1.4 Mpi cylinder head bolts

[KBPhoto]

I am about to change the head gasket in SWMBO's Fabia 1.4 Mpi.

Haynes doesn't say that the cylinder head bolts have to be changed for new ones, but naturally Skoda say they do.

Any advice or guidance from those that have changed head gaskets and whether you changed the bolts or not?

Thanks.

[nath17t]

it is your call thay are not stretch bolts so can be used again just be weary when you take them out as some are different lengths and need to go back in the same holes

[KBPhoto]

I was going to put them in a cardboard temate to ensure each bolt goes back in the same place.

Would the advice be to replace the bolts if their condition warrants it?

In which case, what should I be looking for as a guide as to whether to replace or not?

[waool1988]

If you have the v8 engine then you don't need to change them. However, if you see necking or any kind of plastic deformation on the blots then you should. This engine uses normal bolts and I think they should be good for life, but miss use would ruin them like torquing them too much.

[KBPhoto]

Thanks but it's the 8v 1.4 OHV engine!

Got the bolts all out and they look OK do far. Will clean them up and have a good look.

Some corrosion on some threads and some white residue elsewhere, but physically look to be in good condition.

[anewman]

I understand the usual reason the head gasket fails is that they aren't torqued up properly in the first place. That fact + fact they're not stretch bolts means I'd use them again.

[KBPhoto]

Due mostly to the corrosion we actually used the new bolts!

Seems that the head gasket was leaking and the likely cause was a broken plastic clip inside the thermostat housing.

When I spoke to the dealer to get a new part, he mentioned it straight away as being quite common on the older engines...

[anewman]

Was the clip embeded in the head gasket? The clips always fail on the thermostats, I suspect more than 99% of the 8v MPI engines have had at least one broken thermostat. If anything the clips failing should reduce the probability of head gasket failure, as there would be less back pressure.

Edited 22 August, 2012 by anewman

[KBPhoto]

It was the clip that holds the spring loaded metal bar onto the thermostat itself inside the housing.

Couldn't find the remains of the clip though - It must have disintegrated along the way.

The head gasket was certainly leaking though!

[VWD]

Thanks but it's the 8v 1.4 OHV engine!

Got the bolts all out and they look OK do far. Will clean them up and have a good look.

Some corrosion on some threads and some white residue elsewhere, but physically look to be in good condition.

Haynes doesn't mention new bolts on this engine.

[Tech1e]

I fitted new bolts on mine, just for peace of mind.

[KBPhoto]

VWD: it doesn't you are right. ELSA doesn't say to use new bolts either.

Tech1e: That's how I felt when I tried putting the old bolts back in: they just didn't feel right!

So nice shiny bolts in a nice shiny new cylinder head.

If only I could get the rocker cover as shiny as that! (Just for piece of mind you understand...)

[KBPhoto]

I understand the usual reason the head gasket fails is that they aren't torqued up properly in the first place.

The recomendation is 20Nm on the first pass across all bolts, then another pass adding quarter turn and a third pass with another quarter turn.

We'll see what that takes the torque up to tomorrow morning, but I suspect probably not high enough.

I've been told that 35Nm would be nearer the mark as a final torque figure?

[VWD]

Also a mention in Haynes to keep Head Gasket in wrapper till time to fit it.

[KBPhoto]

Did that - but not entirely sure why (other than to prevent any damage or contamination).

[Calmore]

not seen the gasket in question but the usual reason is to stop dust sticking to the sealant bits.