When to replace Timing belt

[r2m]

r2m - I'm coming up on my 90k service and am having a difficult time deciding exactly how much to replace. I know there are other threads on the topic but I would love to hear what you recommend based on the number of Timing Belt jobs you've done on the LCs and the fact that you've got your wife's at 238k so if there are lessons to be learned you probably can speak to them.

To be more specific - the laundry list is roughly:
Timing Belt
Timing Belt Idlers
Timing Belt Tensioner
Serpentine Belt
Serpentine Belt Idler
Serpentine Belt Tensioner
Water Pump
Thermostat
Cam Seals
Crank Seal

Did you do idlers, tensioners, water pump, seals, thermostat at each TB change?

One school of thought is replace all those things while you're in there - it's cost effective (at least if you're paying for labor) and the items typically fail b/f the next time you do the TB anyway so replace 'em all with each TB job.

There seems to be another school of thought don't fix it if it ain't broke - i.e. that replacing those items can also lead to failure (either faulty install or defective part) so don't replace them until they fail/start to fail.

What's your school of thought, and what parts do you replace at each TB job?

I'm trying to think, I believe on the last belt, we replaced the water pump, because something broke on it whilst removing it.
I've never bothered with changing pullies. Never heard about pullies going bad. Have had (on other vehicles) alternators and air conditioning units and pullies go bad and tear up belts, not any idler pullies. All the other fan/auxillary belts are simple enough to change at anytime. Just use common sence on what the current condition of them is. I would replace them if they are even close to looking worn, just 'cause I'm in there. But if they all look really good, save the money. I would replace any and all hoses, especially the difficult ones to get to.

And while you're in there, if you have the time, you do your spark plugs and maybe wires. Just a thougt, since you're already dirty.

If you're doing the work youself and have the radiator and fan out, and a few extra bucks and time, look into an electric fan replacement! I believe there's at least on thread on electric fans on MUD. A wee more horses and better cooling, not that I've ever had a cooling problem. No joke.

 

[NMuzj100]

So which of the items would you choose not to replace?

I would inspect each one and only replace those that looked likely to need replacement in the next 50,000 miles or three years.

I figure gas is as likely to go to $5-7 a gallon in the next few years as a randomly selected part is to fail. Both would park my 100.

Some say replace every hose. There are about 16 under hood hoses. None have a pattern of failure. So replacing them all will save no effort and you are more likely to create a problem replacing them than to prevent one.

I had Slee do my belt late at 150k and replaced

- Water pump - probably unnecessary but I followed the board crowd on this one - OEM is about $85 from American Toyota but has a single waterpump failure been reported on the board yet ?- Not that I recall - some did have evidence of dried coolant at the weep hole.
- Tensioner - There are documented cases of this failing (not many)
- Serp belt - Inspection showed aftermarket belt was ready to go and I replaced with OEM.

 

[Living in the Past]

Do the timing belt have to come off to replace the water pump? I know the 87 Pathfinder I use to own it did. I made the mistake of by pass having the dealer replace it when I had the timing belt changed. Within a few months it failed and I ended up doing the job myself. That pump was part of the guard for the timing belt.

While changing the spark plugs isn't a bad idea is there any advantage in changing the 12 volt wires leading to the coils/spark plugs on the 4.7?

 

[ebod]

My LC is a 2004 and has a bit over 60k miles on it. My dealer is about to replace the water pump on warranty. Should I consider having them do the timing belt too? I know it's early, but since they're already going to be in there, maybe the labor savings are worth it.

Thanks.

 

[agaisin]

My LC is a 2004 and has a bit over 60k miles on it. My dealer is about to replace the water pump on warranty. Should I consider having them do the timing belt too? I know it's early, but since they're already going to be in there, maybe the labor savings are worth it.

Thanks.

Can you find out how much more it would cost and what they would suggest doing since it's so soon? In other words, probably no reason to do anything more than just the TB itself - if they convince you to do the whole shebang that early not sure I would trust them. But if they throw in the TB itself for basically cost of the part, why not?

