The EX35 started out with a fairly straight forward drivetrain. Over the years Infiniti has added power and gears to the transmission.

My question is; will the two motors used have equal reliability? Both rebuildable? How about the 5 vs 7 speed automatic? Same reliability? Both rebuildable?

Asking these questions because I want to keep my EX long term but also wonder if I should upgrade to a newer model?

Interested in knowing what those that understand our cars mechanics think? Would love getting 250,000 miles out of a car.

Sorry if I can't answer your question directly.

The 3.5 and 3.7 motors, and the 5 and 7 speeds were used in quite a number of models, including:
G sedan/coupe/Q40
FX/QX70
M/Q70
350Z/370Z
I believe the transmissions have also been used in Nissan's truck and SUV line as well.

I haven't looked extensively how the engines and transmissions have held up over time across all the different models, but at the same time I haven't seen anything alarming about them either that would make me question their reliability. As far as the EX35, there have been a few threads that have popped up about engine issues. At least for the earlier models, the most common issues I've seen had occured on the throttle bodies and the timing cover gasket.

For the transmissions, the only big issue I've seen was actually due to radiator failure. What would happen was that the lines between the coolant and ATF would corrode through and mix the fluids. This resulted in a "pink milkshake" in the transmission, necessitating a rebuild or replacement. This was much more common in the Pathfinder, Frontier, and Xterra models built prior to 2010, but I don't recall seeing this happen on their Infiniti models which likely use different radiators.

I know that the transmissions are defninitely rebuildable, and that the engines should be as well. However, unless a major failure occurs early enough in the vehicle's life, personally I think I would skip the rebuild and upgrade to a newer car. Rebuilds tend to be quite expensive with the amount of labor involved, and for me it would probably make more sense to put those costs into a newer vehicle. My situation warrants reliable transportation, and while I wouldn't have to worry about a newly rebuilt major powertrain system, the rest of the car still is still older and carrries the wear and tear along with it. I'm not sure what your situation dictates, but getting an engine/tranmission rebuilt may be a more sensible solution for you.

My EX35 now has 137K. It has had it's share of issues, but I think 200K is acheivable without requiring an engine/transmission rebuild. I'm not sure how well other components will fare however by that time. Even if I reach that mileage without any issues, I'll probably look to upgrade to something newer around that time and keep the older car around for a while. 250K is probably achievable as well, but I would guess that the likelihood of problems only goes up as the car passes that milestone and it would really push my risk tolerance for a daily driven car.

Thanks for the reply. The only major issue my EX has had was the radiator. They blamed the failure on the thermostat? Wish I had paid closer attention to this forum so I would have known of the issue.

Think I agree with you. Once I reach 150,000 miles or so, I will start looking for a replacement. Really like the car.

Nissan really messed up the valve cover gasket on the 3.5. The valve cover gasket will leak oil into your spark plug wells and it is very difficult and costly to replace.

Beyond that, they are pretty bulletproof.

mrzuzzo wrote: ↑

Thu Aug 24, 2017 10:20 am

Nissan really messed up the valve cover gasket on the 3.5. The valve cover gasket will leak oil into your spark plug wells and it is very difficult and costly to replace.

Beyond that, they are pretty bulletproof.

The plastic valve covers have been poorly designed since the inception of the G35. Just need to keep on eye on it (smelling oil) and try to get it covered under warranty. It's not cheap to change both sides.

Bocatrip wrote: ↑

Thu Aug 24, 2017 11:08 am

mrzuzzo wrote: ↑

Thu Aug 24, 2017 10:20 am

Nissan really messed up the valve cover gasket on the 3.5. The valve cover gasket will leak oil into your spark plug wells and it is very difficult and costly to replace.

Beyond that, they are pretty bulletproof.

The plastic valve covers have been poorly designed since the inception of the G35. Just need to keep on eye on it (smelling oil) and try to get it covered under warranty. It's not cheap to change both sides.

Yep, I messed up. I only noticed the leak after warranty expired.

Even if you get them replaced under warranty, they'll leak again eventually.

In this respect, Nissan failed with the design of this motor.

mrzuzzo wrote: ↑

Thu Aug 24, 2017 2:39 pm

Bocatrip wrote: ↑

Thu Aug 24, 2017 11:08 am

The plastic valve covers have been poorly designed since the inception of the G35. Just need to keep on eye on it (smelling oil) and try to get it covered under warranty. It's not cheap to change both sides.

Yep, I messed up. I only noticed the leak after warranty expired.

Even if you get them replaced under warranty, they'll leak again eventually.

In this respect, Nissan failed with the design of this motor.

Generally, it won't start leaking that quickly. Yes it's a poor design, but you can go quite some time before the leaking becomes severe. Even if it drips into the spark plug valleys, it won't cause the engine to misfire but does smell as it burns off the engine and manifold. Still a great engine and since the replacement will most likely be a 4 cylinder for 2018, it's leaps ahead with power and proven reliability.

This is true.

My EX has 130K miles. Not a single issue besides the mentioned slow leak into the spark plug well, which at this point doesn't affect driveability at all.

My 08 has 74k km, so what, ~45k ish miles? I expect I should be good for quite some time lol.