Quick general question

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PattiM
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Quick general question

Postby PattiM » Sun Nov 14, 2021 3:52 pm

So, apparently the 2002 Pathie has a timing *chain* - so this is more robust than a timing belt, right? I mean, it should last longer than 145,000 miles - or is this year pathie in need of a preventative chain/tensioner replacement?

THANK YOU,
patricia


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palmerwmd
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Re: Quick general question

Postby palmerwmd » Sun Nov 14, 2021 7:09 pm

Patricia,

yes, your 2002 pathfinder's VQ35DE six-cylinder engine has a timing chain.

Generally timing chains are considered a superior solution to timing belts and are expected to last the life of the car. (whereas timing belts need changed at regular intervals at 700-1100 dollar cost each time)

Generally there is no fixed maintenance interval where timing chains need to be changed.
Both my Nissan SUVs have timing chains and are at 160,000 and 173,000 miles respectively, have never had their chains replaced and I am not even considering it, despite being otherwise almost obsessive with maintenance.

That was the short answer, however allow me to add some granularity to this response:
..it is still a mechanical item and every once in a while timing chain (or more likely their internal support gear like chain guides/tensioners) may need replacing.

Your vehicle has one of the most reliable engines made by any brand and barring unforseen events should last another 100,000 miles at least, if not longer, but it is still a mechanical device and it is not invincible to neglect/abuse/bad luck.

There are 3 possible (very rare) events that could break even the very best engines:
- Timing chain or belt breaking or jumping time
- A broken down catalytic converter "filling" getting ingested by the engines backpressure (so dont ignore that Check engine code about a bad catalytic converter!)
- Injectors stuck open and flooding the cylinders (so dont ignore a check engine light code about faulty injectors)

None of the above are common events on your engine but they do happen on rare occasions to any modern engine including the VQ35DE.
There might, and I emphasize might, be a statistically slightly higher incidence of timing chain tensioner on the VQ series engines but it is still quite rare and not common at all and generally announces itself via a weird noise first.

Coming back to the chains, if there is a symptom , like a weird whine or even rattle coming from the front of the engine I would get it looked at sooner rather than later, as it could be indicative of some trouble (ultimately if your chains break, or do jump time, it could quite likely cost you your engine)

Timing chain jobs are not cheap, generally more than a belt job so only consider them if actually necessary.
They, TC jobs that is, are unlike timing belts, not a preventative maintenance item but performed in response to an identified issue.

Since i cannot be certain what prompted your post, I have to ask was it a weird noise?
Or is someone telling you to change the timing chain at an interval like a belt?

Please do not let all those "what ifs" I listed above for completeness sake, scare you in any way:
In the absence of any symptoms such as weird noises or Check engine lights, nothing needs doing!

But if you think you hear something weird (whine or rattle) when in doubt have a Nissan tech listen to your engine to determine where it comes form ( could be a much cheaper item too)
Or you can post a clip to the board here ( take the video clip with volume close to the front of the engine with the hood open and rev it a little then post it on viemeo or youtube or bitchute or the like) and we will listen to it for you.

Cheers,

Fred :)

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smj999smj
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Re: Quick general question

Postby smj999smj » Sun Jan 23, 2022 9:07 am

There are actually three timing chains; one chain around each bank of camshafts and a primary chain that runs from the crank to the cams. The only ones that really had any issues with them in Pathfinders were on the 05-10 VQ40DE engines of the R51 series. With those, problems were caused by upper chain links that got stamped by worn tooling, which left sharp edges causing them to cut into the plastic upper tensioner "feet." As long as the oil was kept clean, chain failures in the R50s are practically unheard of.


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