1.9Tdi Head Removal Tips. Belt Tensioner Failure

[Torq]

Hi Guys,

 

The bolt in the center of my 02 Alhambra's timing belt tensioner decided to let go at 75mph on the outside lane of the motorway causing a loss of power and a trip home on the back of a tow truck.  Luckily there was only one other car around, the one I was about to pass, and no one got hurt.

 

I'm assuming that there is valve damage so the head has to come off before I rebuild her so has anyone any tips on how to tackle the inlet and exhaust pipes buried at the back of the engine so I can get the head off.

 

TIA.

 

Torq.

 

 

P.S  The belt kit, including the bolt had only 25k on them before failure.

[insanitybeard]

Does Seat have a different method for clamping the tensioner? Normally (and on my Ford TDI) the tensioner and idler are fitted over studs threaded into the engine block, not bolts, and the tensioner is clamped in position by a nut threaded onto the stud, the timing belt kits I've seen (and the one I fitted) only come with the locknuts, so the studs are not generally items that get changed with the timing belt.

 

As for head removal, the turbo and exhaust manifold are best accessed and disconnected from underneath, whilst removing the scuttle at the rear of the engine bay will open up access to the inlet manifold and EGR valve etc from up top.

 

Also, before you go dismantling the head is it worth trying a leakdown or compression test to check the extent of the damage? Is it at all possible that the timing just got thrown out when the belt tension went and there wasn't any physical contact between pistons and valves?

Edited May 24, 2014 by insanitybeard

[Torq]

My apologies, it was the stud that failed it's actually threaded into the head and not the block. Anyway it sheared about 5mm out of the head so I should be able to get it out, the tensioner also made contact with the cam pulley damaging it and the hydraulic tensioner also broke so 2 more parts to be replaced.  The kit I fitted 25k miles ago came with a new stud so I replaced it.  I've since met someone who bores out the hole to take an M10  stud instead of the standard M8.   

 

Funny thing is that when it happened there was no bang, just a loss of power, I thought the injection system had packed in and was able to drive her to the hard shoulder so it could be just slipped timing.  I guess a leakdown test would be the best bet before getting the spanners out.  Thanks for the advice on head removal if the worst comes to the worst!

[insanitybeard]

If you're very lucky it may not have been quite as catastrophic as it would have been had the timing belt snapped, and the timing may have just drifted off when the tensioner went without the valves smashing into the pistons- you could try replacing the damaged tensioner and sprocket etc before stripping the head, time it up and turn it over manually- take the rocker cover off and inspect the camshaft for damage, if it turns over manually ok with no contact you could try starting it up, might save you some work.

Edited May 24, 2014 by insanitybeard

[Torq]

Just a bit of an update.

 

So I decided to throw a timing belt on and see what would happen.  And the answer was... nothing!  While the crank would turn to some degree the cam would only give around 10deg of rotation.  So I whipped off the cam cover, the injector rockers and the cam.  Every valve is damaged!  None are at fully closed, they all appear to be  partially open so I'm assuming bent.  The cam lobes are damaged as are all the hydraulic followers, one or two show signs of the valve stem trying to break through the top. 

 

So one sheared stud worth about 50c has cost me the top end of the engine and most likely battered the pistons.  It's now looking like a second hand engine is the only option.  

[insanitybeard]

Nightmare, well you've done most of the work to remove the head so you could pull it off and check for damage to the piston crowns and maybe use a DTI gauge to make sure the con rods haven't been bent, you might get away with just a replacement head. Not good though, what a bummer it's done major damage......

[Torq]

Head is off and If I was a bingo player I'd be shouting "House!"  as every valve is bent.  But oddly enough there's not a mark on any of the pistons so I'll be throwing on a 2/h head and hoping for the best.

[Torq]

Well the Alhambra is back on the road about 2 weeks now and all is going well so far. The only silver lining to this was that it forced me to drive my 95 bmw convertible for the best summer we've had in years! It did look a bit odd with 3 child seats but the kids loved it. No room for the wife though! Edited September 21, 2014 by Torq

[SilverBeast]

Well done.  Did you take any pictures? I'm sure they would be a great help to others if you want to post them here. Mirez here would probably be interested too if you have.

[Torq]

Unfortunately the only pic I took was of the trashed head which I will post another day.  But I have a few tips.

 

The bolt at the back right of the cam cover is a nightmare to get off with the egr bits and pieces in the way.  I haven't bothered refitting it after.

 

Don't make work for your self trying to strip the inlet and exhaust manifolds off before taking the head off, do it all in one go

 

Remove the  metal panel and plastic one directly above the engine it will give you the space you need.

 

Don't try to lift the reassembled head with manifolds and turbo back in by yourself.  I did but being realistic it's too heavy. 

 

Mark the diesel pipes, don't mix them up.

 

 

 

Everything went well in the reassembly, the car started once I got the diesel pipes the right way around.  But I have an issue (sigh)  I'm going to open a new thread on it.