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Discussion Starter · #1 ·
I've noticed some oil on the driveway for a little while with my wife's 2007 FX35. The car now has 164,000 miles on it.

The last time that I changed the oil, I thought that the leak was coming from the oil cooler housing. I've read that there is an "O" ring in there that can go bad.

We recently had the car in to the dealer because we got a 2nd recall on the passenger air bag. Apparently the 1st replacement air bag could have a problem and rip as it's deployed. Anyway, the local dealer finally got the parts in after waiting for them since November 2021!!!! we have not decided if this was a supply chain issue, laziness, or stupidity. We had to call the dealer 3 times from November to ask "do you have the parts yet for this recall?"

Anyway, upon getting the air bag replaced, we were given a list of repair suggestions. One was that we should replace the two fan belts. The other was that we have a leaking oil pan gasket. I told them that we would get back to them because I was sure that it was the O ring in the oil cooler/filter housing. The service writer said "No, it's definitely your oil pan that's leaking.

The belts don't need to be replaced - at least not for another couple years. They don't show any signs of cracks, splits, fraying, etc. They are not squealing. The oil leak is a different story. I'd like to stop the leak.

Since the oil cooler housing O ring is not that expensive, I'm thinking that I will tackle that first and see if I'm right or the dealership is right.

As I understand, the factory didn't use a gasket. They just used thick layer of RTV Silicone sealant. Getting that apart is apparently tedious so that you don't bent the oil pan.

Does anyone have any experience with oil leaks in these Nissan/Infiniti 3.5L V6 engines to know if it would be more likely to be the oil pan versus the O ring - given the age of the car and the 164,000 miles?

The Fel-Pro oil cooler O ring is less than $6.00.
The Fel-Pro oil pan gasket is less than $20.

Any recommendations?
 

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Discussion Starter · #2 ·
I guess that it's a slow weekend in early August. OK. It appears from a You Tube video for the O ring remove and replace on a FX35 that I don't need to totally drain the oil first. Is this correct?

Thanks.
 

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Hi Funsize. Sorry, I don't have any personal experience with the oil cooler o-ring change but I seem to recall that you don't need to drain first. However, doing this repair while you are doing an oil change, and have drained the oil, seems like a good idea to me.
 

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Discussion Starter · #5 ·
Well, here's a new one for me even living in the Northeastern Rust Belt all my life.

The oil pan on this 2007 FX35 rusted on the front passenger side corner and a hole formed. I've never known an oil pan to rust through before. I was wiping and wiping to see where the oil was coming from and the oil pan kept showing oil in that spot. As I wiped harder, a piece of rust broke off and oil started to really seep out. I now have to wait for a replacement oil pan to arrive. I ordered a Dorman replacement with a lifetime warranty from Advance Auto at about 9 AM today. The price was $89.99 before tax.

I cleaned the mating surface on the engine with a single edge razor blade knife and some emory paper. Then I replaced the oil cooler "O" ring with Fel-Pro pat number 72493. It was only $5.49 before tax. I had to use my 22 mm deep well socket because the "regular" length socket was a little too short to grab the nut to remove the oil cooler. There's just enough room to work without disconnecting any of the lines going to the oil cooler.

I bought a Fel-Pro oil pan gasket instead of trying to use just silicone RTV like the factory. The oil pan gasket was $13.49 before tax. It's a shame that I had to remove the oil pan, that seal was dry as a bone after 15 years and 164,000 miles.

Oh well. You come up against all sorts of things when maintaining a 15 year old vehicle.
 

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Discussion Starter · #6 ·
Update - The Fell-Pro gasket was WRONG!! It was too big. I was able to return it. The length was good but it was about 1 inch too wide! I bought a new tube of Permatex Ultra Black RTV. The factory service manual says to put down a bead that is 4.5 to 5.5 mm wide into the groove on the new oil pan and around the bolt holes. I hope that my bead is adequate because I measured the width of the groove and it was about 5 mm from edge to edge. I filled it all the way around. According to the Permatex package, I now need to wait 1 hour from the initial hand tightening before I can torque the 10 bolts to 78 in-lbs ( I think that was 8.8 N-m for anyone working in metric). The RTV should be cured in about 24 hours and I will start adding oil to the crank case.

So, the moral of the story is that either the wrong gasket was put into the package or Fel-Pro has no idea how big the oil pan is on a 2007 FX35 AWD model. I can list the part number for this incorrect gasket but that may confuse someone and then they would call me all sorts of nasty names.

Now I have to hope that the bead of RTV that put down was correct
 
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