Hi,
First post. It's a long story, but like a fool, I did not take notice of the 60 months or 100k miles notice to change my timing belt. I only had the 100k figure in my mind. I have a 2000 4WD with 99.3k miles. My awesome truck dies on the way home last week. Oh me.

A few hours later, timing belt had not broken, but ripped out about 3 inches worth of teeth. This is an interference engine I learn, oh joy. So, I need to remove heads and inspect valves and pistons, more joy.

A few more 6-8 hours, this dang intake manifold is out. Man, what a nasty big job. Nissan puts things together well! I have a few more hours left to remove exhaust manifolds and heads.

Oh, reason for this post. I just wanted to see if anyone here has gone through this already and has any thoughts to share. In the day, I used to work for Datsun, so I'm an old guy, so I know cars well and am not afraid to take on a project like this, but it is being done in my "backyard" and I thought this section of the forum was appropriate.

Thanks, I appreciate any insights.

Aloha,

I think Carlton (Admin) has rebuilt his engine and he did a whole thread on it, but I haven't been able to find it. Good luck. obtw some of the guys from Xterra Club Hawaii might be heading your way, assuming you are on Maui.

I was not aware of any 60 months figure for the timing belt.

My vehicle is also a 2000 and currently has about 72,000 miles on it. Should I change the timing belt now? Or wait until 100,000 miles?

my xterra is 8 yrs old and has 127,xxx on it and the timing belt kit i bought is still stting in the box it showed up in.

mauitom - i would have thrown a new belt on it and given it a try before spending all the effort to pull the heads.... but since you're into it now might as well finish up.

kcnissan - replace it... it's a ticking time bomb. Check out the timing belt kit that xterraparts.com offers - it comes with a new water pump (the water pump is BEHIND the timing belt - so you always replace it whenever you do the belt since you're in there anyway) new accessory belts etc.

South Side Ninja - you're going to deserve it bigtime when your motor blows.... and it's gonna happen really really soon. I wouldn't drive that sucker another INCH until the belt is replaced. seriously.

if you have a 2000 Xterra I would suggest doing the belt.

You do NOT want that to fail on our engine. It is expensive if it does.

Xterraparts.com sells kits for the person who feels comfortable doing the work him or herself.

It is not that difficult of a job. It just requires a few special tools (good impact wrench to get the driveline pully off)

Here is the link for the lasy people

Timing Belt Kits

Do you know of any good how-tos? I've looked, and I sort of need a newbie-ish how-to.

Here's an excellent write-up by dezurtrat. You'll have to join the board to view the pictures, but it's free.
Timing Belt Change

thanks i appreciate that. i know if it happens i will deserve it.

there are tons of people that own an xterra and do not get on any on-line discussion boards, and i'm sure that the majority of them dont know anything about the timing belt being due at 105,000, and i am even more sure that there are a good majority out there that havent done the timing belt and have gone way past the interval it should be done at... so does that mean that since i know better, that it is more likely to go bad before anyone else's that doesnt get on XOC?

i think i remember someone even posted on here that they hit 196,xxx without changing it, and several more that have had it changed and it didnt have even the slightest appearance of wear. i get your point, but i dont think its nearly as "life and death" as some make it.

i'm sure you're already to say "i told you so" if and when my timing belt goes, but honestly, i dont post questions and problems about my xterra like it was going out of style like some, so if the timing belt did go out, unless you knew me personally, you would never know about it.

i am gonna change it as soon as i get a chance to devote an entire day to it. i dont wanna fuck anything up and i am sure as hell not paying Nissan to do it.

Thanks for the replies. I just got back from a week in San Diego and Phoenix.

I'll be pulling the heads this weekend. If I find anything interesting I'll post a picture or two.

Kaiser - Since this is an interference engine, there should be no way that some piston and/or valve damage was not done, so throwing the timing belt on would more than likely just mean pulling it off again.

Others - To those of you who have not replaced it after 100k or 60 months, you're risking the same stupid thin I did. That's one of the resons I posted here. This was a very stupid, avoidable thing to do, i.e. not replacing the flippin belt. I drove this car like a little girl and mine broke. And even doing the labor myself I'm in for some decent $$.

If I have sustained severe piston damage I'm going to look in to a new block/bottom end or tow it down to a dealer and see what little they will give me. Heads, timing belt are a straight forward repair but it must be built on a solid bottom end.

My Dodge truck buddy tells me I should just drop a 400hp V8 in the thing and be done with it.

SSN, I'm not trying to be an ass (well.... maybe a little) - I'm trying to scare you into doing it before you're oh-so-sorry.

A friend of mine has his break at 140k and now he's screwed... his truck is just sitting there useless waiting for a new motor or some serious rebuilding. If he'd spent an afternoon getting this done it would be fine.

