Timing chain

I have an 05 Ford Focus and am going to have the timing chain changed. Should I do the water pump at the same time on this car? Anything else worth doing?

N.B. I just edited this, because of the first two responses (much appreciated). It was my mistake in calling it a belt, not a chain. I haven’t spoken to a mechanic yet. I like to go in armed with the right info so I can sound like I know what I’m talking about, which obviously I don’t!!


If I were you, I’d ask the shop to explain exactly what belt they intend replacing

Your car does not have a timing belt, it has a timing chain

Don’t take this the wrong way, but the shop probably intends to replace the accessory drive belt, and maybe you misunderstood exactly the words they were using. They may call it the serpentine belt. Same thing, in your case

I wouldn’t bother replacing the water pump, unless it’s leaking, is crusty, or has a bad bearing

Ask them to take a look, while they have the belt off. If it doesn’t look good, that would be the time to replace it. It would cost less to do it, if the belt’s getting replaced, anyways

However . . . if the shop does intend to replace your timing belt, run away and don’t hand them money. If they use the words “timing belt” do not do business with them

Have the shop check the idler and tensioner

Look here.


Your engine uses a timing chain, not a belt.

And if you plan to replace the timing chain, purchase the kit.


But it would be VERY odd to need a timing chain. It should last the life of you car.

How many miles do you have on the car, and why are you replacing the timing chain?

While timing chains are designed to last the life of the engine, and there’s no routine change schedule, occasionally a timing chain and/or its components (usually the tensioner, which in a chain will be a channeled piece with a nylon insert that the chain rides on), will wear out and start making a rattling noise that sounds much like bad lifters. I had to change one at about 200,000 miles on one of my vehicles.

In truth, I suspect that db is right, I suspect that you may have misunderstood. The timing chain only drives the camshafts. There is a rubber belt called a fanbelt, serpentine belt, sometimes a V-belt, and often a drivebelt, that drives the water pump, the alternator, the AC compressor, and the power steering pump (if you have one). Sometimes there’ll even be more than one.

In an engine that drives the camshafts with a rubber belt called a timing belt, the belt also usually drives the water pump, and failure of a water pump can destroy a timing belt, so replacement of the water pump is often recommended when the timing belt is done as a preemptive action. It prevents having to do the expensive job all over again because the water pump failed. But in an engine that uses a chain, like yours, a water pump failure will not affect the valve timing parts, so no other damage will be done; the water pump would just need to be changed, so it’s considered a totally different and unrelated job.

I hope this helps.

By the way, there are technical differences that could be elaborated on regarding V-belts, serpentine belts, and fanbelts, but I thought that level of detail was unnecessary to understand the main question, so I chose not to go into that level of detail. Besides, a lot of guys use the terms interchangeably anyway.

I laugh every time I hear someone say a timing chain should last the life of the vehicle.

That is until the timing chain, guides, and tensioners fail and end the life of the vehicle because of valve damage!

Why do you think they sell timing chain replacement kits?

Because timing chains don’t last forever!


I’m 45 years old, and I remember when by 100,000 miles it was pretty common for a car to need a timing chain. And that was the old V-8 cam in block setup. Now the cams, 2 or 4 of them, are at the top of the cylinder head and people expect that the chains, 1, 2, 3, or 4 of them, will outlast everything else on the car. Where did this idea come from?

Chains have advantages and so do belts. Timing belt replacement is quite predictable and relatively inexpensive. Timing chain failure is not as predictable (in my experience) and much more costly.

I’ve seen a timing a chain so stretched, I was able to remove the timing chain without removing the cam gear or crank gear.

And that was on a GM V8. Circa 1987.


Sure, they can need changing, but the VAST majority don’t. Big difference from timing belts.

I think that a timing chain will last the life of the car if a decent oil change regimen is adhered to.
None of the cars that me or my family members own have ever needed a timing chain even with very high mileage totals.

My 400k+ miles Mercury Sable with 3.0 still had a good chain even at that mileage. How do I know? No noise and now and then I’d tweak the ignition timing a bit. The timing mark on the balancer was always rock steady.

My Lincoln just rolled over 245k miles with zero chain issues on the 4.6 DOHC. Hopefully there will never be a chain issue because the chain kit is pricy and a PITA to swap out.

Sure, they can need changing, but the VAST majority don't. Big difference from timing belts.

The reason is people don’t keep their vehicles long enough. Start thinking about a timing chain at 300k miles. But with a chain - it’ll start to make noise to let you know it needs changing. Sure some vehicles the chain will last much longer. But we’ve seen people in this forum who put over 200k miles on their timing belt before it needed changing.

Over time the tensioners wear, and the metal chain will stretch. Can’t beat the laws of physics.

Given how few vehicles make it past 250k, very few timing chains wear out.

“I remember when by 100,000 miles it was pretty common for a car to need a timing chain.”


However, some only lasted a fraction of that mileage total.
A friend of mine had a '62 Pontiac Tempest with the 4-cylinder engine that was–literally–half of a Pontiac V-8. That engine was incredibly imbalanced to begin with. Then, the timing chain started to do a death rattle inside its case at ~50k miles.

He replaced it, and–guess what?–before he got rid of the car, he had to replace the timing chain again, after another 40-50k miles. That engine was not exactly GM’s finest moment in engineering…

My only timing chain replacement was on a 1984 Impala V8 at 163,000 miles, not because it was broken, but it was getting noisy. I replaced it with a heavy duty double sprocket set and it ran fine until we sold the car at about 300,000 miles.

I also vote for T-Chains NOT Lasting the life of a vehicle. Yes they do last longer in most instances…but are not invincible. Some last A LOT longer than others and I guess you just need to pay attention to the sounds and performance of said vehicle to determine when to change them. On time oil changes also help of course.

