Timing Belt Nightmare

@Caddyman Hyundai offered and may still a 10yr/100,000 powertrain warranty since 2000. They also pre 2008 I think had a full fleet of timing belt/interference motors. They have since switch to chains.

I got stuck with a timing belt equipped Honda v6 in an Acura MDX and $700 replacement bill. I fully understand why Honda lingers on with as this motor developed in early 1990’s. To this very day it is still a competitive V6 engine. GM and Chrysler, Ford had nothing to touch a candle to it until recently and in some ways surpassed it with a timing chain.

Although GM completely flubbed up but owned up to it with failing timing chains failing in their 3.6 v6 derivative a few years back.

I don't have a problem at all with belts but I do agree with Caddyman that engines should be designed as non-interference.

That I agree with 100%…My preference is a NON-interference engine with a chain. But IF it is an interference engine…then I prefer a belt…since I keep my vehicles well past 250k miles…a timing belt is a lot easier and less expensive to replace then a chain. When a chain has over 250k miles…they have a tendency to get fatigued…and stretch…At least they start making noise before they slip. But in either case…it’s NOT a deal breaker. It’s way down on the list of what determines my vehicle purchase.

Hyundai’s 100,000 mile warranty is non-transferable and leaves the second owner holding the bag.

Most buyers of new cars trade in regularly and Hyundai gives them a great ride while leaving subsequent owners “in the lurch,” so to speak.

@MikeInNH, the road salt may kill cars early in your neck of the woods, but down here in the South, we have plenty of late 80’s and early 90’s cars still on the road. I have an '88 Supra and '92 Celica, both with timing belts and around 300,000 miles on them, running strong. I see lots of early 90’s cars come into the shop.

I have an '88 Supra and '92 Celica, both with timing belts and around 300,000 miles on them, running strong.

There’s no reason a vehicle with a timing belt can’t run as long as a vehicle with a chain…you just have to replace the belt more often…but the cost of a timing chain replacement is about the cost of 5 timing belt replacements.


How do you figure that GM really owned up to their mistake with the LY7 V6 timing chains?

They did NOT recall those engines. So there are plenty of owners out there who may have to pay for a very expensive timing chain replacement out of their own pockets.

That engine uses 3 timing chains and multiple tensioners. It is supposedly possible to replace the chains with the engine installed. However, it is recommended to remove the engine. I know this because I have full access to the AC Delco training website. They have instructions and training on how to repair that engine.

BTW . . . the LY7 engine has far more problems than “just” the timing chains. Some of them are severe mechanical problems which make the timing chain replacement look cheap.

I know this because I have access to the GM technical website at work.

But you all have to agree:

Replacing 3 timing chains on a modern V6 is way more work than replacing a V6 timing belt

"But you all have to agree:

Replacing 3 timing chains on a modern V6 is way more work than replacing a V6 timing belt "


I just don’t understand all the railing against timing belts here. Belt, chain, gears, something’s gotta turn the camshafts. I don’t care what it is, it’s a mechanical part and some of them are going to wear out and break. Yes, carmakers have increasingly used chains of late, now that the technology exists to do so. But you know what? I do more timing chain repairs now than I did 10 years ago. And the people paying $1800-$2400 for a timing chain job often comment that “Wow, that’s a lot more than the timing belt on my other car.”

“I don’t have a problem at all with belts but I do agree with Caddyman that engines should be designed as non-interference.”

I don’t know if that’s possible with a decent compression ratio. Is it? Some of the old venerable workhorses of yesteryear were interference engines. Cadillac 429 and 472, I think the Ford 302, I even had a Chevy 350 bend valves when the chain let loose at 75mph.

Compression ratio shouldn’t be a problem.


I would maintain that someone could tear apart a flat top piston engine, machine reliefs for the valves, and once running again no one on the planet would ever notice a difference in performance. The improvement would be that the engine has now become a free-wheeler and won’t become damaged goods if the belt snaps. Not saying that anyone would go this far unless they were in the middle of a full engine overhaul and the idea cropped up.

