OT - Decision Process: Replace Timing Belt Now or Wait?

[DerbyDad03]

This question is about the decision process involved with replacing the timing belt in a vehicle "now" or "later".

Let's not confuse the issue with cost or voiding warranties, etc. Let's assume there is no warranty to deal with and that the cash is readily available, both now and later.

Here's the situation a friend and I were discussing the other day:

The manual - and therefore the dealer - says the timing belt on his vehicle should be replaced at 90K, which is right where he's at.

He called around to various repair shops for a price and multiple places told him "I've never seen a timing belt go on that vehicle before 110K. The dealers just want their money early. There's no need to replace it at 90K." He was even able to "verify" that opinion on the web.

OK, so let's say that you are planning to keep the vehicle for the foreseeable future, probably well beyond 110K. That means that you will need to replace the timing belt, probably in about a year, to be safe.

So here's what I was thinking:

There's a pretty slim chance that you'll keep the vehicle for the full life of the second timing belt. That would put you in the 220K range. Even if you replaced it at 90K and it really will last 110K, that's still pushing 200K.

Why would you wait until next year and not replace it at 90K? Even at the dealer's "accelerated" schedule, you're good until 180K, by which time you'll probably have gotten rid of the car, so why not be *extra* cautious and replace it now?

Thoughts?

[JoeSpareBedroom]

No, it's not "pushing 200K", unless you came from one of those families where math was considered an elitist subject.

Because you want to post messages on usenet, saying you "proved" that timing belts can last more than 90K.

Because you enjoy having your vehicle stop running when you least expect it, perhaps far from home where you have a mechanic you've trusted for years.

You also imagine that you can predict when the water pump will go bad.

Tell your friend to stop being a moron for a day and get the belt & water pump replaced.

[N8N]

Need to know what kind of car to answer that question. If it is a non- interference engine like my dad's old Pinto, the only consequence of it breaking is that you will have to walk home. If this is an interference engine like a newer VW 1.8T, the consequences of the belt breaking are much more severe, as in "which is cheaper, a new engine or a new car."

nate

[jamesgangnc]

Depends on the valve design. On some vehicles it is possible to have valve / piston interference if the valves are left open while the piston completes it's cycle. On other engines it is not possible for the valve and piston to colide no matter what their positions.

As you can imagine if your engine falls in the first category you can have a whole lot of extra damage if the timing belt breaks. On a 100k

• mileage engine it could be toast as the rest of the engine condition might not justify that sort of repair.

[SteveB]

FWIW, TY, I stand corrected. I made a statement that it would be no big deal if it stripped a timing belt, not being aware of the valve interface issue. When I worked on cars as a youth, you could set the points with a matchbook cover, and I could have the heads off a 283 Chevy V8 in less than an hour. Things have changed.

Steve

Visit my site at

All errors, brain farts, misspelled words intentional because this computer is set to Spelchek French, and I can't get it to do any different.

[Tony Hwang]

Hi, It is a matter of peace of mind particularly if the engine valve is interfering type. I am still driving '98 Honda CRV. No oil burning/leak, no rattles, perfect 3ven compression on all cylinders, Would I replace a car like this? No. I am on the way for 3rd belt.

[Ed Pawlowski]

First, determine if it is an interference engine. Go the the Gates Belt web site and you can look it up. They also give the recommended change intervals.

If it is interference, change it now or you can trash the engine. If it is no, you may be tempted to go a bit longer. Age is a factor also as rubber does deteriorate with age.

The manual does build in a safety factor. The key is knowing just how much. The cost of replacing now is $X.XX. The cost of waiting and having a faileure is $XXX + cost of a tow+cost of a motel if out of town+cost of other potential inconvenience.

If you are contemplating selling the car, a recently changed belt adds a bit to the resale value and buyer confidence for the new guy.

FWIW,. many manufacturere state 60,000 change times.

[Frank]

I replaced mine well before its time because I needed a new water pump and since belt was off the only extra cost was price of a new belt. I'm no mechanic but believe on some vehicles, a broken belt can be disastrous but on others it is not. If yours is one that could have a problem if the belt breaks, I'd probably do it now.

[clare]

You don't say what kind of car / which engine. Many are SHOT if you wait for the belt to fail. It's your nickel, but I'd rather replace it sooner than replace the engine.

[DerbyDad03]

ide quoted text -

While I am of the "do it at 90K" opinion, no one has addressed the fact that more than one independent repair shop - one of which I recommended because they've treated me right in the past - said to wait.

Why would they give up a job - and risk their reputation - when they have every "right" to just point at the manual and say "replace it at

90K"? Why push off a job now that they might not get a year from now?

[JoeSpareBedroom]

While I am of the "do it at 90K" opinion, no one has addressed the fact that more than one independent repair shop - one of which I recommended because they've treated me right in the past - said to wait.

Why would they give up a job - and risk their reputation - when they have every "right" to just point at the manual and say "replace it at

90K"? Why push off a job now that they might not get a year from now?

