Time Vs. Mileage on Timing Belt...

[SuperDave456]

So I drive a '04 Nissan Xterra 2 days a week and it has 60,000 miles on it. Regular oil dino changes every 3,000 miles from new-2008, and Synthetic every 5,000 miles since then. It has a 3.5 quart sump for its 6 cyl engine and thats as far as I am comforable going on an OCI, it does not have the turbo.

I have been thinking about this for awhile and cannot turn up anything definitive.

What is the determining factor on the timing belt, Time or Distance?
In the maintenance book it is 5 years or 92,000 miles, or something close to it. (I don't have the book in front of me.)

What are your thoughts?

 

[Hokiefyd]

I'd go with what the book says. I was going to say that most of the time, I don't hear time quoted...just mileage. 105,000 miles is the common interval. But if they quote a time-or-mileage number, I wouldn't have any information that would cause me to go against that.

 

[shrooms]

Go to 92K.

 

[tinmanSC]

IIRC, the Xterra has the 3.3L VG33E, right? If so, that is an interference engine. If you break your timing belt, it's gonna bend your valves and you're gonna have a bad day.

Best to stay with the manufacturer's recommended interval, IMHO. For time or mileage, whichever comes first.

 

[Ursae_Majoris]

I had the same dilemma recently. My Isuzu is 8 years old, but has only 60K miles. OM recommends TB changed at 75K, many owners wait till 100+K. It is a non-interference engine, so it is not a biggie.

I had a dealer take a look at it recently. They said TB looked fine. I think I'll wait another 2 years and replace it then (along with a tensioner and WP). It should have about 70K miles and 12 years by then.

Serpentine belt takes more beating than a TB, being exposed to the elements. My first one was replaced 4 years ago at 30K and it needs to be replaced again in a 6 months or so (starting to develop cracks)

 

[SuperDave456]

About a year ago I had the belts replaced, has a series of them instead of a serpantine.
And about 6 months ago I got tired of hunting for a coolant leak I could smell. It was under the hood, but I couldent find it.
Turns out that it was the radiator leaking from its seams. So it has a new one on there.

I have a great mechanic, I will have them take a look at it here soon.
And yes, I have done enough research to realize it is an interfearance engine. Broken Timing Belt = Very VERY bad day

 

[bigmike]

Non-interference... I'd be tempted to never change it. JMO, of course. That's what we did on the old '86 Nova. One day, cruising home, the engine quit. I think it had 120k miles on it or so. Towed to shop, new timing belt, drove home. No big deal.

Now an interference engine... that's another story!

 

[Quest]

while I understand that the longer you delay the timing belt servicing, the better in your position (just like many other car owners w/ t-belt), I would rigidly follow the factory servicing interval and abide by it unconditionally, for they actually calculated their T-belt servicing interval by careful engineering and materials used, with the standard distribution curve to support.

In my dad's 7th gen civic case: car was 10 yrs old (D17A1), factory recommended servicing was 150,000kms. I did it @ 148,000kms (3wks ago) with factory idler tensioner (genuine OE Honda Jpn parts) and Gates T-belt (factory OE Honda also uses Gates on this engine), OE Honda waterpump, etc.

With that in mind, this car is good for another 150,000kms or until it's scrapped.

Q.

p.s. D17A1 is of interference engine type.

 

[MrCritical]

Used to be a service advisor at a Honda-Buick-GMC-Jeep dealer in the early nineties.

Can't remember the t-belt recommended interval at the time-seems like it was kind of short, 60k maybe?

Had them towed in all the time at 65k or less.

 

[CBR.worm]

I have always wondered about this as well.

On my first tundra I didn't do the timing belt the first time until 140k miles. But I still had the OE serpentine belt on which was in good condition. logic said that the serpentine belt should wear out before the timing belt, but I went ahead and did it anyway. Down here in S. Florida there are no temperature extremes (hot and hotter).

I know you can't tell much by looking at timing belt unless it is at the point of failure, but it looked brand new.

At the time I was running 50k a year so it was less than three years from the in service date that i did the belt. i suspect i could have gone much farther. I was thinking though that as much time as i spent off road and/or pulling a heavy trailer full of tires to tracks every weekend it was still pretty severe service.

 

[donz26]

The Nissan VG33 timing belts are supposed to be replaced at 105k (I just looked at the FSM --there is no time specification). My '01 Frontier only has 79k. I know of cases where the belt has gone way beyond 100 k and cases where they failed before 100k.

Quick edit --VG33's are interference engines, belt breakage = $$$

 

[Spector]

Had one 8 years old with 25,000 on it, had it done but after removal informed it was still in excellent shape. A lot depends on whether you have interference engine or not. None interference you can take the risk

 

[ItsuMitsubishi]

I can't think of how time would affect a belt.

Engine rotations (and maybe temperature extremes) are really the only thing that can wear it out, and since that's hard to measure, mileage is the factor of choice to go by.

+1 on non-interference and taking the risk. I've personally seen them go for up to 220Kn (~137K Miles) KMs before breaking, and on a non-interference engine, the fix was quick and effortless.

 

[Gary Allan]

I didn't read all the responses. Quest's, as usual, has the most rational justification with concrete support for his disposition.

Quote:
I can't think of how time would affect a belt.


I think that anything that's idle for long bouts will somewhat age prematurely. I don't know if I can communicate this well for peer review here. Hmmm..take your alternator ...if it's on a 12 year old daily driver ..it probably looks like a dirty/dusty/grimed new alternator. Look at the same alternator in the junkyard, it's oxidized. Tires, over the same period of time, will be dry rotted compared to those in use. Now I may be mis-applying oxone/UV degradation to a component that's not typically exposed to sunlight, but I tend to observe different fatigue counts in the total lifespan. Somethings have so many heat cycles until they're fatigued. The duration of use may be high or low mileage (like a rad hose) based on the miles contained within the cycles. But I'm sure that there's also another fatigue component that doesn't usually enter into the life span of a hose. If not cycled at some unknown frequency, embrittlement will set in and then heat cycling degrades the component at an accelerated rate.

Now the t-belt isn't a heat cycled component, per se~, but the mileage spec is probably based on given norms of frequency of use.




Yes, this was mostly wasted bandwidth, but with 3 cups of coffee ...and this is, after all, BITOG ..

 

[mechtech2]

Old style timing belts with square teeth were generally recommended to be replaced at 60k maybe up to 80k.
The newer rounded teeth ones go 80K or more.

But mileage is MUCH more important then time.
Otherwise the new belt that you replace it with could be no good! It may have been sitting on the shelf for longer than the one that you are replacing!

 

[Tornado Red]

I think time is the crucial factor -- but hours of operation, not years since installation. Timing belts and their assorted tensioners and pulleys are experiencing wear whether at idle, or cruising at 20 mph in the city, or traveling at 75 mph on an interstate highway.

So IMO neither years nor miles adequately captures the amount of wear -- only the hours on the engine. Which the owner will have to estimate unless he has a hobbs meter installed...