Broken engine block

[maartenv]

My engine is broken

What probably happened is that the fan broke, was misaligned, and caused so many vibrations to the engine and the waterpump that the mount for the waterpump broke.
Anyone thinks this is fixable?

[sapote]

When did this happen? The block cast iron look so dry and surface rust that it seems it has been seating around long time.

[stash1]

Very difficult, but probably not impossible...you will need a very competent welder. Cast iron can be welded (although not as easily as regular steel), but it's just a matter of trying to get to that area to weld...and then the grinding/finishing will be critical so that everything seals back up as it should.

[Paul46]

I think if you find the right welder then yes you could repair it. Nothing to lose by trying.

[Chanman1029]

How much does welding labor cost? I would just be concerned with the labor running close to the price of a replacement block. This is a very unfortunate situation though, hopefully you can find someone capable to perform that sort of work

[TropicalM3]

Bought an M3 from Copart years ago with the same issue but I just changed the engine. Always wondered what caused it.

[02_lsb]

Years ago, there was a post on the old m3 forum about the fan blades breaking off and causing a whole lotta damage — not to this extent though. I then preemptively replaced my fan blades. As for the misaligned fan, I remember it being nearly impossible to cross thread it, so how would you misalign it?

[maartenv]

When did this happen? The block cast iron look so dry and surface rust that it seems it has been seating around long time.

This happened last week.

How much does welding labor cost? I would just be concerned with the labor running close to the price of a replacement block. This is a very unfortunate situation though, hopefully you can find someone capable to perform that sort of work

I've got 128.000km (80.000 miles) on the block, so it's hard to find a block with these or less kilometers, but replacing it with another block and labour will probably be around 12.000 dollar. Which is still less then the value of the car.

[Slideways]

Are all the water pump threaded holes present? All it looks like it needs is a magnet to hold the piece in place, tack weld the piece, completely weld it and slowly grind the weld smooth until it gets really close to the finish of the rest of the surface. After that, maybe apply a strong gasket maker along with the stock gasket and switch to an electric fan to reduce the stress on the water pump.

[stash1]

How much does welding labor cost? I would just be concerned with the labor running close to the price of a replacement block. This is a very unfortunate situation though, hopefully you can find someone capable to perform that sort of work

A whole helluva lot less than finding a new block (assuming it can be done in-car) and swapping things over -lol

[sapote]

What probably happened is that the fan broke, was misaligned, and caused so many vibrations to the engine and the waterpump that the mount for the waterpump broke.]

Could you post the pic of the broken fan?

There are 2 broken threaded hole on the water pump mounting (labeled T), but the 2 dowel pin holes (labeled D) are fine. I can understand that whatever the force pushing on the water pump that crack the block and the water pump should still attach to the broken half piece, but why the two threaded holes were broken?

I would think a broken fan blade should damage the water pump bearing before it breaks the block. Here is something to consider: the thermostat is bolted to the top of the water pump, and the engine hoist hood is bolted to the thermostat. During engine remove/install, a jerk on the crane pulling chain could crack the this thin section of the block.

As about repair, the two broken threaded holes compound the challenge: the welder needs to build up metal at these holes, then drill and tap the threads precisely or the water pump two dowel pins will not aligned, and so this cannot be done with hand tools. The welder needs to weld back the broken piece to the block, then fill up the crack line with metal, then the flat face needs to be machined back to flat again to seal the coolant. This means the block needs to be removed and sent to the machine shop after welding is done.

[heinzboehmer]

As about repair, the two broken threaded holes compound the challenge: the welder needs to build up metal at these holes, then drill and tap the threads precisely or the water pump two dowel pins will not aligned, and so this cannot be done with hand tools. The welder needs to weld back the broken piece to the block, then fill up the crack line with metal, then the flat face needs to be machined back to flat again to seal the coolant. This means the block needs to be removed and sent to the machine shop after welding is done.

Fixing the threaded holes shouldn't be too hard and I think it could even be done quite precisely with hand tools. Just take the broken piece out of the car, build up more metal on the ears, machine it flat, attach/clamp it to the old water pump and use the bolt holes in the water pump as guides for both drilling and tapping.

Welding the broken part back onto the block and getting it flat is definitely much more of a challenge. I think you can get pretty good results with a grinder and a lot of care (might be better with a small router or something?), but yeah, milling the block would be ideal.


Allow me to suggest the cheapest and most permanent of solutions: https://www.jbweld.com/product/j-b-weld-twin-tube

[cobra]

If you ask what the "right" way to fix it is... replace the part, or have the engine removed to do the work.

But I bet you could make a jig and get it to work by welding it and filing it smooth, and using a thicker gasket with some sealant. Kinda janky but would probably work.

[Slideways]

This guy had the same problem and the mechanic who bought the engine was able to fix the block. Starts at 9:33 -

[maartenv]

I'm not the only one! Here you see it even better from the guy in the video: https://youtu.be/7mYXTK0OBaU?t=88

So they did manage to weld it, good to know!