Cambelt snapped!!!

[danrich123]

My cambelt has snapped on my Fiat Punto, this morning when I tried to start the car.
What sort of damage can this do to the car? is it an expensive thing to get fixed.
The car was frozen over this morning, could this of caused the cambelt to snap?

cheers

 

[RedHerring]

I'm not a mechanic and don't wish to worry you but it could be anything from broken or bent pistons/valves to no visible damage at all. You won't know untill someone looks.
No damage and minimal checking for damage could be about £100 for cambelt raplacement or......
anything up to or even exceeding £1000 for replacement of pistons/valves/head.

Sorry if I've startled you but just based on my experience ( not with Fiat Punto's)

 

[Burnerman]

Unfortunately you can expect valve damage here...the only way to really tell is to put a new belt on, turn the engine slowly by hand before starting up for a compression test. The cold weather has no direct effect on the failure - unless the coolant was frozen of course.
Stiff oil and a belt that is reluctant to bend with the cold are factors, but a good belt can cope with these.
John

 

[Richard C]

Don’t know about Fiat’s specifically but I broke one on a Vauxhall Vectra; bent 12 out of 16 valves but the engine was running. Rebuilding engines is not a problem for me but the parts alone cost over £200 + 1 ½ days work for me to sort it all out. For a garage job, you’re could be looking at anything up to £1000 & the best option may be to get a second-hand head fitted but that in itself can be false economy as you can’t guarantee what it’s really like.

If your engine didn’t run, you may have less damage but you won’t know until it’s stripped down. You could fit a new belt, turn it over gingerly by hand first & if all appears OK then try a compression test as stated but only using the starter motor; don’t whatever you do attempt to start it without checking everything out first. I always change my own cam belts before the recommended service periods & mine still failed prematurely! The cold weather would have put more strain on the belt but it would have failed fairly soon anyway, it just hurried it along a bit.

 

[danrich123]

thanks for the responses,

if the coolant freezing was the cause, would this be worse or better in terms of possible problems, or does that make no difference

 

[Burnerman]

If the coolant was frozen, the belt would have been flung off immediately, but the pistons would still be coming up to kiss the valves so no one knows what the damage is. You could be lucky though - thats why we put a new belt on first just to give it a try.
John

 

[danrich123]

fingers crossed, thanks for all your replys.

 

[^neo^]

if you take the valve cover off and anything looks bent or broken, it should give you an idea as to whether things hit or not! Turn the camshaft sprocket by hand and check to see if the valves are going up and down.
If you was just trying to start it then you will probably be ok

 

[TicklyT]

Much depends on whether the engine is a 'clearance' or 'interference' design.

Some engines are designed with sufficient piston to valve clearance not to mash the pistons into the valves if the cam belt fails, but the design of others means some damage is inevitable, as there's always at least two valves open at any time. If the cam isn't spinning, those valves can't duck as the pitons come up to meet them.

 

[michael10]

Hi as said before you are probably looking at valve damage, however it all depends how much damaged was caused, the vales could have broken off and embedded themselves into the pistons are scored the sides of the cylinder block.

If your antifreeze was to freeze, which is highly unlikely unless it was a very weak mix or plain water then you are looking at even more problems like burst radiator, pipes and even cracks in the cylinder head and block (caused by the water expanding)

For the problem regarding the cam belt snapped i would recommend removing the cylinder head as you would be able to get a accurate view of what has really happened.

Hope it works out ok for you

 

[Nitronick]

My cambelt has snapped on my Fiat Punto,

Which Punto is it? The MK1 with the 1.2(I think) were a safe engine and take about 20 mins to pop a new belt on. Max an hour for an untrained mechanic.

Cam belt would have failed due to water pump being froze up as it is driven off the cam belt. Dont forget to hack some anti-freeze in when you have done the belt.

Let me know if you need some help and I will talk you through it. Just need 10mm and 13mm socket. About 7-8 bolts!