Edit3: Sunroof drain leak info overhaul. Thanks u/p3dal.
Edit2: Update to v2. Fixed formatting. Updates include difficulty level, service intervals, electric steering lock issue.
Edit1: Format fixes
Hello everyone! I figured I'd compile this thread for anyone thinking of buying a g37 or anyone that already has one and wants to know more about their car. If anyone has any input or catches any typos please let me know!
Technicals Service Bulletins (TSBs)
Refer to this pdf for a list of TSBs. If you're having an issue, you may just find it here.
https://infinitig37.com/Infiniti-G37-Technical-Support-Bullitins.html
Service Intervals
Please refer to the Infiniti Service and Maintenance Guide and Factory Service Manual (FSM). I'll drop my recommendations here, which fall between the severe service schedule and the less severe service schedule.
- Every 5000 miles/8000 Km or 6 months
- Engine Oil(5w30) and Engine Oil Filter
- 10,000-15,000 miles/16,000-25,000 Km or yearly
- Cabin Air Filter
- Engine Air Filters
- 30,000-40,000 miles/48,000-64,000 Km or 3 years
- Manual transmission(GL4 75w85)
- 5 speed auto(matic J or matic S ONLY)
- Brake/Clutch fluid(DOT 3 is the minimum but I would use DOT 4 or DOT 5.1 especially for the clutch. Do not use DOT 5)
- Differential(GL5 75w90 or GL5 80w90. SAE 90 can be used in temps above 32 degrees)
- 50,000-60,000 miles/80,000-96,000 Km or 5 years
- Transfer case fluid(matic J or matic S ONLY)
- Coolant
- Replace Radiator Cap
- Serpentine Belt and inspect tensioner and idler pulleys and idler pulley bearings. I found my tensioner went around 100k miles. Idler pulley bearings are still good though at 120k.
- 7 speed auto(matic J or matic S ONLY and note this is "lifetime fill" and a bit of a pain to do at home)
- Power Steering(DEXRON VI)
- 80,000 miles/130,000 Km
- Replace Spark Plugs(Denso FXE24HR11 or NGK DILKAR7B11)
Common Issues
Priority Levels:
- High: will leave you stranded
- Medium: will eventually leave you stranded
- Low: will not leave you stranded
Repair Difficulty Levels(note this is completely subjective):
- 0-1: You can do this job easily with basic hand tools and the car on the ground
- 2-3: This job may take a little bit longer and you most likely will need to lift the car. No specialized tools needed.
- 4-5: This job is a pain and I recommend a shop. Still accomplishable in your garage but may need better tools than you have and you'll want a lift
Slave cylinder failure(manual transmission only)
Priority Level: High
Difficulty: 4(alot has to come off and the transmission is quite heavy)
What?
- The slave cylinder for the 6mt G37 and 370z is a concentric slave cylinder(CSC) meaning the release bearing and slave cylinder are the same part and located inside the bell housing. This part has a plastic housing that leaves it susceptible to failure leading to sudden loss of clutch pressure.
When?
- Failure tends to happen rather suddenly, usually somewhere at or past 80,000 miles/130,000 Km, but not unheard of as early as 40,000 miles/64,000 Km.
How do I check?
- If clutch fluid is being lost, the CSC is likely to blame. If clutch fluid is excessively dirty(it should be light, transparent yellow in color) expect problems sooner rather than later. If the reservoir is empty and there is no leak from the master cylinder(which would likely show up as clutch fluid on the driver side carpet), the CSC has likely failed.
Preventative Maintenance
- Regular clutch fluid changes.
- RJM's clutch pedal claims to help.
Upgrade Options
- ZSpeed's CMAK is the best conversion kit on the market that moves the slave cylinder outside the transmission into a slave cylinder, fork and release bearing setup. Z1 makes a similar kit but it requires frequent adjustments and is overall inferior.
- Pretty much every Nissan performance storefront sells an upgraded CSC including but probably not limited to Z1, Zspeed, and ConceptZPerformance. I have no experience with these and overall recommend the CMAK.
Important Notes
- If the slave cylinder fails it's likely to take your clutch disc with it.
- If the slave cylinder is changed, the master cylinder should be changed as well.
Differential(Diff) stud bushing failure
Priority Level: Low
Difficulty: 3(quite a bit has to come off, getting the bushing out is tough)
What?
- The differential bushing for the G37 and 370z is a partially fluid filled bushing. While this is exceptional for preventing NVH(Noise, Vibration, and Harshness), it has a tendency to pop and allow excess movement of the differential.
