Volvo MD2040 Flywheel

[Ammonite]

I've just removed the flywheel housing cover and vibration damper on my MD2040C in order to change the crankshaft rear seal and there's a elongated hole in the flywheel 50mm from the centre just outside of the bolts. It's symmetrical and there's no sign of rust (the brown smears are some form of anti corrosion paste) although it's slightly ragged around the edges. It goes right through the casting. Corrosion, deliberate, casting fault? Any ideas? I've had to order some bolts for my puller so couldn't remove the flywheel today. The hole is about 20mm long x 4mm wide at its widest point and the edges of the hole are solid which makes me think its more likely to be a casting fault than corrosion and has probably been there from new?

 

[penberth3]

I've just removed the flywheel housing cover and vibration damper on my MD2040C in order to change the crankshaft rear seal and there's a elongated hole in the flywheel 50mm from the centre just outside of the bolts. It's symmetrical and there's no sign of rust (the brown smears are some form of anti corrosion paste) although it's ragged around the edges. It goes right through the casting. Corrosion, deliberate, casting fault? Any ideas? I've had to order some bolts for my puller so couldn't remove the flywheel today. It's about 20mm long x 4mm wide
View attachment 188231

A completely wild guess - is there something behind the flywheel, e.g. a loose bolt or other stray part, that's worn a groove and gone right through? I've seen similar things happen, not on a flywheel. If that has happened the flywheel is nearly in two pieces!

You'll obviously be having a good look once you've pulled it off.
.

 

[Ammonite]

A completely wild guess - is there something behind the flywheel, e.g. a loose bolt or other stray part, that's worn a groove and gone right through? I've seen similar things happen, not on a flywheel. If that has happened the flywheel is nearly in two pieces!

You'll obviously be having a good look once you've pulled it off.
.

Now you've got me worried! The bolts should be here by lunchtime tomorrow so I will find out tomorrow afternoon.

 

[penberth3]

Now you've got me worried! The bolts should be here by lunchtime tomorrow so I will find out tomorrow afternoon.

Don't panic, I always think of the worst case!

 

[Ammonite]

Panic over. Having removed the flywheel the hole aligns with the casting on the back so it's been like this since new.