Failure points
12-07-2022, 02:31 AM
#1
New Member
Thread Starter
Failure points
What are the common failure points of DE’s from experience? I’ve only owned car a handful of months have it put away for winter just want to revise everything I can.
12-07-2022, 05:40 AM
#3
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MY350Z.COM
MY350Z.COM
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The Nissan VQs are beautifully engineered and built V6 engines. In comparison with other engines, they really don't have any "failure points" unless maintenance is neglected, or they are abused in driving. They are reliant on regular oil/filter changes and keeping the cooling system intact. Have you checked the antifreeze in your Z before putting it away?
12-07-2022, 07:04 AM
#4
New Member
Thread Starter
12-07-2022, 07:06 AM
#5
New Member
Thread Starter
The Nissan VQs are beautifully engineered and built V6 engines. In comparison with other engines, they really don't have any "failure points" unless maintenance is neglected, or they are abused in driving. They are reliant on regular oil/filter changes and keeping the cooling system intact. Have you checked the antifreeze in your Z before putting it away?
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MicVelo (12-07-2022)
12-07-2022, 01:38 PM
#7
To add a few other items of note...
The radiator plastic endcaps have a tendency to fail from age (seals leak or plastic cracks). I would replace the radiator, radiator cap, main coolant hoses (upper & lower rad hoses), thermostat, and accessory belts. It's possible some of this work has already been done, but without documented service history, it's better to be safe than sorry. I would also replace the plastic T fitting at the passenger firewall/battery box in the engine bay. This fitting is installed inline with the heater core inlet hoses and is used for bleeding the coolant system when servicing. The OEM unit is plastic and the bleeder screw is also plastic! I highly recommend replacing this with a billet aluminum unit. The upgraded versions are offered by Z1 and others. It would be stupid to loose an engine from such a trivial piece of plastic. Also check suspension bushings, I saw the rear diff bushings mentioned, but also keep an eye on front end ball joints, LCA inner bushings, and compression rod bushings among others. These are all prone to failure. Less frequently failed bushings would be stuff like sway bar bushings and endlinks, but this all depends on how the suspension is setup. Lowered cars stress bushings more, running with failed bushings can lead to other bushings failing prematurely. Also keep an eye on the rear wheel bearings, these seem to fail at a higher rate than the 370Zs. Z1 offers an axle upgrade kit with Z34 wheel bearings (larger more robust).
One other item of note are the 6MTs in the 03s. They used cheaper stamped steel clutch forks which also used a longer pivot ball. This stamped steel fork is prone to flexing with aftermarket clutches and the longer pivot ***** have been known to break from the torque (side load) applied (I can't remember the proper physics term). Lastly, the early 6MTs are known to have weaker synchros and potential issues with I think 5th and 3rd gears. There are OEM upgrade paths for all of these (cast iron clutch fork & chromoly pivot ball purchased together, and the CD009 6MT). Note: You can upgrade the fork & pivot ball without the need to upgrade the entire MT. If yours is shifting great, then I would just leave it be. The fork and pivot ball are best replaced while doing a new clutch/flywheel. Same for the clutch hydraulics.
Other items to be mindful of as you approach the 150k mi mark...
Coil Packs, Injectors, Spark Plugs, and timing chain/water pump services. Some of these can be skipped over, but if you want trouble free operation and plan to keep the car long term, it's something to think about getting done. These are fairly pricey items to replace/service, so planning ahead is a good idea. I've never personally had a coil pack or injector fail, but I have seen many posts about these failing on higher mileage Zs. The timing chain/water pump service is best practice (preventative) maintenance. Overtime the chains do wear, some faster than others depending on oil service intervals. It's still a good idea to replace it at 150k along with the water pump.
You get out of these cars what you put in. If you take good care of it, it will last well beyond 200k mi.
Good Luck!
-Icer
The radiator plastic endcaps have a tendency to fail from age (seals leak or plastic cracks). I would replace the radiator, radiator cap, main coolant hoses (upper & lower rad hoses), thermostat, and accessory belts. It's possible some of this work has already been done, but without documented service history, it's better to be safe than sorry. I would also replace the plastic T fitting at the passenger firewall/battery box in the engine bay. This fitting is installed inline with the heater core inlet hoses and is used for bleeding the coolant system when servicing. The OEM unit is plastic and the bleeder screw is also plastic! I highly recommend replacing this with a billet aluminum unit. The upgraded versions are offered by Z1 and others. It would be stupid to loose an engine from such a trivial piece of plastic. Also check suspension bushings, I saw the rear diff bushings mentioned, but also keep an eye on front end ball joints, LCA inner bushings, and compression rod bushings among others. These are all prone to failure. Less frequently failed bushings would be stuff like sway bar bushings and endlinks, but this all depends on how the suspension is setup. Lowered cars stress bushings more, running with failed bushings can lead to other bushings failing prematurely. Also keep an eye on the rear wheel bearings, these seem to fail at a higher rate than the 370Zs. Z1 offers an axle upgrade kit with Z34 wheel bearings (larger more robust).