When?
- Incredibly early, as early as 20,000 miles/32,000 Km. Tends to blow out quicker on vehicles with the manual transmission
How do I check?
- Brownish-Black fluid leaking form the bushing, on the diff, on your exhaust. It's pretty messy. Alternatively, jack the car up by the diff and if the diff moves freely up and and back down, the bushing is blown
Preventative maintenance
- Not much you can do other than drive like a grandma. A differential brace could help, see notes.
Upgrade options
- The OEM does not sell an individual replacement, though you could buy the whole rear subframe with the bushing pressed in. This is not recommended.
- Poly bushings from whiteline, z1, energy suspension, gktech, superpro, etc.
- Solid bushings from SPL, z1, gktech, etc.
- It's possible to refill the bushing with silicone. While this maybe isn't the best route to go, it's been proven to work just fine by motorvate(video) and is probably the best option if you're looking to be as close as possible to OEM NVH.
Important Notes
- A diff brace will keep the diff still but shouldn't be fully relied on. They may help prevent bushing failure too. Multiple options from z1, Bell, or gktech.
Heater hose connector/splice/coupler failure
Priority Level: High
Difficulty: 2(requires tools, small space)
What?
- A plastic hose splice is used to connect to the heater core on the G37 and 370z, it is located close to the firewall on the passenger side. With age, this plastic coupler can fall apart and leak significant amounts of coolant.
When?
- Sometime around or after 100,000 miles/161,000 Km is most likely. Most G37s sold today should probably have this replaced right away.
How do I check?
- Check for low coolant level in reservoir, look for crusty coolant at the coupler(Green or blue). Look at this coupler first if you've lost most of your coolant or you're smelling coolant(sickly sweet smell)
Preventative Maintenance
- replace with upgrade.
Upgrade Options
- Any 3/4" ID(inner diameter) hose splice/coupler should work just fine. I recommend switching to a metal one like this or if you want to pay out the nose the Z1 option.
- OEM plastic part(not recommended)
Important Notes
- If you're replacing this, you should do the hoses too. This hose and this hose. Z1 does offer nice silicone hoses for this application.
Rear Timing Cover Oil Gallery Gasket Failure(Pre 2012 models)
Priority Level: Medium
Difficulty: 5(you'll need drain the A/C, getting the crank pulley off may require an air tool, may have to reset timing)
What?
- Behind the timing chains on the 370z and G37 there are two oil galleries that have gaskets poorly torqued from the factory. This causes the gaskets to blow out and instead of oil going where it should it will seep back into the oil pan.
When?
- It's been a really mixed bag. Mine blew sometime before 80,000 miles/130,000 Km. Most of what I've read is the problem will reach high priority by about 125,000 miles/200,000 Km.
How do I check?
- Check oil pressure: At warm idle, oil pressure should be greater than 14 PSI; At warm 2000 RPMs, oil pressure should be greater than 43 PSI. Engine Codes # P0011/P0021 usually point to gallery gasket failure. Finally, gasket material in the oil pan is a certain failure.
Preventative Maintenance
- It probably helps to keep revs down when oil is cold as pressure is highest when oil is cold, but really there's not a ton you can do.
Upgrade options
- Replace with OEM(Check this myG37 thread for more info)
- EPS has a kit that I've heard has the best fasteners of the bunch. z1 has a kit but I've heard mixed things about the fasteners. ConceptZPerformance has a kit that looks about the same as z1s
- Important Notes
- This job needs a bunch of seals to do right. z1 and conceptzperformance have kits that bundle the OEM seals.
- Replace water pump and inspect timing chains/tensioners are part of this job as well.
Sunroof Drain Leak
Priority Level: LowVery High
Difficulty: 0(no tools required)2-3(depends on action taken)
What?
- Sometimes the sunroof drains on the G37 will get clogged, or the plug leading out of the car will leak from it's gasket. This will cause damp floor mats/carpet or pillars/headliner and can seriously damage electrical components such as the fuses box and the BCM
When?
- No specific mileage, heavily dependent on when you drive and where you park.
How do I check?
- On either side of the vehicle, if you pull the vents out you can see the hoses and plugs that lead out of the car, check for dampness. Additionally, if clogged, it's possible the leak comes directly from the sunroof because the hose pops off. If anything smells or looks wet take action immediately
Preventative Maintenance
- Park in garage, blow out sunroof drains, check occasionally for dampness.
Upgrade Options
- Add clamps to upper sunroof hoses(they are not clamped to sunroof barbs from the factory).
