After teardown i'm not totally sure it was the oil cooler that was leaking though, think it was actually the oil filter housing gasket. But after reading how common the oil cooler failure was, I'm still glad I replaced it.

The car overheated on my first test drive though because I don't think I purged all the air out of the coolant system. As a bonus I lost the coolant overflow cap at the same time so I'm using a random cap from the kitchen until I can get a replacement.

What's weird is I thought I purged the air because I ran the car afterwards w/ the radiator cap off but the coolant level never dropped, strange. Will have to give it another try tonight.

edit: Added more coolant, drove it around for a few minutes, added more after it cooled down and it's tip-top now.
 
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92 MX-3; 18 CX-5
Congrats on the successful repair. I'm glad the air in the coolant system is working its way out. Keep an eye on coolant level for the next week or so. If you think you'll do this work often there are a couple of tools that will help greatly. The first is a spill free fill funnel first made by Lisle. These things have probably 1/2 gallon capacity so you can get the fluid in the fill funnel to be the highest point of the coolant system and can idle the car through a couple of heat cycles (hot enough to get good cabin heat and for the thermostat to open). Tip: Force a high idle of 2500 - 3000 rpm for several minutes while waiting for the thermostat to open. The higher idle will force more air out and combined with the open funnel the air has somewhere to go. For 20 - $25 the spill proof funnel is cheap insurance to getting the air out of your coolant system to avoid overheating.
The other tool is a vacuum coolant filler and cost close to $100. For some cars it is impossible to get rid of the air with a simple funnel. The vacuum filler will first create a vacuum in the coolant system and use that vacuum to fill the system with coolant. If you continue to have overheating or poor heat into the cabin then you can consider making the investment or requesting help from a shop to do a vacuum fill.
 

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