MY350Z.COM - Nissan 350Z and 370Z Forum Discussion

Time for a new timing chain??

Rob189 — Sat, 25 Apr 2026 07:48:02 GMT

Hey guys.

I come seeking guidance. Long story short, my 2004 350z has been giving me some grief.

It all started when my CPS (crank pos sensor) died on me last year. I replaced the visually broken sensor with an aftermarket sensor and happily continued on. A month or 2 after then I experienced the same symptoms and assumed a dud CPS. Replaced it again, but that didn�t solve my problem.

I then suspected cam pos sensor. I took the car to a workshop to put in a new clutch and smf and asked them to fix the issues while they were there. They said that they ran some diagnostics and that my timing chain is stretched (I wouldn�t be surprised if that is the case as the car has 210k km on the clock). That job is too big for them and told me to seek help elsewhere (they gave recommendations). I can do that job myself, but don�t want to unless I have to.

AI then went and sought out a second opinion from a guy that specialises in Z�s but is on the other side of the country. He reckons its just non-OEM sensors causing all this nonsense. I replaced the CPS with an OEM sensor - car still sad. I�ve now ordered OEM cam sensors - they�re arriving next week.

In the meantime, I dug up my old 2-channel oscilloscope and ran some tests.

My symptoms are as follows: All sensors installed - car won�t start. Unplug CPS - car starts and will allow me to drive around a bit, but it will ultimately die on me.

When I ran the scopes, I got some interesting results. Some of the signals seem to be inverted, which is super weird - hopefully the new OEM sensors will fix that. (For info - the aftermarket sensors were Bremi�s). I also noticed that the timing was a bit out (I think).

My scopes were taking during crank as the car didn�t want to starts. Are there any experts here that can tell me if the chain is stretched or if I�ve jumped some teeth? I have also attached a scope that I found online of a healthy vq35de at idle.

Thanks,
Rob

Both cam sensors

Healthy VQ35DE

Oil Pressure Issue After Rebuild

FairmanZ — Mon, 20 Apr 2026 02:46:24 GMT

Just finished up a head gasket replacement on this reman motor ran less than 100 miles. Head lifted due to incompetence and poor assembly from the machine shop that sold the motor. replaced every o ring and gasket with oem, including gallery gaskets. I did the job in car, so I avoided removing the upper oil pan. After starting the car, it runs good and has oil pressure upto spec across rpm range. Once oil comes upto temp, however, oil pressure drops dangerously LOW. Verified with a mechanical gauge : 3-6 psi at warm idle.

Past 1k rpm, pressure resides within spec.

I am stumped. Changed oil weights to 10w-40 in hopes of it being related to bigger bearing clearances with the reman, no luck� oil light will still come on at warm idle.

Does the upper pan need to come out to diagnose further, since it�s the one part I didn�t install myself that could be causing this issue? Are oil pumps or the pick up tube known to go bad? Any chance it could be the O rings between the upper pan and block? Or should I start with looking over my work behind both timing covers?

Or Is it not even worth trying to diagnose, considering how poorly the motor was assembled. Should I just send it as is, maybe throw some lucas in it?

Tweeter - Necessary?

JCat — Sat, 18 Apr 2026 21:07:49 GMT

I installed new coax speakers in my doors.
.
Should I invest in tweeters to replace the stock ones ? Or mount some in the A pillars ?
.
or ?

Poly/solid bushings

Mattedg_man — Tue, 14 Apr 2026 01:40:30 GMT

For people that have replaced all or a significant amount of their rubber bushing with solid or poly, and specifically in the context of autox/track use, how large or a difference did this change make?

Is it worth the money and hassle involved? I only care about the performance. I don't street drive the car so ride quality is not a concern.

Thanks

AC Hose One-Touch Connector Failure

OneLapZ — Sun, 12 Apr 2026 22:37:52 GMT

2003 350Z. The One Touch connector at the condenser failed. AC stopped working and left a pool of oil on my garage floor. I tracked the issue to the one touch connector on the flexible high pressure line where it connects to the condenser. I replaced the o-rings and snapped it back in place. Gave it a good tug. It was certainly connected. Evacuated the system to -29 or so. Checked for leaks - none, vacuum was solid. Started charging the system and bang, one touch connectors coupler failed again.

My plan now is to replace the flexible hose and the coupler. I assume there is no way to fix the coupler. I�m guessing the spring seal thing has just gotten old.

Anyone else ever have this issue? Could there be something else that is causing the coupler to pop off? Is changing the flexible hose straight forward? My issue is that I have a Vortech supercharger, so I�m not certain on how to get to the compressor without removing the SC. Uggh. Any thoughts on those problem would be appreciated.