The last belt I replaced we did in about 4 hours.. it's not that big a deal to do.

Managed to get the driver side head off today. My exhaust manifold bolts/nuts are giving me fits. I've soaked the crap out of them with penetrating oil, but two of the three bolts broke. Going to take some effort to drill and tap those bad boys out.

Weird thing is that it appears that my engine is a non-interference motor. There are reliefs cuts in the piston tops. I can see no visible evidence of piston/valve collisions.

As a poor man's test of the valve seats, you can stand the heads up sideways and pour fluid (I used a motor flush) in to the exhaust ports, flip it around, and do the same thing for the intake side and look for leakage in to the combustion chamber. More bad news, 2 of the 3 exhaust valves leak, 1 of three on the intake side. So, I need to get the heads to the machine shop.

Piston and cylinder walls look good.

I started on the passenger side head, same crap on the exhaust bolts and I sure can't see how I am going to get to the back exhaust manifold bolts - there is no room! Hopefully tomorrow I can figure it out.

Any one want a truck cheap? Make me an offer. Lots of great parts!

this is a good time to do a body lift if you have any interest... it makes getting to the exhaust manifolds SOOO much easier.

There has been a lot of argument over whether or not this is an interference engine - with the general consensus being yes - but I wouldn't be terribly surprised if it isn't after all...

So what do you think would cause the valve leaking you're seeing if not a piston collision? Poor machining/seating in the first place? Head warpage?

By the way, if you can snap some pictures of the heads, pistons etc while you have it all apart it would be really interesting to see them.

this is a good time to do a body lift if you have any interest... it makes getting to the exhaust manifolds SOOO much easier.

LOL. I'll bet it does. No interest here for a lift, I put my mod money in to my Vettes. That's why this is pissing me off, my TomTerra is mostly my daily ride.

There has been a lot of argument over whether or not this is an interference engine - with the general consensus being yes - but I wouldn't be terribly surprised if it isn't after all...

I don't understand why Nissan wouldn't release the correct answer to this - seems silly that they do not. All I know is MY engine has cutaways on the pistons. It's possible that the valves still could hit them, but 'normally' this is not the case. I would have to do some tests to be sure, but this seems moot since I am getting valve leakage. My guess is that Nissan uses different styles of pistons in the same engines and list it as interference to cover their butts.

So what do you think would cause the valve leaking you're seeing if not a piston collision? Poor machining/seating in the first place? Head warpage?

Good question and it's not a black and white issue. If you tore apart 100 engines, even new ones, some of them would leak in a similar manner. It's not a fail safe test but it gets you in the ballpark. At this juncture in my little project, I'd say that it has nothing to do with timing belt breaking, it's simply the normal wear and tear of 100k miles. An engine will run fine with some leakage, you lose a little compression. When the machine shop goes to regrind the valves and seats they will be able to see if the valve stems are bent at all. This will confirm that they were 'interfered' with.

By the way, if you can snap some pictures of the heads, pistons etc while you have it all apart it would be really interesting to see them.

LOL, great minds think alike! I took a few but my camera does not want to upload them at the moment. I'll try again later and post them.

Instead of posting pictures here, I just created a simple web page. You can view it here,

Timing Belt - Cylinder Head Removal - 2000 V6

..been watching all this with great interest as it's on my list of things to do this summer. Sure wished I lived down the street I'd be over to help just to get the practice with the Nissan motor. -Last two timing belts I did were both Dodge and it's been over 10 years...

awesome site Tom!

By the way, while you have it apart you might want to look into the knock sensor issue (all of these trucks throw knock sensor codes - they don't light up the SES light). OffroadX posted some great info on relocating it to a more accessible place using a Maxima sensor.

Also, don't forget to replace the water pump while you've got easy access to it!

Saturday Morning
Timing belt change is straight forward. Read through the Chilton book (or whatever) a few times or three and try and buy/rent/borrow the right crank wheel puller. I bought one from Napa, it was the wrong one, but I managed to get it to work after some fudging about. Compared to yanking the heads off, it's a piece of cake.

Kaiser
Thanks for the compliment on the site - no big deal really. Regarding the knock sensor. I am a firm believer in leaving a car as the original engineers saw fit. I can't worry about every part, nothing will ever get done. I am going to replace all of those nasty small water hoses that seem to be all over this engine and leave it at that. I wouldn't have replaced the water pump, mine is fine, but since it came with the kit from Nissan, I'll do it of course.

Update
I got the passenger side head off this morning, yippee! I had to take it off with the exhaust manifold and cat on it. I can't see any other way to do it frankly. Even off of the car, I had to grind off all three of the bolts to remove the cat. Cripes, the cats weight like 400 pounds each!

Any suggestions for aftermarket headers? We don't have smog tests, but I would not want them to throw error codes. Just curious. The rest of my exhaust system looks like crap too, but no leaks.