=================

Because they'll say anything to get rid of a customer who wastes their time with pointless attempts to predict the future. People like that cost them money.

[George]

How lucky is your friend? Thats what it really comes down to since the so called interference design is very commonly used. That means the pistons can contact the valves if the engine goes out of basic time. At that point unless it is a valuable car you sign the line on the title that says "dispose as salvage" and leave it on the dash.

[jamesgangnc]

There has been a tendency towards a non-interference design in later years. Older engines often had an interference design to maximize compression. With a chain driven cam it didn't matter much. Overhead cams lead to belts replacing chains since it was chore to enclose a chain between the top of the head and the crankshaft. But a lot of the early ones did still have interference valves. High compression mostly went away with low octane gas so it is a lot simpler to have a non-interference design now.

[trader4]

It's a good question why they would say that. If a mechanic told me not to replace a timing belt that the manufacturer says to replace at

90K because the mechanic has not seen one fail before 110K, I'd get a new mechanic. The guy is an obvious idiot. To me, knowing that you've seen them fail at 110K, 90K sounds like the appropriate place to change it.

Or how lucky do you feel today? As others have pointed out, it also makes a big difference if the engine design is interference free or not. If it is, then failure just means a tow, which by itself could be bad enough, depending on when it happens and the resulting consequences and costs. Also, since in this case apparently the car will be kept for significantly longer, but not long enough to require a second belt, the only apparent advantage in delaying is if something else were to happen to the car, eg totalled in a wreck or other repair that could be done at same time, that would impact on this decision.

[JoeSpareBedroom]

It's a good question why they would say that. If a mechanic told me not to replace a timing belt that the manufacturer says to replace at

90K because the mechanic has not seen one fail before 110K, I'd get a new mechanic. The guy is an obvious idiot. To me, knowing that you've seen them fail at 110K, 90K sounds like the appropriate place to change it.

Or how lucky do you feel today? As others have pointed out, it also makes a big difference if the engine design is interference free or not. If it is, then failure just means a tow, which by itself could be bad enough, depending on when it happens and the resulting consequences and costs. Also, since in this case apparently the car will be kept for significantly longer, but not long enough to require a second belt, the only apparent advantage in delaying is if something else were to happen to the car, eg totalled in a wreck or other repair that could be done at same time, that would impact on this decision. ================

"failure just means a tow"? Maybe.

Imagine suddenly NOT having engine power to maneuver around some sort of hazard. That could be fun.

[Larry Fishel]

Um... Possibly because they would rather have the bigger job of rebuilding your engine when it fails?...

IMO, even if they are correct that they've never seen one fail before

110K, that would make 90K about the right time to change it...IF it's an interference engine.

If it's not, then there's relatively little danger in waiting and a significant chance that if you spend the money now, the car will suffer some other catastrophic failure (that won't be wirth fixing) before the belt would have failed, making it a waste.

You still haven't said what kind of car. Aside from the interference issue, what car makes a big difference in how big of a project it is to change the belt. They might be thinking that will have some other reason to tear the engine apart soon and you might as well do the belt then...

Just a few (contradictory) thoughts...

[JoeSpareBedroom]

Um... Possibly because they would rather have the bigger job of rebuilding your engine when it fails?...

IMO, even if they are correct that they've never seen one fail before

110K, that would make 90K about the right time to change it...IF it's an interference engine.

If it's not, then there's relatively little danger in waiting and a significant chance that if you spend the money now, the car will suffer some other catastrophic failure (that won't be wirth fixing) before the belt would have failed, making it a waste.

You still haven't said what kind of car. Aside from the interference issue, what car makes a big difference in how big of a project it is to change the belt. They might be thinking that will have some other reason to tear the engine apart soon and you might as well do the belt then...

Just a few (contradictory) thoughts...

==================

You must live where it never snows for real. Either that or you have a strange definition of "fun", like breaking down when plows are passing by every 20 minutes to bury the road shoulders in snow.

[DerbyDad03]

Imagine if you had the slightest clue how the conversation went.

It was my friend who told the mechanic that the timing belt was on the dealer's 90K replacement list and he asked for quote to replace it.

It was the mechanic who replied that 90K was too early. The tranny fluid change made sense, replacing the spark plugs was probably a good idea, valve adjustments if there was any chatter, but changing the timing belt was not needed.

It other words it was the mechanic(s) who made the "pointless attempt to predict the future".

[Larry Fishel]

Actually, I believe it's snowed here twice in recorded history, but you make a good point... :)

[JoeSpareBedroom]

Imagine if you had the slightest clue how the conversation went.

It was my friend who told the mechanic that the timing belt was on the dealer's 90K replacement list and he asked for quote to replace it.

It was the mechanic who replied that 90K was too early. The tranny fluid change made sense, replacing the spark plugs was probably a good idea, valve adjustments if there was any chatter, but changing the timing belt was not needed.

It other words it was the mechanic(s) who made the "pointless attempt to predict the future". ============

I know. You should read slower.