Someone12132

Hello everyone,
Recently, my Z has started having this weird rattle/clunk noise at startup. After doing some research, many people have had the same issue, suggesting that it's possibly the slack timing chain tensioner that causes the timing chain to hit the timing cover until the tensioner receives oil.

Despite this, many people have said that they have lived with this problem indefinitely and that it is a common issue with the VQ35DE that Nissan has addressed as being "harmless". Meanwhile, others have said that it's something that must be replaced as quickly as possible as there is a risk of the timing chain snapping.

I have attached a video of how it sounds like on start-up.

I'm wondering what the urgency of this situation is? Should I buy a timing chain kit and replace the timing chain and all the tensioners as soon as possible, or is it just a small problem that can be ignored?

bre240z

Hard to really hear that video... at least on my PC. Rattle at start up is very common on these cars and most of the time its nothing too concerning. I personally woudlnt touch the timing chain unless the car is acting funky and has signs/symptoms of timing problems. Maybe just replacing the tensioner but If it was me I would just leave it alone. Replacing it is not a complicated job but if you dont have some wrenching on cars under your belt it can be a tricky job to do. Especially doing the timing chain.

I tend to have this rattle as well. It comes and goes. Usually happens during the cold weather but Ive also heard it during warm weather. What I usually do is crank the key a couple of times before starting the car. Just to kinda lube the motor before running it. Thats just what I do and im not sure if that helps but makes me feel better lol.

Someone12132

Yeah, sorry about the bad video.

It’s somewhat relieving to hear that it’s not necessary to replace the tensioners, guides, and chains and that it’s a problem that can be lived with.

I did cycle the ignition multiple times and did not hear it rattle when I started it up so I guess that’s nice.

Anyways just in case, I found this video on YouTube which showcases the same exact sound coming from my Z’s engine. Any sort of advice would be helpful.

bre240z

Ive never gotten that knocking noise from my start ups so it maybe related to the rattle problem the DEs have or not. Hard to say.

Someone12132

I forgot to mention this in the previous post, but it only gets this loud for 1-2 seconds when I haven’t started the car in a week and it’s parked on an incline. My oil levels are topped off so it definitely isn’t low on oil or anything for oil to not be pressurizing the tensioner(s).

For the most part, if I drive the car everyday during the week, the startup sound is only as loud as it is in the video I posted below:


For now, I’ll cycle the key multiple times to pressurize the tensioner before I start the vehicle to prevent timing chain from rattling on a cold start. I’ll order the primary chain tensioner first and see if that fixes it. Do let me know if I should possibly check anything else that could be causing this problem.

icer5160

iTrader: (4)

Note: The primary chain tensioner appears to be spring loaded, ratchet style. While the secondary CAM chain tensioners are hydraulic. If this symptom is related to oil pressure during cold start, then most likely the secondary tensioners are worn out and would need to be replaced or your chains have worn enough to create excessive slack, which requires more time for the tensioners to "pump up" and remove the slack. Or possibly a combination of both.

Either way, in order to properly address the problem, you would need to dig deep into the timing set. At that point you may as well do a full timing chain (tensioners, guides, chains, etc.) & water pump service. I would caution against leaving things as they are. If the wear on the chains or tensioners is bad enough, you risk jumping timing or snapping a chain which will grenade the entire engine ($$$). To be sure, a timing chain job on these engines, especially from a reputable shop in SF Bay Area, is not a cheap prospect, but it's a hell of a lot cheaper than paying a shop to replace the entire engine.

How many miles are on your Z? A full timing chain service is recommended around 150k mi to keep the engine running tip-top. But this is really based on how well the engine has been serviced and treated. If the car had extended oil change service intervals and was driven hard, then most likely the chain will wear considerably more vs. an engine getting oil changes done every 3k mi.

If you decide to get a timing chain service done, stick with OEM parts from a reputable supplier! Don't rely on Amazon or Ebay specials! If the shop you choose handles the parts purchasing, stress that you want OEM and that you want to see receipts!

Since you're located in Fremont, I would recommend reaching out to Rob @ Z Car Garage for an estimate. But I know Rob is always booked these days and typically doesn't like working on 350Zs anymore because so many of them show up as absolute hack jobs that would cost more to fix than they're worth. There might be some other tuner shops in the Bay with Nissan VQ experience, but I've never used them. Tagging @MicVelo to see if he knows of some other local shops you can trust.