One other item of note are the 6MTs in the 03s. They used cheaper stamped steel clutch forks which also used a longer pivot ball. This stamped steel fork is prone to flexing with aftermarket clutches and the longer pivot ***** have been known to break from the torque (side load) applied (I can't remember the proper physics term). Lastly, the early 6MTs are known to have weaker synchros and potential issues with I think 5th and 3rd gears. There are OEM upgrade paths for all of these (cast iron clutch fork & chromoly pivot ball purchased together, and the CD009 6MT). Note: You can upgrade the fork & pivot ball without the need to upgrade the entire MT. If yours is shifting great, then I would just leave it be. The fork and pivot ball are best replaced while doing a new clutch/flywheel. Same for the clutch hydraulics.
Other items to be mindful of as you approach the 150k mi mark...
Coil Packs, Injectors, Spark Plugs, and timing chain/water pump services. Some of these can be skipped over, but if you want trouble free operation and plan to keep the car long term, it's something to think about getting done. These are fairly pricey items to replace/service, so planning ahead is a good idea. I've never personally had a coil pack or injector fail, but I have seen many posts about these failing on higher mileage Zs. The timing chain/water pump service is best practice (preventative) maintenance. Overtime the chains do wear, some faster than others depending on oil service intervals. It's still a good idea to replace it at 150k along with the water pump.
You get out of these cars what you put in. If you take good care of it, it will last well beyond 200k mi.
Good Luck!
-Icer
Last edited by icer5160; 12-07-2022 at 01:42 PM.
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12-10-2022, 10:03 AM
#9
New Member
Thread Starter
To add a few other items of note...
The radiator plastic endcaps have a tendency to fail from age (seals leak or plastic cracks). I would replace the radiator, radiator cap, main coolant hoses (upper & lower rad hoses), thermostat, and accessory belts. It's possible some of this work has already been done, but without documented service history, it's better to be safe than sorry. I would also replace the plastic T fitting at the passenger firewall/battery box in the engine bay. This fitting is installed inline with the heater core inlet hoses and is used for bleeding the coolant system when servicing. The OEM unit is plastic and the bleeder screw is also plastic! I highly recommend replacing this with a billet aluminum unit. The upgraded versions are offered by Z1 and others. It would be stupid to loose an engine from such a trivial piece of plastic. Also check suspension bushings, I saw the rear diff bushings mentioned, but also keep an eye on front end ball joints, LCA inner bushings, and compression rod bushings among others. These are all prone to failure. Less frequently failed bushings would be stuff like sway bar bushings and endlinks, but this all depends on how the suspension is setup. Lowered cars stress bushings more, running with failed bushings can lead to other bushings failing prematurely. Also keep an eye on the rear wheel bearings, these seem to fail at a higher rate than the 370Zs. Z1 offers an axle upgrade kit with Z34 wheel bearings (larger more robust).
One other item of note are the 6MTs in the 03s. They used cheaper stamped steel clutch forks which also used a longer pivot ball. This stamped steel fork is prone to flexing with aftermarket clutches and the longer pivot ***** have been known to break from the torque (side load) applied (I can't remember the proper physics term). Lastly, the early 6MTs are known to have weaker synchros and potential issues with I think 5th and 3rd gears. There are OEM upgrade paths for all of these (cast iron clutch fork & chromoly pivot ball purchased together, and the CD009 6MT). Note: You can upgrade the fork & pivot ball without the need to upgrade the entire MT. If yours is shifting great, then I would just leave it be. The fork and pivot ball are best replaced while doing a new clutch/flywheel. Same for the clutch hydraulics.
Other items to be mindful of as you approach the 150k mi mark...
Coil Packs, Injectors, Spark Plugs, and timing chain/water pump services. Some of these can be skipped over, but if you want trouble free operation and plan to keep the car long term, it's something to think about getting done. These are fairly pricey items to replace/service, so planning ahead is a good idea. I've never personally had a coil pack or injector fail, but I have seen many posts about these failing on higher mileage Zs. The timing chain/water pump service is best practice (preventative) maintenance. Overtime the chains do wear, some faster than others depending on oil service intervals. It's still a good idea to replace it at 150k along with the water pump.
