Own an '08-'10 Mazda with a 2.3L? Watch for sudden oil leak from oil cooler!

[LeeH]

I bought a used 2009 Mazda5 from a small car lot as an upgrade from my 2006. Went from '06 Touring with 78K miles to '09 Grand Touring with 47K miles. It also meant lots of better stuff - rear air, 5 speed auto instead of 4 speed, aux input on stereo, passenger side arm rest, HID lights, leather... considering upgrade in year, miles, and equipment, I thought the $4K difference was reasonable.

Car looked great on the lot. Other than cheap, noisy tires, it drove great. The lot was gravel, so I didn't notice any leaks. The first time I backed it out of my driveway after the trip home from the dealer, I saw a small spot. Hmmm. A strut on my 2006 was leaking badly so I really didn't pay that much attention. When I backed out to take my daughter to school on Friday, she pointed out a fairly large puddle. Yikes!

Oil was at the very bottom of the dip stick. After getting the car up on the ramps it looked like the oil was coming from the top of the oil filter housing. Some Googling revealed this to be a fairly common problem. Seems that in 2008, Mazda added an oil cooler to the oil filter housing. Not sure about prior years. The seal on mine failed. Replace the gasket? NOPE! Only way to fix it is with a new oil cooler - a $400 part!

I haven't even talked to the dealer who sold me the car yet. I'm hoping they'll pay for the part since I took care of the installation. What bothered me was that the parts counter folks had plenty of these in stock and mentioned that a couple of months ago there was actually a shortage of the coolers. They were just instructing their customers to fill up the oil every day until the parts came in. I found plenty of discussions about the seals on these coolers failing on various bulletin boards. Don't know when mine started leaking, but it would have run out of oil pretty quickly at the rate it was going.

Installation was easy - one bolt, two coolant lines. Took a while to get the cooler in the proper spot on top of the filter housing. Now that I've done one, I bet I could do another in 15 minutes.

If you have an 2008 - 2010 Mazda 2.3, you'd better keep an eye out for leaks from the top of the filter housing. A tech at the Mazda dealer said they start out slow, but can let go quickly.

Not how I wanted to get acquainted with my "new" used car:



Under tray can hold a lot of oil, masking how much the car is leaking:




You can see the blown out portion of the oil cooler gasket at about the 10 o'clock position. New cooler has been completely redesigned.

[NYPorsche]

Hmmmm... thanks for the heads up.

Was this with the cartridge oil filter, and, if so - do you know if it is specific to the cartridge filter design?

I've got an '09 -3 and a '10 -5 - both have the spin on oil filter redesign. I'm hoping that the switch to the spin on filter took care of this.


Beyond this - I do love both vehicles - especially the 5. A mini van in which I did more than 30 mpg round trip to Cleveland this weekend.

However - the failure of a $0.07 seal causing the necessary replacement of a $400 part - very poor design.

[LeeH]

Mine's original with the cartridge type filter. The oil cooler looks like a little black can mounted to the top of the oil filter housing. There are two coolant lines coming out on the driver's side (14-700 in the diagram). The gasket is on the bottom of the cooler (my cooler is upside down in the pic).

I would assume that the spin on conversion would result in the original oil cooler mounted on top of the new oil filter housing.