 

[NMuzj100]

My LC is a 2004 and has a bit over 60k miles on it. My dealer is about to replace the water pump on warranty. Should I consider having them do the timing belt too? I know it's early, but since they're already going to be in there, maybe the labor savings are worth it.

Thanks.

Yes. Replace the TB belt for sure. They will already have to remove it.

 

[Mister Tom]

Mine wasn't done until 147k. It was the original belt. When I bought my truck I completely baselined it including that service. That's a lot of miles on an original belt. I don't recommend this, but given the miles on it, I'm surprised it lasted that long! Toyota makes good parts

My son replaced the engine on his 2000 LC, due to timing belt failure at 147K miles. Says no light ever came on. Not a good excuse and should have known better. He never owned a car the had a timing belt versus chain.

 

[trdcorolla]

My son replaced the engine on his 2000 LC, due to timing belt failure at 147K miles. Says no light ever came on. Not a good excuse and should have known better. He never owned a car the had a timing belt versus chain.

I thought the 98-05 100's were non interference engines? Here's a thread I remember about a bad timing belt job (not sure if the same problem you had but it rang a bell in my head)

Timing belt job just done. Blown engine or savable? This is interesting guys!

Happy 2020 all. Well, I spent last day of 2019, inspecting a 2005 LC w/~200K, that was towed to me. That had a Timing Belt installed a few days before coming to me Let me know your thoughts: Blown engine from interference or is there hope? Also what do you think happened? Skip story and go...

forum.ih8mud.com

 

[97 AZ LC]

I thought the 98-05 100's were non interference engines?

Just because a timing belt failure doesn't harm an engine doesn't mean that there won't be mechanics who tell customers that their engine is ruined and they need a new one, and customers who believe them.

 

[Mister Tom]

Just because a timing belt failure doesn't harm an engine doesn't mean that there won't be mechanics who tell customers that their engine is ruined and they need a new one, and customers who believe them.

Don't disagree. According to my son...banging from the engine and then it was frozen.

 

[fro20fow]

My son replaced the engine on his 2000 LC, due to timing belt failure at 147K miles. Says no light ever came on. Not a good excuse and should have known better. He never owned a car the had a timing belt versus chain.

Do you know if it was the original belt?

 

[Mister Tom]

Do you know if it was the original belt?

He bought the LC when it had 19K miles, so guessing it was still the original belt.

 

[2001LC]

My son replaced the engine on his 2000 LC, due to timing belt failure at 147K miles. Says no light ever came on. Not a good excuse and should have known better. He never owned a car the had a timing belt versus chain.

Non VVT 2UZ-fe 4.7L:
I'd like to get my hand on that old 2UZ-fe non VVT engine Or pictures of the damage in cylinder(s) heads.

We've many accounts in mud of non interference, when belt broke even under load. Like when passing on the HWY. In these cases, new belt installed and all good. But there are a few that have replaced the engine, after a break non VVT. But none I know of, offered proof engine interfered. Proof like picture of valve(s) and position tops with damage.

I've long wondered if with a loose 2uz-fe non VVT engine with a lot of carbon build up, may they interfere. That is; wrist pin, rod & crank bearings worn, valve springs weak and carbon on valves and pistons. Could we interfere IDK at higher RPM, IDK but certainly plausible.

In this case, intake cam had moved while engine started and ran numerous times. We believed intake cam sprocket had moved into various position on cam, on various starts. Engine was fine.

VVT 2UZ-fe 4.7L engine:
I've seen pictures in a Tundra forum of damage exhaust valves. I've also had a service manager at Toyota Dealerships, tell me: "We bought client engine, after tech miss timed belt on 4.7L VVT timing belt job. But here again did they assume. You'd think they actually checked, by simple scoping cylinders! There is also a post in mud, where a supposed service manager listed very specific exhaust valve and guide damage. The VVT engine pistons are different, so there may well be less clearance.

Timing belt service:
My feel has been; I don't worry to much about a break taking out the non VVT, if over 7 years or 90K.
I do worry on the VVT engine, if even just over on years (7).
But if a break accrues, I'd dig deep before replacing either.

 

[MountaineerLC]

So which of the items would you choose not to replace?

I would leave the cam and crank seals alone if they aren't leaking.