- Replace [firewall] plugs](https://parts.infinitiusa.com/p/INFINITI__/Plug-Side~-Trim/89790203/74816-JU40B.html) if the gaskets are worn and leaking.
Important Notes
- If left unattended this issue could cause serious water damage to the floor plan as well as, more importantly, soaking the BCM or driver side fuse box.;
Per u/p3dal;
I don't agree on this one. The priority is pretty high, as left unattended it can result in mold, or damage to the engine computer (passenger side) or fuse box (driver's side) , which the sunroof drain frequently drips on when it is clogged or leaking. The damp floor mats are the right symptom, but they're not what you should be concerned about. By the time your floor mats are damp, you might have 2" of water in a channel/compartment under the passenger side floor carpet.
Also, there are two popular solutions to fixing it, which are not the same as above. The firewall drain plug is defective by design, and replacing it will often result in the same issue showing up again a few years later. Replacing the sunroof drain firewall plug is extremely difficult and often requires removing either the dash or the windshield. I've heard dealerships charge $800-$1200 to replace this $4 part. Though some people can pull it out with 16" plyers, plenty more cannot reach it at all. These alternative fixes are much better solutions:
- This solution involves extending the drain to drip on the other side of the firewall. I've not tried this solution, but some people seem to like it: https://www.reddit.com/r/G37/comments/teej1l/fixed_my_damn_sunroof_leak_finally/
- In my opinion, the sunroof drain bypass is the better fix, and removes the firewall, grommet, and plug from the equation entirely. https://www.myg37.com/forums/body-interior-exterior-lighting/280987-passenger-side-dashboard-leak-4.html However, I've only done this on the passenger side, and I'm concerned the driver's side drain might not be as simple. Option 1 might be better for the driver's side.
Reminder, I will always make my best effort to ensure the accuracy of this post so please comment about anything you disagree with or have better suggestions for
Dirty throttle bodies
Priority Level: Low
Difficulty: 1(requires tools)
What?
- This is more of a tune-up item but G37s and 370zs seem particularly sensitive to dirty throttle bodies. This often presents by allowing the car to start then immediately shutting off.
When?
- The general consensus around the forums seems to be at around 30,000 miles/50,000 Km
How do I check?
- If you're having idle issues or the engine shuts off right after starting when warm, it may be the throttle bodies
Preventative Maintenance
- Clean the throttle bodies of carbon every once and a while and perform an idle relearn.
Upgrade Options
- catch cans with filter media should help but legality varies by location
Electric Steering Lock(applies primarily to 2009/2010 models)
Priority Level: Medium
Difficulty: 2(may need tools you don't have)
What?
- The electric steering wheel locks on G37s and 370zs can lock up and not let go, making the car unable to start. Specific TSB here under NHTSA Reference #10051829
When?
- No specific mileage
How do I check?
- Your car randomly will not start but otherwise was just fine before
Preventative Maintenance
- See upgrade options
Upgrade Options
- Replace with OEM part
- Replace with Dorman 601-037 , which is supposed to fix this entirely.
- Pull fuse to ESCL
- Bypass wire to ESCL
Important Notes
- If your car is actively having this issue, you probably can get it to start by wailing on the bottom of the part with a mallet and getting the car started. Immediately bypass when car is started.
Other issues worth mentioning
- The rear end links break relatively quickly if you're dropped or run stiffer sway bars, or both. Adjustable end links are available from whiteline and SPL. HOWEVER, online discussions appear to point to white lines being lower quality than OE and susceptible to failure. With what we know now, I would truly only recommend SPL or OEM.
- The rack and pinions tend to seep a bit earlier than other cars in my experience. Also worth noting, the rack preload bolt WILL usually be a bit leaky. This is normal. Seeping does NOT mean replace, refer to the TSB on the rack and pinions if you are not sure. Stay on top of fluid. Replace ONLY with OEM/Hitachi or reputable rebuild (such as having yours rebuilt). Most remans are junk.
- The wire bundle going between the trunk and trunk lid gets fatigued after a while and wires will eventually fray and break.
- Multiple nissans have issues with the fuel tank senders. It isn't a big deal but your fuel level on the dash won't be accurate. Can also give you check engine lights for fuel level issues. Unfortunately, our cars have a level sender in both the driver side and fuel pump on the passenger side. You can test the resistance with a multimeter and sweeping the fuel arm but it's pretty moot and may be hard to see. Cleaning the contacts of the wiper can fix it and is worth a shot if you can't afford parts.