You get out of these cars what you put in. If you take good care of it, it will last well beyond 200k mi.
Good Luck!
-Icer
The radiator plastic endcaps have a tendency to fail from age (seals leak or plastic cracks). I would replace the radiator, radiator cap, main coolant hoses (upper & lower rad hoses), thermostat, and accessory belts. It's possible some of this work has already been done, but without documented service history, it's better to be safe than sorry. I would also replace the plastic T fitting at the passenger firewall/battery box in the engine bay. This fitting is installed inline with the heater core inlet hoses and is used for bleeding the coolant system when servicing. The OEM unit is plastic and the bleeder screw is also plastic! I highly recommend replacing this with a billet aluminum unit. The upgraded versions are offered by Z1 and others. It would be stupid to loose an engine from such a trivial piece of plastic. Also check suspension bushings, I saw the rear diff bushings mentioned, but also keep an eye on front end ball joints, LCA inner bushings, and compression rod bushings among others. These are all prone to failure. Less frequently failed bushings would be stuff like sway bar bushings and endlinks, but this all depends on how the suspension is setup. Lowered cars stress bushings more, running with failed bushings can lead to other bushings failing prematurely. Also keep an eye on the rear wheel bearings, these seem to fail at a higher rate than the 370Zs. Z1 offers an axle upgrade kit with Z34 wheel bearings (larger more robust).
One other item of note are the 6MTs in the 03s. They used cheaper stamped steel clutch forks which also used a longer pivot ball. This stamped steel fork is prone to flexing with aftermarket clutches and the longer pivot ***** have been known to break from the torque (side load) applied (I can't remember the proper physics term). Lastly, the early 6MTs are known to have weaker synchros and potential issues with I think 5th and 3rd gears. There are OEM upgrade paths for all of these (cast iron clutch fork & chromoly pivot ball purchased together, and the CD009 6MT). Note: You can upgrade the fork & pivot ball without the need to upgrade the entire MT. If yours is shifting great, then I would just leave it be. The fork and pivot ball are best replaced while doing a new clutch/flywheel. Same for the clutch hydraulics.
Other items to be mindful of as you approach the 150k mi mark...
Coil Packs, Injectors, Spark Plugs, and timing chain/water pump services. Some of these can be skipped over, but if you want trouble free operation and plan to keep the car long term, it's something to think about getting done. These are fairly pricey items to replace/service, so planning ahead is a good idea. I've never personally had a coil pack or injector fail, but I have seen many posts about these failing on higher mileage Zs. The timing chain/water pump service is best practice (preventative) maintenance. Overtime the chains do wear, some faster than others depending on oil service intervals. It's still a good idea to replace it at 150k along with the water pump.
You get out of these cars what you put in. If you take good care of it, it will last well beyond 200k mi.
Good Luck!
-Icer
I appreciate the feedback.
the ignition coil stories are real i had a random misfire code a few weeks after i bought the car and i read the same thing from multiple people saying between 80-90k miles they tend to need replaced so i bought OEM from hitachi along with denso iridium plugs and it solved the problem.
Also i looked in to upgrading the clutch fork after reading what you wrote. i will probably go ahead and do that considering i need to replace the throw out bearing at some point soon before spring anyways. I noticed a little bit of rattle the other day when i started it up and it goes away with the clutch in.
the car is in good shape, stock with only 83k miles i just dont think previous owners cared for it too much and i waited a very long time to buy one i really just want to get this thing mechanically correct and reliable.
12-12-2022, 03:11 PM
#10
You're welcome! Here's the LINK. Looks like Z1 updated the design. Anodized black now, the one I picked up a year or so ago is raw machined alu. I went with the brass plug version since O-rings can fail (I prefer liquid thread sealer instead), but my OEM unit (o-ring design) never failed me after 106kmi, so you're safe either way. I highly recommend you get new OEM clamps if you go with this upgrade. They are a PITA to work with in the engine bay. New OEM clamps come pre-set (locked open) for easy slip on and install.
If you go deep to replace the throw-out bearing, I recommend the zspeedperformance ez street quiet clutch kit. I just installed one on my 06. This clutch has more than enough clamping force (can handle 400ft/lbs tq) for an NA setup, but it engages very smooth and it's virtually silent (pedal out) compared to my old factory clutch. If you daily the Z, it's an excellent option. I went with the 18.4lb single mass flywheel (still much lighter vs. OEM dual mass fw), and the gearbox chatter from torsional vibration is minimal to non-existant, I'm very happy with it!
Good luck with the Z!
