Snapped Timing Chain

[Privatewiddle1616]

Hi,

Am a new member to the forum. I would like to know what would cause a new timing chain to snap? I recently had a timing chain fixed about 4 to 5 weeks ago. This Saturday gone the chain snapped. The garage who did the initial repair have said that there might be an underlying cause for this to happen. I thought these chains were meant to be bullet prove! Any ideas please...

Cheers,

Privatewiddle1616

[FROSTYBALLS]

Hello Abdul - welcome to Toyota Owners Club.

Moved to the Yaris club as you may get more responses from there.

[Raistlin]

Hi, Welcome to the club... Enjoy

[LeeroyJones87]

Hi Privatewiddle1616, how old is the car and size engine is it? Did you say you had the chain repaired? If so, I wouldn't advise repairing a chain, it'd need a new one. Chains snapping are very rare unless they have been run with little oil for a while.

[Privatewiddle1616]

Hi Leeroy,

The car is a 2003 M reg Yaris with nearly 100,000 miles on clock and the engine size is cc998. I had already had one timing chain fitted about 2 years ago and I was under the impression that these chains are meant to be bullet proof! About 4-5 weeks ago the engine was making a lot of noise and then it cut out. After researching on the Good Garage Scheme website I found a local garage in my area. They took the car in and confirmed that the issue was with the timing chain and therefore it needed changing. I agreed to have the work done and they replaced it with a new timing chain. About 4 weeks after this repair was done the car cut out whilst driving at 20mpg. I rang the garage again and the owner collected the car and he rang later that day to say that there had been 'some underlying cause' to cause the timing chain to snap and that they were still investigating it further. The car has been in the garage since this Monday morning and I am still waiting to hear from them as to what caused a new chain to snap after barely 4 weeks after they fitted a new one in. Am trying not to think that I have been had! Any thoughts or advice would be really be appreciated. Thanks

[Konrad C]

Chain can life depends on regular oil changes and how the car was driven. Chains are not bullet proof without care.

Did the garage changed the chain without checking the tensioners and making sure the oil ways were clear. Was there enough oil in the engine? Something may have seized.

One thing for sure is the valves will be damaged and maybe the pistons. To be blunt, you will need a rebuild or replacement engine!

Sorry to bring you the bad news Abdul.

Get legal advice on if the garage should pay for the repair.

Konrad

[Madasafish]

As above, I would not repair a chain and the Yaris of 1999- 2005 chain has multi strands and is not repairable.

And any garage which tells you it has repaired a Yaris chain is telling porkies - or has committed a major bodge .

Chain repairs involve removing damaged links and replacing them and joining the chain together with a special link. To remove and refit the links requires a special press to remove the pins and refit new ones and peen over the ends. Usually a chain is joined with a special link which MUST - repeat must - be replaced so the open end is NOT facing in the direction of the chain movement - otherwise it will eventually fly off and the chain break.

I have replaced a Yaris chain - which costs iro £150 - and it comes as a complete chain - no joining required.

Either you have misunderstood what they have told you or they have lied to you.

[Cyker]

I'm pretty sure the OP said a new chain was fitted both times...

The chain should last the life of the engine; The only known causes of failure are down to the oil not being changed for ages or running too low. With regular oil changes the chain should never break!

I'm not sure what else could cause it to break, maybe debris in the sump or it wasn't fitted properly and is grinding/bending somehow. The car hasn't been in an accident in a previous life or something has it...?

[LeeroyJones87]

Hi again,

(longish post)

In my experience there are only a few things that would happen if a chain snapped. (by the way i have never seen this happen on any Toyota up to yet). If the chain snapped around 20 mph, while you were driving, the engine would not just cut out. The car would have abruptly stopped as if you have slammed your brakes on. So i have a feeling this garage maybe telling porkies. Not that there are a lot of common issues with the mk1 yaris, an engine cutting out would most likely be either, air flow meter (although the car would rev steadily on idle), the oil control valve (which supplies oil to the vvt-i controller and would make the car run lumpy) or a blocked fuel filter (which are located inside the top of the fuel tank).

You said about the engine making a funny noise and then it stopped, first time, had you checked to see if it had any oil in?

If not, oil starvation would cause the chain to snap eventually, but it would make a lot of noise for a while beforehand.

Sorry for the long post

[Privatewiddle1616]

Hi,

Really appreciate the replies and input from everyone. The mechanic who did the job said that a new timing chain had had been fixed. At no time was there any mention of any oil problems in the engine by the mechanic while he inspected it on the road side or when he rang from his garage. The car has not been involved any crash/collision with any other vehicle or anything else. When the incident happened the car pretty much continued to move forward a few inches before eventually stopping. I called out Green Flag a few minutes after the incident and the mechanic who arrived checked the dip stick and I saw oil marking the dipstick up to the F mark. He said that he 'suspected a fault with the timing chain and there was no compression on turning over'.

[LeeroyJones87]

Hi again,

Did the enigine stop running when this first happened, as you were moving, or did the engine stop from you turning it off and then wouldn't start again?

If the chain has been "repaired" it shouldn't have been, it should have had a brand new chain, slippers and hydraulic tensioner.

Also if the chain had "snapped" the head of the engine would probably have been damaged due to the piston tops damaging the valves and so would have cost a small fortune to replace.

For the chain to "stretch" or "snap" it must have been running with no oil at all when it snapped. So what the mechanic has said doesn't make sense, the chain wouldn't just break.

Speak to you soon.

[MikeSh]

One thing for sure is the valves will be damaged and maybe the pistons. To be blunt, you will need a rebuild or replacement engine!

Not necessarily. A lot of engines are built with no overlap between the travel of the valves and the sweep of the piston, so that there is no contact if the valve timing is out, or the chain/belt breaks.

It's harder to achieve this with high performance / high compression engines, but standard Yaris don't generally fit that description.

[Konrad C]

Read the following from an old post. http://www.toyotaownersclub.com/forums/topic/79493-timing-chain-snapped-on-idle/

Also there may be a list of engines that are interference/non-interference engines. Mikes point is partially valid, but add economy, efficiency and emissions. These could make the engine an interference type.

A noisy metallic sound from the engine may be a warning that the chain and/or guides are worn. I have heard a few Vauxhalls with this sound.

Vauxhalls have had chain failures on their 2.2 engines due to oil starvation due to blocked oil channels.

I also have read that some cars use plastic chain guides that wear or break.

One final point, overhead cam (OHC) chains are obviously longer than the old overhead valve chains, which did last the life of the engine. That meant more stress.

As I said before, how the engine is treated during its life may determine if the chain fails or not.

In Abduls case, the chain failed in a very short period. If a cambelt failed in the same period, the part supplier and/or fitter is responsible for repairs.

[Madasafish]

Did they replace the chain tensioner with the new chain?

If not, they should have.

That can be the only reason for a new chain to snap - if indeed they fitted one, apart from a lack of oil.

But a faulty tensioner is unlikely to lead to the chain snapping: it is more likely to jump the sprockets and the engine to stop. The chain is then likely to be undamaged.

I suspect the garage are trying to hide something...

But note my choice of words "likely" and "suspect"...

(The tensioner is driven by oil )