I am so happy to get those heads off! I was seriously ready to give up, now I feel like I can get this done in a reasonable amount of time and expense. I just got back from Sears where I bought a $50 screw-out kit so I can remove/replace all of the bolts that broke or I cut. I need to sit down and order all of the parts I need to put it back together - blah. Heads will go to the machine shop later next week. I'll take the time to clean the block and engine parts while I wait.

I added a few pictures to the site today. One of the right side head off as I removed it and the engine compartment with both heads off.

I'm blabbing here but .... I also have an oil leak. It's either the rear engine seal or the front transmission seal. In addition, I have a 5 speed and I am still on the original clutch. I'm going to wait on these repairs until she's up and running again. It would be a bit easier to remove the tranny now, but I've got enough to do! :p

The knock sensor code is no big deal anyway... I'm just ignoring mine.

The leak is the rear main seal... happens to all of us.

The only headers I know of are from SLR, HERE

The only thing I worry about with them is that, on my truck there is only 1 catalytic converter on each side - right at the manifold. On later trucks there are four - two per side - and the SLR headers get rid of the two right at the manifolds.... so if I put the headers on my truck I would have NO cats.

Those headers and exhaust system look really nice thanks for that link. It does mention that they are for off-road use only, which means they must be fun and loud. There is no way the truck would pass emissions checks with them.

Rear main seal leak huh. Guess I'll ignore mine for the time being. Again, thanks for the heads up.

Easy day of repairs for me. I installed the new water pump and thermostat that comes with the timing belt kit. Cleaned everything up nicely - good old wire wheel again. With the holiday, I'll have to wait until Tuesday to get a hold of the machine shop.

One question -
The timing belt kit comes with a replacement bolt. It's the one that the tensioner fits over. This seems odd to me, the bolt is a large diameter one and I can't imagine it messing up. My original one shows no obvious sign of wear. Is this replacement bolt a known issue?

Thanks for the replies.

oh yeah - the tensioner stud... I have no idea why that is a replacement item.... We haven't bothered to replace it on any of the ones I've been involved with.

6.9.07 [update]
The good times continue. ;-)
* Machine shop tells me ALL of the valves are bent and need to be replaced. So, assuming they're giving me the straight story ( I have not seen the old ones yet), despite me not seeing any damage or scratching, apparently I do have an interference engine. I have ordered all of the parts to rebuild the heads along with all of the gaskets and water hoses from courtesyparts.com. I'm having the heads pressure tested too for cracks.
* I've been cleaning and painting parts as I wait for the parts and machine shop. There is a paint from Napa called black bumper paint. If you want a well priced paint that seems to stick to dang near anything, use this paint - it really is amazing for metal and plastic. I also highly recommend Super Clean, a water based grease remover - again great product.
* I got to cleaning the exhaust manifolds today. Gee, great big surprise. Crack in the right side (passenger) manifold. Nissan should stand up an admit this design flaw.

Has anyone here just had this crack welded up? I don't know squat about welding, but it looks like a bead would seal up the crack. Comments anyone?

I may just order after market headers and cats and be done with it. Blah.

They're cast iron.... very difficult to weld properly

6.23.07 [Update]

Hey kids ... I thought I would bring you up to date on my project. I got my heads and cats back from the machine shop yesterday.
* pressure tested fine, he resurfaced them and replaced all of the valves. Nice and clean!
* Paid like $150 to have those dang cat studs removed, blah. The guy said they are VERY well made and crystalize when they are heated - whatever that means, lol.
* I ended up buying a new right side exhaust manifold. I was going to get headers, but decided I 'll spend the money on new clutch and rear seal when I get this b*tch to run.
* Up early, bolted my new exhaust manifold (which I painted black) along with the heat shields (yep, black too). I replaced all of the studs and nuts on them, totally worth the money. Easy as pie like working on a new car!
* block head surface all cleaned up, extra cleaning in the cylinders, tapped out all of block head bolt threads. This is a big deal, mine are a mess with carbon build-up and all it takes is a couple of bucks and time to do it right. Accurate torque readings will ensue. Cleaned all of the head bolts and soaked them in oil too, again, big deal, do it right!
* lay the new head gasket on and get the head all in place, lays in nicely with the exhaust manifold and cat all mounted up.
* The head bolt tightening sequence is in 4 stages. I get to stage 2, about 84 foot-pounds. One of the longer head bolts BREAKS on me! I had originally ordered new ones, but the parts guy said Nissan repair guidlelines don't say to replace them, so I cancelled them - bad move. Lucky me, now I get to buy them afterall and I need another new head gasket.

Ah the joys of "doing it yourself". Good thing is it is being repaired to MY standards - this would have cost me many thousands at a dealer or other repair shop.

* I'll post some pictures later on the web site ...