-Icer
If you go deep to replace the throw-out bearing, I recommend the zspeedperformance ez street quiet clutch kit. I just installed one on my 06. This clutch has more than enough clamping force (can handle 400ft/lbs tq) for an NA setup, but it engages very smooth and it's virtually silent (pedal out) compared to my old factory clutch. If you daily the Z, it's an excellent option. I went with the 18.4lb single mass flywheel (still much lighter vs. OEM dual mass fw), and the gearbox chatter from torsional vibration is minimal to non-existant, I'm very happy with it!
Good luck with the Z!
-Icer
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SlowZ333 (12-17-2022)
12-14-2022, 10:25 PM
#11
350Z-holic
iTrader: (13)
I agree with what DK Mura has mentioned but things that have failed (usually my own fault) as far as the engine goes (take all these with a grain of salt, these fail when pushed past OEM power levels, and/or were upgraded in ensuing models).
Lots of spun bearings and I believe oil delivery through the crank to cylinder 3 and 4 is a bit long and I think they are slightly under-oiled
The OEM crank girdle / main cap assembly is pretty weak - look at the HR and VHR for the improvements
The original DE oil pump isnt great for exteme use - the RevUp pump is better, and a few companies make top tier pumps.
The DE has pretty weak rods (all things considered)
On the bright side -
The DE has one of the best transmissions on the market (even for today’s standards) and many swap engine kits have bell-housing mods to use the CD009.
The intake manifold is one of the best between the DE, RevUp, HR, and VHR - the DE despite not having variable exhaust cam timing, being heavy, made of aluminum (heat soak), a single throttle body, a 135degree U-turn in the neck, providing less flow to the front two cylinders, too much flow to cylinder’s 4 and 6 makes the most torque out of all the DE / RevUp / HR … and is only 2ft-lbs less (I think) than the VHR.
The DE has the most tuning options available out of the bunch
The DE has more upgrades/mods available
Arguable the DE has the most support out of all three
Lots of spun bearings and I believe oil delivery through the crank to cylinder 3 and 4 is a bit long and I think they are slightly under-oiled
The OEM crank girdle / main cap assembly is pretty weak - look at the HR and VHR for the improvements
The original DE oil pump isnt great for exteme use - the RevUp pump is better, and a few companies make top tier pumps.
The DE has pretty weak rods (all things considered)
On the bright side -
The DE has one of the best transmissions on the market (even for today’s standards) and many swap engine kits have bell-housing mods to use the CD009.
The intake manifold is one of the best between the DE, RevUp, HR, and VHR - the DE despite not having variable exhaust cam timing, being heavy, made of aluminum (heat soak), a single throttle body, a 135degree U-turn in the neck, providing less flow to the front two cylinders, too much flow to cylinder’s 4 and 6 makes the most torque out of all the DE / RevUp / HR … and is only 2ft-lbs less (I think) than the VHR.
The DE has the most tuning options available out of the bunch
The DE has more upgrades/mods available
Arguable the DE has the most support out of all three
12-14-2022, 11:45 PM
#12
Hey Beall,
I know you're focusing on the 2003-2005 VQ35DE, but the Revup-DE offered in 05 Anniversary & 06 6MTs has improved forged steel rods and slightly different pistons (hard to find the details on exactly what was improved with the internals). It also saw the addition of variable exhaust cam timing and improved oil pump. The factory air filter box on the Revup also included a velocity stack that was not on the non-revup models. I completely agree that the DE in general has amazing aftermarket support, which is one of the reasons I love my Revup-DE. It's an oddball for sure, but so far I haven't had any troubles getting Revup specific parts/components. I have a spare Revup Longblock that I plan in future to be rebuilt with improved internals and cams for an FI application. No idea when this will happen (if ever), every time I put cash away for car stuff, some other life event takes priority!
Anyway, I had to chime in about the Revup since I felt like it wasn't getting any love
Cheers!
-Icer
I know you're focusing on the 2003-2005 VQ35DE, but the Revup-DE offered in 05 Anniversary & 06 6MTs has improved forged steel rods and slightly different pistons (hard to find the details on exactly what was improved with the internals). It also saw the addition of variable exhaust cam timing and improved oil pump. The factory air filter box on the Revup also included a velocity stack that was not on the non-revup models. I completely agree that the DE in general has amazing aftermarket support, which is one of the reasons I love my Revup-DE. It's an oddball for sure, but so far I haven't had any troubles getting Revup specific parts/components. I have a spare Revup Longblock that I plan in future to be rebuilt with improved internals and cams for an FI application. No idea when this will happen (if ever), every time I put cash away for car stuff, some other life event takes priority!
Anyway, I had to chime in about the Revup since I felt like it wasn't getting any love
Cheers!
-Icer
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bealljk (12-15-2022)
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