salimshah

Based on hunch ... some one had a oil leak in the timing chain cover ... the chain gets lubed.

Old hands can comment on this more authoritatively .. typically the bottom of the main gear (on crank-shaft) sits immersed in oil... [I have only worked with timing belt]

Salim

TRDFantasy

Yes, the 3.5L uses a chain while the 3.3L uses a belt. The reason they went to a chain is better reliability and durability as well as less maintenance. Chains typically never need to be replaced, and even if they do they last a long time.

123go

First off Thanks, wasn't sure if belt/chain in 3.5 until this site...
Sorry' chains never need changed hardly isn't really true. They really don't go much longer than belts today and honestly I've seen many chains fail on Nissan/Infiniti & GM cars having under 100k even. I mean a lot!! Enough to get lawsuits flying if you look online.
Actually most old school V8 engines the big three made could fail at anytime after 85k. Most old single cam engines reached around 125k but it all depends on how hard the car/truck was driven/towed as their chains either stretch or sprockets teeth wear down/broke off allowing chains to slip off, but' myself I've had several chains break before 120k.
The belt earned a short life rep from the very start because they first recommended the minimum time line of the 60k for belt changes. Most then went to 80k (mid life) and remained for yrs but' later Honda finally stated 105k recommendations so many followed on. I remember the mid 70's Dodge Colts stated 60k on their Myitchybushy engines but' you'd be lucky to see it back then too.
But as belt materials progressed over the decades, today's belts hold their own quite well compared to chain life and why Harley Davidson has used them to propel even their heaviest bikes loaded down for decades now without issues. I've seen them put through pure hell and back without failing.
Now for cost, if one actually does the math and keeps a vehicle long enough the belts setups are much cheaper to replace over time even with shorter intervals due to not buying sprockets alone. My V8 Tundra timing belt was less than half the cost for parts with a single belt/etc. vs my wife's Infiniti (3) chains & sprockets etc.. added up to. I replaced all tensioner's after seeing my Toyota 4Runners hyd one had failed upon changing mine at 92k. I've used Full Syn & on time in everything since 2000, I think road salt or spraying under the truck to clean driving in local car washes as it rusted its stem up and seized so "Yes" they sure can fail before they claim and $45 is very very cheap insurance.
Our Infiniti made it to 120K before chains started rattling (light foot driver) but my truck gets changed at 100k give or take a few k? Still life then but water pumps can fail and make belts come off, very rare on Toy/Lex as toy routes pumps weep hole to miss pulleys/belt, I pull/haul/drive really hard like any other truck owner. Wife's old car a 1988 Maxima wagon got (2) belts at 100k each and it later reached 360k miles last I saw my friends son in it that bought it. Sons 1992 Saturn light foot too got 140k with chains. Friends Chevy Aveo went through two engines within 90k for belt failures, neither engine made it to 50k. Yup, that little poc...lol Lot of belts/chains fail too soon due to poor engine design imho design/materials always effects them better/worse sooner/later it will.
My old 2005 Tundra here is on its 3rd belt now, has over 350k miles still driven daily.
So' don't choose a vehicle your planning on keeping long term by the belt vs chain changes because you'll lose today and like salimshah posted its mainly "External Factors" that determines this with most engines, not what will last ya' I'll bet that it true.
Well' theirs those who just refuse to buy one for fear of driving belt engines after hearing that 60/80k age old bs line, Sorry, lol... It was true long ago yes, that's still effecting sales I bet so its surely sways car makers judgments and costing me so stop saying it..lol. Toy/Lexus stopped stating min interval periods like Honda did long ago so it helped change most our minds.

Longest running belt I personally pulled off a car was on a 2000 300m with 187k mi, belt looked brand new, hyd tensioner was seized at max position so bad my 335lb cousin put its tip on my stone house and gave it his all and it never even budged a ticks terd. My neighbor bought that 300m new but was never told to change it, how it was still on & running fine I'll never know. Longest I read about was a V8 LandCruiser over 250k mi. That was until googling it & hitting link below. Sorry long one but hope to help ease those minds who own either one of them. Especially Aveo, get r gone!!..lol
How far belts can go, sometimes?
Peace!

Felix

Belts vs chains......I'm either, or as I've had both.....mostly chains being on v/8's. Looking at the gen 2 rx's, I was open to either a 3mz or a 2gr powered rx.....The 40 hp+ & more grunt is a + on a 2gr powered rx. Yea it is a open deck block, but then so is all the gen 3 Hemi's as well as the 23 in the RS foci...The gr is a noiser mechanical motor, but is also has vvt on the exhaust side, better flowing heads......The 3mz is also a great motor as well, which is easier to work on & is quieter. Either or for me, but its great to have a little more grunt & a tad bit more efficiency. I looked at both so I was open to either....Main thing for me was condition, color & what options w/ being a 330 or 350 last.

CarComp

Timing belts last for ages.TONS of four cylinder engines used them for many many years, in cars no one EVER maintained. They just keep on going. Really, a 330 could easily be driven well over 150k miles, and possibly further with zero worry. My Chrysler Lebanon has a Mitsubishi 3.3L v6 with a timing belt. It is well past 300k miles. My Sebring has a 2.5L with close to 200k.

It really will be fine. Timing belt isn't just going to spontaneously snap in two. That is, if you drive like a sane person and don't bounce the rev limiter all the time.

Additionally, a timing chain might as well be considered "good for the life of the engine". It's not going to break / wear out / disintegrate. They just don't do that. I've seen double row timing chains with completely trashed / worn out tensioners on the GM quad4 engine , or the Jeep 4.7 V8 just slapping and banging around, and they just keep on going.

Felix

To add to that.....Have a look at a few 4.6 sohc Ford's & quite a few of the 5.4's when the tensioners go out......& you sure wouldn't want nothing to do w/ a Ford 3.5 in a fwd/awd vehicle as the w/p is internal & is driven by the t/c, no issue till the seal goes out. Gen 1 & 2 w/p's for the 3.5's use the same seal btw.....

CarComp

it should be obvious if your seal goes out. Next oil change will be milky. FWIW though, the chain will be fine even if that happens. Might not be good for your main bearings.

Felix

At least when it does go, it'll drip down a little trauff which the coolant will drip right near the alternator & on the ground vs the early 3.8's that needed head gaskets in fwd vehicles( Taurus,Sable, Continental's) vs rwd vehicles, same as the 35 where the w/p is external such as in the 150's.