Alternator squeak?

llcrzz — Thu, 09 Apr 2026 02:53:12 GMT

hello, im having issues where I hope someone can help give some answers to. I recently changed my alternator as my oem was going bad, new alternator is bosch brand; however in the process of removal, coolant has spilled onto the belt and pulleys, after starting there was a loud squeak and I noticed the alternator was not charging (slipping) and once the squeaking stop then the alternator would charge again. as of right now ive changed the belt (gates) and replaced the whole belt tensioner assembly (z1) and it continues to squeak and slip. Is this happening to anyone else? is there any solution? I greatly appreciate any and all responses; thank you. (note: squeaking usually goes away after car warms up but continues to squeak after another cold startup.)

06 350z not pulling the coolant back after cooldown

Harp7 — Tue, 07 Apr 2026 22:41:11 GMT

Hey guys, I am new here. I hope I posted this in the right section.
I have a problem with the coolant system on my 06 350z.

Basically the car pushes a finger's width worth of coolant into the overflow bottle each drive but never pulls it back, so after like 4 - 5 drives (about 1h - 1:30h each) the rad is low, the heater goes cold, and the car starts to slowly overheat.

Thing is I am not losing the coolant. I can just pour it back, bleed the system, and be on my way again.

Obviously I am scared the head gasket is on its way out, but I did multiple Co2 Block test and they all came back negative. I also did a pressure test of the coolant system, and it held the PSI for 10 hours overnight. There is no smoke or rough running and no continuous bubbling when bleeding. The coolant hoses only get firm after about 15 mins of running.

I tried multiple radiator caps oem and aftermarket, all with the same result. I replaced a lot of the spring hose clamps around the radiator with proper screw clamps. I checked the radiator neck and overflow hose for imperfections, cracks, or leaks.

Honestly, I don't know anymore. Only thing I can think of is to throw a new radiator in her, but I'd like to get some second opinions. I really want to fix her, but I don't just want to throw money and time at it without even having a real lead on what it could be.

How Do You Effectively Use a Workshop Service Repair Manual?

pilegreatest — Tue, 07 Apr 2026 21:32:59 GMT

Hi everyone,

I'm looking for guidance on using a Workshop Service Repair Manual effectively. I recently purchased a manual for my vehicle but I'm unsure how to interpret torque specifications, diagnostic flowcharts, and wiring diagrams. How do experienced mechanics approach these manuals when troubleshooting complex issues?

Are there common mistakes beginners make when following procedures or disassembling components?

Do you rely strictly on the manual, or combine it with online resources and practical experience? Any tips for organizing notes, tracking repairs, and ensuring safety while working through manual instructions would be greatly appreciated.

Low oil pressure vq35de

Patrick10202 — Tue, 07 Apr 2026 09:34:48 GMT

Hi everyone, I have an oil pressure problem with my 2005 Nissan 350z VQ35DE and the motor that is currently in the car has driven around 150.000km and has 10w60 oil. I have driven it for the past year and a half with this oil without any problems but recently when I send it to a mechanic for a replacement of the rear main seal because it was leaking and also got a new clutch and flywheel installed.

But since i got it back there is a significant drop in oilpressure mostly noticable at idle. Then its barely above 0psi. Around 1k its 30psi and from 3k onward till like 5k it hangs around 60psi but the pressure bounces a bit. I added some photos of the psi at different rpm's.
The oil pressure sensor has already been replaced and also oil pressure has been confirmed with an external oil pressure tester.

First i thought about the gallery gaskets altho unlikely for a DE, so i bought a replacement set but when changing them the original ones didnt show any sign of leakage they sealed perfectly. I still replaced them but that didnt fix the problem.

Some other suggestions ive gotten where faulty oilpump or crankshaft bearings but havent had the time to check them out because when i take something apart might aswell replace it. But that would be a bit expensive unless i know almost for certain that it will help.
So if you have a suggestion what it could be please let me know!

Upper oil pan seal gasket change - how to

rudva — Sat, 04 Apr 2026 15:51:21 GMT

Since the upper oil pan seal is leaking, and to change cost at the shop is really expensive ($2,000 labor + $40 parts)

There is any guide or tutorial to do it by myself? I found a couple videos all of them show the horizontal engine holder, then remove the lower bridge but none shows where the chains to hold the engine should be, is not clear at all.

Do I need to remove the clutch flywheel? Or is because tjere another gasket there to change?

There any way to do it without removing the bridge?