QX56 Oil Cooler leak problems

[ryanfarrow84]

Hi forum readers!
I got a 2005 qx56 brought to me by a friend complaining about a leak in the front part of his engine..... pretty vague right?

I got underneath that behemoth and removed the splash/skid plate....
I noticed all the oil coming from where the oil filter area is. My initial thoughts was some young buck at the local fast stop oil change place didn't check to see if the old gasket from the old filter was still attached to the oil cooler where it screws into and had a double gasket problem....easy fix right?
Wrong!!!

After removing the oil cooler from the block I found a minor but big flaw in Nissans design of the o-ring for this part. it doesn't quite fit the diameter of the oil cooler flange that it goes in. This means old banana hands at said fast lube shop torques and untorques the filter on the oil cooler and messes up the seating of the o-ring over time.

Ok now for the research part.
I call around to Nissan and infinti shops and dealers....they all say I need to replace the entire oil cooler because they don't sell just the o-ring for that part separately.....quote? 450$ for just part and another 200$ in labor. NO THANKS!!! I did some research and found that the o-ring for the oil cooler on the 2004 Nissan pathfinder is slightly larger (ie. fits perfect into armada and QX56) so I track it down and price is $5.37....hmmm way better than 450$.

Ok the fix:
Anyone who has enough mechanical knowledge to do a small tune up can do this and save 200$ in labor. First remove the two coolant lines from either side of the oil cooler (try to clamp them before remove so as not to get a gallon of coolant coming out. and definitely avoid splashing on serp belt)
Second remove oil filter. Third use deep well socket to remove oil cooler connecting stud. (Part that oil filter screws into). Remove oil cooler completely and thoroughly clean all parts. Take out old orange o-ring and replace with new black o-ring. put back together in reverse order.

Notes:
When removing oil cooler if a small steel ball falls out that is part of your oil pressure valve system and need to buy a new one and install. Ball will only fall out if its bad in the first place.
After replacing oil cooler o-ring some people encounter their oil pressure saying its high even at idle. This means you need to replace the oil pressure sensor which is located right above oil cooler on side of engine. Usually caused by bad oil pressure valve stated above.
Nissan o-ring part number is 21304-ja11a
This job only took me 20 min after I had all the parts and knowledge
(which took me about 3 hours to get lol)

I hope this helps anyone who encounters this problem
Good luck and Happy ----yet safe----wrenching

 

[Silverback]

Thanks for the heads up and detailed information.

 

[roughyear]

Two Thumps Up Ryan!!

 

[motsbro]

Coming in her e a bit late . . 12 years late . . but here's a thought on the leaking oil cooler gasket. I replaced mine as advised by ryanfarrow84 above. pretty easy fix. But as I think about it my problem started after an oil change I did. I recalled now, the old filter was a bitch getting off. Its likely that getting the oil filter off may have loosened the retaining bolt/tube for the Oil Cooler itself allowign the leak to a occur. May help just to check it torque for hte retianin bolt, which from all accounts in 36 foot pounds. My gasket looked fine btw albeit a bit thinning than the replacment.

Also, YOu do nbot need to remove the coolant lines if you're not replaceing the housing. Just leave them and save your self the antifreeze shower . . . The lines are flexible enough to allow the Oil Housing to rotate to gain access to the gasket for replacement.