I still think the OP was a victim here; both on the original belt replacement and more than likely a second time by charging a sizeable chunk of money to fix the problem they caused.


“I don’t have a problem at all with belts but I do agree with Caddyman that engines should be designed as non-interference.
Maximum performance race car engines use valve reliefs so I would think a garden variety grocery getter would do just fine with them also.”

Will never happen due to design constraints related to exhaust emissions. I’ve posted on this topic here before. If you look into design mitigations being pursued in modern engines, they are down to the most miniscule contributors. All the low hanging fruit was plucked years ago. Modern designs (within the last decade) have concentrated on an aspect known as “crevice volume” and the quest to minimize it.

Crevice volume is any area of the combustion chamber where gases can collect and escape being fully consumed during the combustion process.

This is why you see the top ring located precariously close to the top of the piston in a modern design. The volume inside of the spark plug tip is a target for eliminating crevice volume as well. No way they would even consider adding valve reliefs to the piston top and dramatically increasing something they are doggedly trying to eliminate…

And the people paying $1800-$2400 for a timing chain job often comment that "Wow, that's a lot more than the timing belt on my other car."

People don’t understand it’s a LOT MORE COMPLICATED. With a chain…you now introduced oil. With oil…now you have gaskets. Don’t have to deal with gaskets in a timing belt. Plus on many vehicles with chains you have to drop the oil pan - that can get very tricky on some vehicles. A good backyard mechanic can do a timing belt…most won’t even attempt a timing chain.

Chains on older engines were not generally too hard to change but some of the modern cars can be an expensive propsition when it comes to chains. The Ford Modulars for example.
One exception to the above older engine scenario might be older SAABs. Chain replacement meant hood off, grill off, radiator out, front suspension partially disassembled, and both motor and transmission out.

As to valve reliefs, I still maintain it’s feasible and done. Just one example below.


The real reason most people hate timing belts, myself included is twofold. Most people drive their car long enough to have to change timing belts, or they don’t even realize they should and thus destroy the engine, at which point they declare the car a lemon.
The vast majority of us don’t ever have to replace a timing chain. My cars always rust out before 200,000 miles and if a timing chain wears out, they make plenty of noise first.

By the time I need to replace a timing chain, I have already replaced the car…Roller chains running in an oil bath are just not the maintenance problem Gilmer belts present to car owners.

Chain against the belt, I’ll take the chain everytime although belts don’t bother me. I’ve never had the need to replace a chain on any of my cars no matter the mileage; even that 400k+ miles Mercury I had.
Regular oil changes and keeping the oil level up usually keeps a chain going forever.

I wonder if there is a way to have the best of both worlds. If changing a timing belt were not much more trouble or expense than changing the alternator belt, then timing belts might be better accepted. Could the belts be routed in such a way or could the manfacturer provide some other accomodation that would make replacing them simple as a accessory drive belt?

To be fair, I’m pretty sure my next vehicle will have a timing chain. It will probably also have an automatic transmission.

The things I like about my current car, that it is light, efficient, and simple, aren’t the kinds of traits I can expect when shopping for a midsize four cylinder pickup truck or economy car. I also can’t expect to continue to find mechanics who know how to properly replace a clutch.

Rod Knox- when did Nascar use timing belts on their pushrod V8s? I am not aware of any but I am always ready to learn something new.

Maybe this will tell the story @oldtimer


As I said…I like a belt with an interference engine…I also no I’m NOT your normal driver. I buy a new car usually every 8-10 years…and for me that means well over 300k miles. I don’t mind doing a timing belt every 100k miles. I’ve had timing chains last over 350k miles…I’ve also seen them start making noise and slipping at 260k miles. And I know the engine was well maintained. If it’s an interference engine and your chain starts to rattle…you seriously better consider getting the chain replaced or buying a new car…or waiting til it slips and buying a new engine. If it’s NOT an interference engine…then wait til it slips. The vehicle can still probably drive…but may loose a good deal of performance.

My preference is to have a chain and a NON-interference engine. But it’s NOT a deal breaker either way.