I also agree a timing chain replacement at this mileage is a bit premature in this instance.

Ive changed many many a timing chain. Its less often yes but they do wear out. What scares me again is when a Timing Chain only lasts 75-120K on a 02 Dodge Truck with a 5.9 and then other vehicles they seem indestructable. Then I see a 92’ Toyota Truck with a V6 with a timing chain last well over 200K with zero noise or issues… Again the Toyota uses that Infinity Style chain with the square links of steel…Gear Heads here know they type I am describing

There is the “Infinity Type Chain” with those square links and many many layers of steel AND THEN other chains like on the Dodge are similar to a small motorcycle chain…which are common on V8s of some vintage but less common otherwise because they are weaker…thats why they offer “double Roller Chains” as performance upgrades in those cases

.Perhaps its Oil change schedule? Since the chain is also lubed by oil ? It probably helps but, I dunno It could also be the design of the system and load on the chain and tensioners and gears…if its overloaded or something by design they wear out sooner? If said vehicle is capable of easily exceeding the 200K Mile mark I personally know to look and listen for timing chain stretch issues…which creep up on you like Grim Death…Sometimes you don’t notice the slow decline in performance taking place over years of time…


The Ford laminated timing chains with plastic cam sprockets rarely lasted 100,000 miles without jumping on standard transmission vehicles but with automatics the chains often passed 150,000. Roller chains on steel gears were bullet proof. General Motors engines using the laminated chain and plastic cam gear often ran beyond 200,000 miles and often wore a hole in the timing cover without jumping. I found a 4.3l Astro van had jumped time on a rebuilt engine with less than 100 miles years ago. The plastic cam gear was nearly smooth.

I think whether a timing chain lasts the length of the vehicle depends on the design and maintenance. Most do, but if the vehicle is well maintained and well past the 200,000 mile mark, the owner might keep it forever (like I do) and may eventually need a new chain kit. Emphasis on the word “might”.

Everything mechanical wears out eventually. But the variables involved in how soon are myriad. There’s just no predicting. The only thing I can say with certainty is that in my experience it’s rare for a timing chain to wear out before the car becomes an unreliable beater headed for the boneyard anyway. It happens, it happened once to me, but it’s not common.

ASE, I would with great respect disagree that replacing timing belts is relatively inexpensive. IMHO it’s a very expensive procedure for the average worker to have to do on a scheduled basis. $600 or more is not an unusual bill for this process. That’s a lot of money for routine maintenance.

Yeah Rod reminded me of those silly GM V8’s that had steel gears with a laminated plastic cover going over it? I mean WHAT on earth were they thinking? Was this to reduce noise perhaps? Plastic of any flavor has Zero business being used in that manner. No plastic will be able to survive that kind of environment. I fondly recall a Chevy 350 from a 73’ Impala. I bought the entire monstrosity for $100 back in like 88’ …I bought it just for the engine. I wound up installing this engine in my Camaro…it was my first engine swap. I went from the 228ci V6 to the 350 V8 so it was an exciting endeavor for me on many levels. Of course very shortly after the engine was installed I was accellerator happy and I blew up the timing gear… the plastic coating just grenaded under high RPM use. The timing only jumped one tooth and no valve damage occured. I removed and replaced the old gear and chain and cleaned up all that plastic… I wound up with a Double Roller Timing Chain and gears to replace the old one… Never had a problem after that. I think those single row chains of that type (large bicycle chain type) are Nowere near as strong as those laminated type chains… The laminated seem to last much longer and it sort of makes sense because of all those layers of steel… I think it had like 8-12 layers of steel plates to make up the chains width. Those seem to last a long long time

Plastic is still used a lot on the slack side of the chain on the chain tensioner.

In the case of these Toyota Trucks with the V6…the same engine as found in many other Toyotas with V6’s For some reason they last an absurd amount of time/miles. The current record I know about thus far is 300K MILES with no obvious failures… Im sure its stretched by then…but it sure does run nicely…and fuel mileage hasnt changed a bit since it had 80K on the clock.

The design and the type of chain makes a difference. I’m sure also the way the chain is routed and or how much stress is on the chain dictated by the design of the system also contributes to longevity or lack thereof.

I dont know if it was just MONEY that brought on the wave of so many engines being release with T-Belts or what…but there was a time when a T-Belt was unheard of on the roads… It was only the stuff of high performance racing engines and the like back in the early days.

Personally I prefer a Timing Chain for sure…the type found in the Toyota Truck V6. Nobody should need to have a belt replaced at 600+ on each try…with penalty of engine death should you not do it. I bet a lot of people have complained endlessly to their dealers about the Timing Belt…which MAY HAVE brought back the trusty dusty Timing Chain again. You will notice a lot of mfg’s have gone back to chains nowadays… Now what made that happen? Complaints alone? Thats a whole other thread methinks


+1 to Honda’s post in its entirety.

I have no evidence, but I suspect the reason for the nylon sprockets is cost, noise, cost, cost, and cost. The comments on the single row chains are dead-on too. Double row chains would last forever, and double nylon sprockets would probably last forever as well. Heavy duty applications never use single row chains. But there’s the cost…

I too am inclined to suspect that the return to timing chains might have been due to customer dissatisfaction. I would add that people keep their cars two and three times as long now as they did when belts originally became common, and that may be a mitigating factor.

What about the current generation of fully variable valve timing, for both intake and exhaust?

I think a chain is better suited for that

And engines increasingly have such technology, in order to stay competitive and meet fuel economy requirements

I think customer dissatisfaction only played a small role in the move away from the timing belt