Well that's my 2c.
Good Luck!
-Icer

MicVelo

Sorry, only shop I've used in last 15-20 years is ZCG. Used to be a couple of Z specialist around that I knew of and used decades ago but long gone (from the area at least). Only other shop I hear mentioned - but have no experience with so no rec - is Dando's in Fremont. I know that name from waaaaay back but do not know if they do Z33/VQ work.

icer5160

iTrader: (4)

Hey Mic,

Thanks for the quick reply.

Don's (in Campbell) was the only other Nissan & Z specialist I knew about besides ZCG. Sadly, Don retired back in 2019-2020. I heard there was a good performance shop in Fremont or Milpitas with Z experience (friends with Z32s used them), that was years ago though, not sure if they're still in business.
Cheers!
-Icer

MicVelo

I had Don do some S30 stuff for me that I was too lazy to do. He and I would talk shop - particularly about his antique "truck", a gennie - and I was bummed when he closed down. There was a bit more to it than just retirement. You know the old "greedy landlord" thing...

I think the shop you're probably thinking of in Fremont/Milpitas area is Dando's. They did a lot of S30 work back in the day but have since gone a little more mainstream (general all around repairs). They get really good reviews so I'm guessing they still do pretty good work.

Someone12132

Sorry for the late reply, but my Z has done only around 99,000 miles. The oil has pretty much always been topped off.

I posted a (hopefully) proper video of how the rattle sounds like outside after a cold start. One of my friends told me that they've seen a lot of Z's do this and that it's a common rattle with these VQ35DE engines that affect nothing. However, I would like to get everyone's opinion about this sound just in case it's actually something worst.

I'm thinking about taking a look at Z Garage and seeing how much they might quote.

icer5160

iTrader: (4)

I couldn't detect a rattle noise in your latest video, it sounded normal/healthy to me. So perhaps you can safely ignore it. Topping off oil and changing oil are two different things, it's good that you're keeping it topped off, but a full fluid change should be done frequently on these engines (Anything beyond 5k mi is pushing it IMO, especially if you got an oil burner and don't top it off). I'm paranoid with my Z, so I change oil every 3500-4k mi using Penn Ultra Plat 5W-30. I'll be switching to 5W-40 at my next service interval for better long term protection. My Z has just under 60k mi on the chassis and maybe 25 or 30k mi on a warranty replaced long-block from Nissan (due to oil consumption on Revups). Current rate of oil consumption is about 1/2 - 3/4 qt between changes which is considered normal/healthy for a Revup after 3500-4000mi.

Cheers!
-Icer

Someone12132

Sorry for the bump, but this is still relevant to my loud noise on startup. I always change my oil between 3k-3.5k miles, and barely burn oil (about 1/4 qt of oil burned between oil changes). However, pretty recently, I heard this loud clunk noise on startup. This is the second time I've heard this since my first year of owning my Z and daily driving my Z. My car was on an incline, and the temperature has recently dropped drastically within the past two days. The car also hasn't been started within the past 3 days. I caught the noise on my dashcam. I hope this is not the dreaded timing chain tensioners/guides, but rather something else.

Here's the video:

icer5160

iTrader: (4)

Was your AC in the "on" position when you started the car?

Did the noise happen right when you released the clutch pedal?

I've noticed I get a little chain noise whenever I shutoff the engine with the clutch released. By holding the clutch pedal in when I shut the engine off, I don't get that noise. Perhaps related to your issue?

I really hope you don't have a secondary tensioner guide that's worn through (plastic gone/broken, metal on metal grindage), apparently this can happen on the newer VQ37VHRs. Usually though, when that happens, you would get Cam/Crank error codes and the noise would be constant. Your symptom cleans up immediately, so this makes me think it's the tensioners pumping up in those 1st crucial seconds of starting the engine. You can hold down the gas and clutch pedal while cranking. This activates "clear flood" mode, so the engine won't start, but you will be able to prime the oil system after letting it crank for 8-10 seconds. Once primed, simply release the gas pedal and start normally. Try doing that after letting the Z sit for a few days and see if the noise/symptom is still present.
Cheers!
-Icer

Someone12132

This noise happened when I released the clutch. The weird thing is that it only does it when the car is at an incline and I cold start it. Even then, it’s very occasional (like once every 6 months). AC was in the off position when I started the car. Essentially it’s very rare, and it does it on random cold starts too.

In fact, I started it today morning and that loud clunk noise didn’t happen. I released the clutch like how I normally do after starting the car and still no noise. Is there a way to inspect the timing chain tensioners without prying apart the whole timing cover?

icer5160

iTrader: (4)

I’m not sure about the secondary tensioners, would need to check FSM. The main tensioner has a maintenance cover, one of the black covers, I think the one on the passenger side of the timing case. The drivers side is for the water pump.
-Icer