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Discussion Starter #1
Has anyone on the site had experience of (or even ever heard of ) a valve spring breaking? After a mere 35,000 miles the engine (a 2500cc TDI 88 BHP ) suddenly started shaking violently and making the most appalling clatter which demanded immediate investigation. A local independant VW specialist quickly established that one of the cylinders was not firing hence the vibration but to discover the cause of the clatter required major dismantling.

Eventually on removing the head it was apparent that there had been contact between a valve and a piston. On removing the valve its spring fell out in two pieces. Springs are not a wearing part - they just spend their lives flexing up and down. They may get a little tired after many many thousands of miles but in my book should never actually break. To have done so indicates to me some defect in the manufacture or heat treatment of the spring.

Volkswagen Customer (Don't) Care department thought otherwise. (Well they would wouldn't they) They claimed no history of problems with with the valve springs on this engine and without a shred of supporting evidence claimed that I must have over-revved the engine, which was totally untrue. VW were not interested in inspecting the broken spring ( the nature of a break can tell a lot to a metallagist) nor in interrogating the engine management memory (this might have proved that the engine had not been over revved.) They just maintained that they were not prepared to assist in any way with the substantial repair costs incurred.

Has anyone any experience of anthing similar?
 

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Pedal box guru
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2,616 Posts
Hi,

Yes mine did it a while ago.

You have two choices,

1. Remove head, check everything, may need engine out, crank out, remove con rod/piston replace what is needed.

2. Do not remove head just replace valve spring (this is possible because the piston will hold the valve in an almost closed position when it is at TDC.) pistons on diesel engines are extremely strong and resistant to damage.

I opted for "2", And have driven it for the last year with no problems.

You will have to disturb the cam and pump belts to do either option so it is a good idea to do the belts at the same time.

Cheers Trev.
 

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Pedal box guru
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2,616 Posts
Hi,

I have just re read the post, as you have the head off already, I would take a realistic look at the piston. Are any chunks missing?

How far did you drive it after the spring broke? Mine broke while the engine was overrunning or at low throttle openings,as I was coming down the Cheddar Gorge at the time. I then drove it gently home at little more than tick over for nearly 20 miles, and I didn't bother taking the head off.

I would question the "specialist" part of your VW specialist's description, they should have picked up a broken valve spring as soon as the cam was removed! That's my opinion for what it's worth.

Cheers Trev.
 
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