What damage does not changing a timing belt do?

One of our cars is a VW on which I have changed the timing belt a few times. Contrary to what has been said by some, my used belts are not stretched and I can notice no difference in how the engine runs from before and after a belt change. The belt teeth show no visible wear after 60,000 miles. There is no visible way to determine if a belt is used a little or a lot. Used belts for me show a little scuffing on the back side; that is all.

If there is any way to know how long a belt has been used, it might be possible use a rubber hardness tester but the only one that I am familiar with is a Durometer A tester which may not be appropriate for a timing belt as the belt’s cross section is very thin. It is reasonable for me to believe that rubber timing belts harden with use due to exposure to heat over time and this could be used as an indicator of life remaining if a proper hardness tester was available. The condition of the reinforcing cords would be another matter; possibly even less easy to determine.

Rather than make timing belt condition a scientific endeavor requiring special equipment and precise measuring techniques, it is easier and less trouble prone to simply establish a time and mileage limit.

Don’t forget to install a new tensioner pulley and/or water pump with your new belt.

It is a unfourtunate situation when proof of timing belt replacement is missing. Some level of proof can be found in the presence of “work marks” but they are not good enough.

Timing belts don’t always fail by snapping. They can also shed teeth. I saw that happen on a buddy’s Pinto, well acutally a Mustang II but they were really restyled Pintos.
Fortunately, it did not cause a valve to piston collision and I helped him install a new belt, in the center of the highway median, and he was good to go.

The old timing belt was intact but there were enough teeth or cogs broken off to completely span the drive pulley and the belt just quit turning.

The Bottom Line On Timing Belts And Used Car Purchase . . .
. . . choose one . . .

[list] Have the owner produce documentation of a timely belt replacement for the specific car.[/list]
[list] Just plan on having the belt replaced when you buy it and get it home (allow $$). [/list]
[list] Take the word of a total stranger who may be selling to avoid belt replacement. [/list]
[list] Select a car that doesn’t have a timing belt, but rather a chain (not as much a concern).[/list]

Also, as has been pointed out, water pump and belt tensioner(s) would be good to see replaced with the belt, particularly at higher mileage. The reason is that a timing belt installation is necessary on most cars to renew these items and also, they can “take out” a timing belt if they fail from age/wear.

CSA

“Should I learn how to change the belt myself and do it?”

With all due respect, HoustonRice, based on your questions in various threads, I have come to the conclusion that you have no experience with automotive maintenance or repair. If I am correct, then you don’t want to begin your automotive self-training with something like a Honda timing belt replacement. If it had a non-interference engine, I would say to just go ahead, given the probability that incorrect installation could be rectified without any harm coming to the engine.

However, given the interference design of a Honda engine, the probability of you causing major engine damage by incorrect installation is very high, IMHO. When you finally buy a car, I suggest that you buy a good repair manual for the car, and that you begin your self-training with regular checking of fluids and changing of air filters. Then, you might graduate to replacing spark plugs. After you are more familiar with things automotive, then you might want to buy the special tools needed for replacing a Honda timing belt and you might want to tackle that job–slowly and carefully.

Trust me–the chance of you transforming that Honda engine into a steaming pile of scrap metal is very high if you or any other automotive neophyte decides that he is ready to change the timing belt as his first foray into repair. This is a job for someone who really knows his way around engines and who has a thorough understanding of how they work. This is not something where an automotive neophyte can afford to “cheap out” with a DIY repair job. Or, to put it other words, you can’t afford to save this much money.

If I have (in the words of the great philosopher, G.W. Bush) “misunderestimated” you and your automotive expertise, then I apologize for any incorrect assumptions.

Absolutely IMPOSSIBLE to tell.

A timing belt can look very normal and can snap a few seconds later.
In fact, that has been reported on this forum on a couple of occasions.

Unfortunately, it is beginning to look like HoustonRice is seeking rationalizations for buying a car with an overaged timing belt and not changing it. I hope that my interpretation is wrong.

I strongly suggest that he either NOT buy a car with an unverified timing belt change or that he resign himself to the necessity for having the job done by a qualified mechanic immediately after purchase.

Sometimes A Water Pump Leak Will Continuously Saturate & Lube The Belt And Over A Period Of Time, Coolant Will Soften The Teeth And Away We Go . . . Kaa . . Ching!

CSA

This was on a 1995 BMW 318Ti. The owner stated that the engine was started and it made a rattling noise for about 15 seconds and the engine stopped. Up until that time they stated there was no noise from the timing chain at all. Had there been, they would have had it replaced before the engine was trashed.

Tester

FWIW, two Toyota V6 pickups have been serviced here with noisy idle. The timing belts were past due and the belt slack had hammered the timing cogs’ key ways, destroying the crankshafts.

Sure they weren’t timing CHAINS???

I don’t know how a timing belt could destroy a crankshaft…Rubber/fiberglass is NOT that strong…Second…Belts will break before they stretch…Also belts are very quiet…even when loose.

Good post; you make a good case for trusting mileage and elapsed time to change the belt. Forget the physical appearance. Most rubber products (including condoms) have a “best before date”. Consumer Reports urges tire buyers to check the date of manufacture on the tires and not buy tires more than 9 months after manufacturing date.

In your budget range I would simply avoid a timing belt designed car or at least interference type. The cost of replacement is a large chunk of change relative to your perspective purchase price.

They were BELTS…

It appeared that the slack in the worn belt allowed the camshafts’ inherrant oscilations to be transferred to the crank pulley. I had speculated at the time that the key ways were possibly cut too wide and/or the crankshaft was not properly hardened. Other than those two,that type damage has only crossed my path in engines improperly assembled, usually new DIYers.

Houstonrice; please revert to common sense and 1) acknowledge that no amount of academic wishful thinking makes the rubber in your belt any different and less subject to sudden failure at this stage, 2)acknowledge that changing a timing belt properly on a frontwheel drive vehicle is a tricky and difficult task even for a mechanic, and close to impossible for a novice.

I trained as a mechanic and an engineer and changing a timing belt myself is one of the last things I want to do to save money.

You will have to spend UP TO to $500 somehow if you want to own this car for some time to come.

I Agree. I Believe A Timing Chain Usually Lasts Much longer And Gives A Warning To Anybody Concerned About A New Engine Noise Development. Belts Keep A Secret.

Then again, if price is adjusted accordingly, a new belt is an option. I got a dealer to “throw in” and install a new factory H20 pump, tensioner, and belt on a used car to consummate an already great deal on my second to last car purchase.
CSA

My 2 ASE Certificate son and I did a timing belt/water pump/valve adjust on my '04 Civic 1.7l SOC several weeks ago at 103K. Trust me, this is NOT a “$40 tool set from Kragen and get-r-done” repair…!

These jobs can turn out to be the “most espen$ive $400 you ever tried to save” deals.

Thanks Docnick. I bought a Chevy Cobalt 2007 with 24,000 miles, and it was your post that motivated me to search for that brand and model. I owe you and common sense answer…beer/dinner . Email me if you are ever in Houston. Cheers.

Although there is no scientific basis for my opinion, when inspecting a car I pull the T-belt cover and if the brand of the belt is still clearly readable(BANDO or GATES or OEM) and the belt is tight and the timing dead-on I ‘assume(?)’ it is fresh. Even a few thousand miles seems to polish the branding off of T-belts.

Not to sound too sensitive but using the term “Jap” is very offensive to many Asians.

39 Posts and counting…Rubber timing belts. Avoid them. Spend two weeks in Mexico this winter with that money…